The Federal Agency in Health Protection and Social De-velopment

The Stavropol State Medical Academy

The Department of General Surgery

TRAUMA. TYPES OF TRAUMA. CLINIC.DIAGNOSIS. FIRST AID. TREATMENT OF

TRAUMA.

For Students of General Medicine of the English-speaking Medium

Stavropol 2009

УДК 616-001:617.55(07.07)

ТРАВМА. ВИДЫ ТРАВМ. ЛЕЧЕНИЕ И ПЕРВАЯ ПОМОЩЬ ПРИ ТРАВМАХ (Для студентов лечебного факультета англо-язычного отделения).

Ставрополь: Изд-во СтГМА. – 2008. – 41 с. TRAUMA. TYPES OF TRAUMA. CLINIC. DIAGNOSIS. FIRST AID.

TREATMENT OF TRAUMA. (For Students of General Medicine of the English-speaking Medium). Stavropol: St.SMA. – 2008. – 41 p.

Cоставители:Владимирова О.В., ассистент кафедры общей хирургии Ставропольской

государственной медицинской академии.Линченко В.И., к.м.н., ассистент кафедры общей хирургии

Ставропольской государственной медицинской академии.Кораблина С.С., ассистент кафедры общей хирургии Ставропольской

государственной медицинской академии.

Данное учебное пособие представляет собой комплекс наиболее необходимой информации для студентов 3 курса лечебного факультета при изучении темы травмы, диагностики, лечения и оказания первой помощи при травмах в рамках программы общей хирургии. Предназначено для студентов англоязычного отделения медвузов.

Рецензенты:Лаврешин П.М., д.м.н., профессор, зав.кафедрой общей хирургии

Ставропольской медицинской академии.Знаменская С.В., к.пед.н., доцент, зав.кафедрой иностранных языков с

курсом латинского языка, декан факультета иностранных студентов Ставропольской государственной медицинской академии.

УДК 616-001:617.55(07.07)

Рекомендовано к изданию Цикловой методической комиссией по англоязычному обучению иностранных студентов Ставропольской

государственной медицинской академии

© Ставропольская государственная медицинская академия, 2009

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Trauma is damage or harm caused to the structure or function of the body caused by an outside agent or force, which may be physical, mechanical, chemical or mixed.Common types of injuries : - Burns are injuries caused by excess heat, chemical exposure, or sometimes cold (frostbite). - Fractures are injuries of bones. - Compression trauma.- Wound: cuts and grazes are injuries to the skin, which can cause bleeding (i.e. a laceration). - A bruise is a hemorrhage under the skin caused by contusion. - Damage to a person's sense of self-worth can be considered an emotional injury. An example is harm to one's perception of her or his gender resulting from sexual harassment. - Sports injuries are injuries caused by sport.

Abdominal Trauma, BluntThe care of the trauma patient is demanding and requires speed and efficiency. Evaluat-ing patients who have sustained blunt abdominal trauma remains one of the most chal -lenging and resource-intensive aspects of acute trauma care. Missed intra-abdominal injuries and concealed hemorrhage are frequent causes of increased morbidity and mortality, especially in patients who survive the initial phase after an injury.Physical examination findings are notoriously unreliable for several reasons; a few examples are the presence of distracting injuries, an altered mental state, and drug and alcohol intoxication in the patient.Coordinating a trauma resuscitation demands a thorough understanding of the pathophysiology of trauma and shock, excellent clinical and diagnostic acumen, skill with complex procedures, compassion, and the ability to think rationally in a chaotic milieu.Blunt abdominal trauma usually results from motor vehicle collisions, assaults, recreational accidents, or falls. The most commonly injured organs are the spleen, liver, retroperitoneum, small bowel, kidneys, bladder, colorectum, diaphragm, and pancreas. Men tend to be affected slightly more often than women.PathophysiologyVehicular trauma is by far the leading cause of blunt abdominal trauma in the civilian population. Auto-to-auto and auto-to-pedestrian collisions have been cited as causes in 50-75% of cases. Rare causes of blunt abdominal injuries include iatrogenic trauma during cardiopulmonary resuscitation, manual thrusts to clear an airway, and the Heimlich maneuver. Intra-abdominal injuries secondary to blunt force are attributed to collisions between the injured person and the external environment and to acceleration or deceleration forces acting on the person's internal organs.

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Blunt force injuries to the abdomen can generally be explained by 3 mechanisms.The first is when rapid deceleration causes differential movement among adjacent structures. As a result, shear forces are created and cause hollow, solid, visceral organs and vascular pedicles to tear, especially at relatively fixed points of attachment. For example, the distal aorta is attached to the thoracic spine and decelerates much more quickly than the relatively mobile aortic arch. As a result, shear forces in the aorta may cause it to rupture. Similar situations can occur at the renal pedicles and at the cervicothoracic junction of the spinal cord.The second is when intra-abdominal contents are crushed between the anterior abdominal wall and the vertebral column or posterior thoracic cage. This produces a crushing effect, to which solid viscera (eg, spleen, liver, kidneys) are especially vulnerable.The third is external compression forces that result in a sudden and dramatic rise in intra-abdominal pressure and culminate in rupture of a hollow viscous organ (ie, in accordance with the principles of Boyle law).Clinical History The initial assessment of a trauma patient begins at the scene of the injury, with information provided by the patient, family, bystanders, or paramedics. Important factors relevant to the care of a patient with blunt abdominal trauma, specifically those involving motor vehicles, include the following:The extent of vehicular damage

Whether prolonged extrication was required Whether the passenger space was intruded Whether a passenger died Whether the person was ejected from the vehicle The role of safety devices such as seat belts and airbags The presence of alcohol or drug use The presence of a head or spinal cord injury Whether psychiatric problems were evident

Priorities in resuscitation and diagnosis are established based on hemodynamic stability and the degree of injury. The goal of the primary survey, as directed by the Advanced Trauma Life Support protocol, is to identify and expediently treat life-threatening injuries. The protocol includes the following:

Airway, with cervical spine precautions Breathing Circulation Disability Exposure

Key elements of the pertinent history include the following: Allergies Medications Past medical and surgical history Time of last meal

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Immunization status Events leading to the incident Social history, including history of substance abuse Information from family and friends

Resuscitation is performed concomitantly and continues as the physical examination is completed. The secondary survey is the identification of all injuries via a head-to-toe examination.It is imperative for all personnel involved in the direct care of a trauma patient to exercise universal precautions against body fluid exposure. The incidence of infectious diseases (eg, HIV, hepatitis) is significantly higher in trauma patients than in the general public, with some centers reporting rates as high as 19%. Even in medical centers with relatively low rates of communicable diseases, safely determining who is infected with such pathogens is impossible. The standard barrier precautions include a hat, eye shield, face mask, gown, gloves, and shoe covers. Unannounced trauma arrival is probably the most common situation that leads to a breach in barrier precautions. Personnel must be instructed to adhere to these guidelines at all times, even if it means a 30-second delay in patient care.Physical examination The evaluation of a patient with blunt abdominal trauma must be accomplished with the entire patient in mind, with all injuries prioritized accordingly. This implies that injuries involving the head, the respiratory system, or the cardiovascular system may take precedence over an abdominal injury.The abdomen should neither be ignored nor the sole focus of the treating clinician and surgeon. In an unstable patient, the question of abdominal involvement must be expediently addressed. This is accomplished by identifying free intra-abdominal fluid using diagnostic peritoneal lavage (DPL) or the Focused Assessment with Sonography for Trauma (FAST) examination. The objective is to rapidly identify patients who need a laparotomy.The initial clinical assessment of patients with blunt abdominal trauma is often difficult and notably inaccurate. Associated injuries often cause tenderness and spasms in the abdominal wall and make diagnosis difficult. Lower rib fractures, pelvic fractures, and abdominal wall contusions may mimic the signs of peritonitis. In a collected series of 955 patients, Powell et al reported that clinical evaluation alone has an accuracy rate of only 65% for detecting the presence or absence of intraperitoneal blood. In general, ac-curacy increases if the patient is examined repeatedly and at frequent intervals. However, repeated examinations may not be feasible in patients who need general anesthesia and surgery for other injuries. The greatest compromise of the physical examination occurs in the setting of neurologic dysfunction, which may be caused by head injury or substance abuse.The most reliable signs and symptoms in alert patients are pain, tenderness, gastrointestinal hemorrhage, hypovolemia, and evidence of peritoneal irritation. However, large amounts of blood can accumulate in the peritoneal and pelvic cavities without any significant or early changes in the physical examination findings.

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The abdominal examination must be systematic. The abdomen is inspected for abrasions or ecchymosis. The seat belt sign, ie, a contusion or abrasion across the lower abdomen, is highly correlated with intraperitoneal pathology. Visual inspection for abdominal distention, which may be due to pneumoperitoneum, gastric dilatation, or ileus produced by peritoneal irritation, is important. Ecchymosis involving the flanks (Grey Turner sign) or the umbilicus (Cullen sign) indicates retroperitoneal hemorrhage, but this is usually delayed for several hours to days. Rib fractures involving the lower chest may be associated with splenic or liver injuries. Auscultation of bowel sounds in the thorax may indicate the presence of a diaphragmatic injury. Palpation may reveal local or generalized tenderness, guarding, rigidity, or rebound tenderness, which suggests peritoneal injury.A rectal examination should be performed to search for evidence of bony penetration resulting from a pelvic fracture, and the stool should be evaluated for gross or occult blood. The evaluation of rectal tone is important for determining the patient's neurologic status, and palpation of a high-riding prostate suggests urethral injury.A nasogastric tube should be placed routinely (in the absence of contraindications, eg, basilar skull fracture) to decompress the stomach and to assess for the presence of blood. If the patient has evidence of a maxillofacial injury, an orogastric tube is preferred.As the assessment continues, a Foley catheter is placed and a sample of urine is sent for analysis for microscopic hematuria. If injury to the urethra or bladder is suggested because of an associated pelvic fracture, then a retrograde urethrogram is performed before catheterization.Because of the wide spectrum of injuries, frequent reevaluation is an essential component in the management of patients with blunt abdominal trauma.Pediatric patients are assessed and treated at least initially as adults with respect to the primary and secondary surveys. However, obvious anatomical and clinical differences exist and these must be kept in mind: the child's physiologic response to injury is different; communication is not always possible; physical examination findings become more important; the pediatric patient's blood volume is less, predisposing them to rapid exsanguination; technical procedures tend to be more time consuming and challenging; and a child's relatively large body surface area contributes to rapid heat loss. Perhaps, the most significant difference between pediatric and adult blunt trauma is that, for the most part, pediatric patients can be resuscitated and treated nonoperatively. Some pediatric surgeons often transfuse up to 40 mL/kg of blood products in an effort to stabilize a pediatric patient. Obviously, if this fails and the child continues to be unstable, laparotomy is indicated.Tertiary examinationThis concept was first introduced by Enderson et al to assist in the diagnosis of any in-juries that may have been missed during the primary and secondary surveys. The ter-tiary survey involves a repetition of the primary and secondary surveys and a revision of all laboratory and radiographic studies. In one study, a tertiary trauma survey detected 56% of injuries missed during the initial assessment within 24 hours of admission.

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Aggressive radiographic and surgical investigation is indicated in patients with persistent hyperamylasemia or hyperlipasemia, conditions that suggest significant intra-abdominal injury. Stable patients with inconclusive physical examination findings should undergo radiographic studies of the abdomen.DPL is indicated in blunt trauma as follows:Patients with a spinal cord injury Those with multiple injuries and unexplained shock Obtunded patients with a possible abdominal injury Intoxicated patients in whom abdominal injury is suggested Patients with potential intra-abdominal injury who will undergo prolonged anesthesia for another procedureAn indication for immediate blood transfusion is hemodynamic instability despite the administration of 2 L of fluid to adult patients; this instability indicates ongoing blood loss.Indications for laparotomy in a patient with blunt abdominal injury include the following:Signs of peritonitis Uncontrolled shock or hemorrhage Clinical deterioration during observation Hemoperitoneum findings after FAST or DPL examinationsFinally, surgical intervention is indicated in patients with evidence of peritonitis based on physical examination findings.

The abdomen can be arbitrarily divided into 4 areas. The first is the intrathoracic abdomen, which is the portion of the upper ab-

domen that lies beneath the rib cage. Its contents include the diaphragm, liver, spleen, and stomach. The rib cage makes this area inaccessible for palpation and complete examination.

The second is the pelvic abdomen, which is defined by the bony pelvis. Its contents include the urinary bladder, urethra, rectum, small intestine, and, in females, the ovaries, fallopian tubes, and uterus. Injury to these structures may be extraperitoneal in nature and therefore difficult to diagnose.

The third is the retroperitoneal abdomen, which contains the kidneys, ureters, pancreas, aorta, and vena cava. Injuries to these structures are very difficult to diagnose based on physical examination findings. Evaluation of the structures in this region may require a CT scan, angiography, and an intravenous pyelogram.

The fourth is the true abdomen, which contains the small and large intestines, the uterus (if gravid), and the bladder (when distended). Perforation of these organs is associated with significant physical findings and usually manifests with pain and tenderness from peritonitis. Plain x-ray films are helpful if free air is present. Additionally, DPL is a useful adjunct.While not a contraindication to surgical repair, the evaluation of a patient with blunt abdominal trauma must be prioritized based on the most urgent problems. This implies

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that injuries involving the head, the respiratory system, or the cardiovascular system may take precedence over an abdominal injury. Although a nasogastric tube is routine in order to decompress the stomach and assess for the presence of blood, it is contraindicated in patients with basilar skull fracture. An orogastric tube is preferred if the patient has evidence of a maxillofacial injury.Operative treatment is not indicated in every patient with positive FAST scan results. Hemodynamically stable patients with positive FAST findings may require a CT scan to better define the nature and extent of their injuries. Operating on every patient with positive FAST scan findings may result in an unacceptably high laparotomy rate.

The only absolute contraindication to DPL is the obvious need for laparotomy. Relative contraindications include morbid obesity, a history of multiple abdominal surgeries, and pregnancy.Resuscitative thoracotomy is not recommended in patients with blunt thoracoabdominal trauma who have pulseless electrical activity upon arrival in the emergency department. The survival rate in this situation is virtually 0%. These patients may be allowed a thoracotomy in the emergency department only if they have signs of life upon arrival to the emergency department.Lab StudiesValuable blood studies in the initial evaluation of a patient with blunt abdominal trauma vary by institution but should include a CBC count, coagulation studies, blood type, and blood cross-match (if indicated). The presence of massive hemorrhage is usually obvious from hemodynamic parameters, and the hematocrit value merely confirms the diagnosis. Urine studies include urinalysis, urine toxicologic screen, and serum or urine pregnancy tests in females of appropriate age. Serum electrolyte values, creatinine level, and glucose values are often obtained for reference, but typically they have little or no value in the initial management period. The serum lipase or amylase level is neither sensitive nor specific as a marker for major pancreatic or enteric injury. Normal levels do not exclude a major pancreatic injury. Elevated levels may be caused by injuries to the head and face or by an assortment of nontraumatic causes (eg, alcohol, narcotics, various other drugs). Amylase or lipase levels may be elevated because of pancreatic ischemia caused by the systemic hypotension that accompanies trauma. However, persistent hyperamylasemia or hyperlipasemia should raise the suggestion of significant intra-abdominal injury and is an indication for aggressive radiographic and surgical investigation. All patients should have their tetanus immunization history reviewed. If it is not current, prophylaxis should be given.Imaging StudiesThe most important initial concern in the evaluation of a patient with blunt abdominal trauma is an assessment of hemodynamic stability. In the hemodynamically unstable patient, a rapid evaluation must be made regarding the presence of hemoperitoneum. This can be accomplished using DPL or the FAST scan. Radiographic studies of the

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abdomen are indicated in stable patients when the physical examination findings are inconclusive. Plain radiograph Although the overall value of plain films in the evaluation of patients with blunt abdominal trauma is limited, they can demonstrate numerous findings. The chest radiograph may aid in the diagnosis of abdominal injuries such as ruptured hemidiaphragm (eg, a nasogastric tube seen in the chest) or pneumoperitoneum. The pelvic or chest radiograph can demonstrate fractures of the thoracolumbar spine. The presence of transverse fractures of the vertebral bodies, ie, Chance fractures, suggests a higher likelihood of blunt injuries to the bowel. In addition, free intraperitoneal air, or trapped retroperitoneal air from duodenal perforation, may be seen.Ultrasound The use of diagnostic ultrasonography to evaluate a patient with blunt trauma for abdominal injuries has been advocated since the 1970s. European and Asian investigators have extensive experience with this technology and are leaders in the use of ultrasound for the diagnosis of blunt abdominal trauma. The first American report of physician-performed abdominal ultrasound in the evaluation of blunt abdominal trauma was published in 1992 by Tso and colleagues. Since then, numerous articles have been published in the United States advocating the use of ultrasound in the evaluation of the patient with blunt abdominal trauma. Bedside ultrasonography is a rapid, portable, noninvasive, and accurate examination that can be performed by emergency clinicians and trauma surgeons to detect hemoperitoneum. In fact, in many medical centers, the FAST examination has virtually replaced DPL as the procedure of choice in the evaluation of hemodynamically unstable trauma patients. An examination is interpreted as positive if fluid is found in any of the 4 acoustic windows and is interpreted as negative if no fluid is seen. An examination is deemed indeterminate if any of the windows cannot be adequately assessed. In 1996, the examination was first termed Focused Abdominal Sonography for Trauma. However, in 1997, the FAST Consensus Conference Committee concluded that the acronym should stand for Focused Assessment with Sonography for Trauma. That same year, the American College of Surgeons included the use of ultrasound in the Advanced Trauma Life Support secondary survey. The FAST examination is based on the assumption that all clinically significant abdominal injuries are associated with hemoperitoneum. However, the detection of free intraperitoneal fluid is based on factors such as the body habitus, injury location, presence of clotted blood, position of the patient, and amount of free fluid present. The minimum threshold for detecting hemoperitoneum is unknown and remains a subject of interest. Kawaguchi and colleagues found that 70 mL of blood could be de-tected, while Tiling et al found that 30 mL is the minimum requirement for detection with ultrasound. They also concluded that a small anechoic stripe in the Morison pouch

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represents approximately 250 mL of fluid, while 0.5-cm and 1-cm stripes represent ap-proximately 500 mL and 1 L of free fluid, respectively. The current examination protocol consists of 4 acoustic windows with the patient supine. These windows are pericardiac, perihepatic, perisplenic, and pelvic (known as the 4 Ps). The pericardial view is obtained using a subcostal or transthoracic window. It provides a 4-chamber view of the heart and can detect the presence of hemopericardium, which is demonstrated by the separation of the visceral and parietal pericardial layers. The perihepatic view images portions of the liver, diaphragm, and right kidney. It reveals fluid in the Morison pouch, the subphrenic space, and the right pleural space. The perisplenic view provides views of the spleen and the left kidney and reveals fluid in the splenorenal recess, the left pleural space, and the subphrenic space. The pelvic view uses the bladder as a sonographic window. This view is best accomplished while the patient has a full bladder. In males, free fluid is seen as an anechoic area (sonographically black) in the rectovesicular pouch or cephalad to the bladder. In females, fluid accumulates in the Douglas pouch, posterior to the uterus. Reported sensitivities and negative predictive values for ultrasound in the detection of hemoperitoneum are 78-99% and 93-99%, respectively. FAST examination relies on hemoperitoneum to identify patients with injury. Chiu and colleagues, in their study of 772 patients with blunt trauma undergoing FAST scans, re-ported 52 patients had an abdominal injury. Of the 52 patients, 15 (29%) had no hemoperitoneum on FAST or CT scan results. Hence, the reliance of hemoperitoneum as the sole indicator of abdominal visceral injury limits the utility of FAST as a diagnostic screening tool in stable patients with blunt abdominal trauma. Rozycki et al studied 1540 patients and reported that ultrasound was the most sensitive and specific modality for the evaluation of hypotensive patients with blunt abdominal trauma (sensitivity and specificity, 100%). Hemodynamically stable patients with positive FAST results may require a CT scan to better define the nature and extent of their injuries. Taking every patient with a positive FAST result to the operating room may result in an unacceptably high laparotomy rate. Hemodynamically stable patients with negative FAST results require close observation, serial abdominal examinations, and a follow-up FAST examination. However, strongly consider performing a CT scan, especially if the patient is intoxicated or has other associated injuries. Hemodynamically unstable patients with negative FAST results are a diagnostic challenge. Options include DPL, exploratory laparotomy, and, possibly, a CT scan after aggressive resuscitation.Computed tomography The CT scan remains the criterion standard for the detection of solid organ injuries. In addition, a CT scan of the abdomen can reveal other associated injuries, notably vertebral and pelvic fractures and injuries in the thoracic cavity.

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CT scans, unlike DPL or FAST examinations, have the capability to determine the source of hemorrhage. In addition, many retroperitoneal injuries go unnoticed with DPL and FAST examinations. CT scans provide excellent imaging of the pancreas, duodenum, and genitourinary system. The images can help quantitate the amount of blood in the abdomen and can reveal individual organs with precision. Limitations of CT scans include marginal sensitivity for diagnosing diaphragmatic, pancreatic, and hollow viscus injuries. Also, they are relatively expensive and time consuming and require oral or intravenous contrast, which may cause adverse reactions.Other TestsLaparoscopy The introduction of minimally invasive surgery has revolutionized many surgical diagnostic protocols. In the late 1980s and early 1990s, considerable interest was garnered for the use of laparoscopy in the evaluation and management of blunt and penetrating abdominal trauma. However, subsequent studies revealed major limitations and cautioned against its widespread use. The most important limitation is its inability to reliably identify hollow viscus and retroperitoneal injuries, even in the hands of experienced laparoscopists The procedure involves placing a subumbilical or subcostal trocar for the introduction of the laparoscope and creating other ports for retractors, clamps, and other tools necessary for visualization of the repair. Diagnostic laparoscopy has been most useful in the evaluation of possible diaphragmatic injuries, especially in penetrating thoracoabdominal injuries on the left side. In blunt trauma, diagnostic laparoscopy offers no clear advantage over less invasive modalities such as DPL or CT scan and complications can occur from trocar misplacement.Diagnostic ProceduresDiagnostic peritoneal lavage The idea of evaluating the abdomen by analyzing its contents was first used in the diagnosis of acute abdominal conditions. The principle was described by Salomon in 1906. He described the passage of a urethral catheter by means of a trocar inserted through the abdominal wall to obtain samples of peritoneal fluid to establish the diagnosis of peritonitis from infectious agents (eg, pneumococcal or tuberculous organisms). This technique has since been refined and is now known as abdominal paracentesis. In 1926, Neuhof and Cohen described the sampling of peritoneal fluid in cases of acute pancreatitis and blunt abdominal trauma by passing a spinal needle through the abdominal wall.8 In 1965, Root et al reported the use of diagnostic percutaneous peritoneal lavage in patients after blunt abdominal trauma.9 DPL is indicated in blunt trauma in (1) patients with a spinal cord injury, (2) those with multiple injuries and unexplained shock, (3) obtunded patients with a possible abdominal injury, (4) intoxicated patients in whom abdominal injury is suggested, and

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(5) patients with potential intra-abdominal injury who will undergo prolonged anesthesia for another procedure. The only absolute contraindication to DPL is the obvious need for laparotomy. Relative contraindications include morbid obesity, a history of multiple abdominal surgeries, and pregnancy. Various methods of introducing the catheter into the peritoneal space have been described. These include the open, semiopen, and closed methods. The open method requires an infraumbilical skin incision that is extended to and through the linea alba. The peritoneum is opened, and the catheter is inserted under direct visualization. The semiopen method is identical except the peritoneum is not opened and the catheter is delivered percutaneously through the peritoneum into the peritoneal cavity. The closed technique requires the catheter to be inserted blindly through the skin, subcutaneous tissue, linea alba, and peritoneum. The closed and semiopen techniques at the infraumbilical site are preferred at most centers. The fully open method is the most technically demanding and is restricted to those situations in which the closed or semiopen technique is unsuccessful or is deemed unsafe (eg, patients with pelvic fractures, pregnancy, obesity, or prior abdominal operations). DPL results are considered positive in a blunt trauma patient if 10 mL of grossly bloody aspirate is obtained before infusion of the lavage fluid or if the siphoned lavage fluid (ie, 1 L normal saline infused into the peritoneal cavity via a catheter and allowed to mix, which is then drained by gravity) has more than 100,000 RBC/mL, more than 500 WBC/mL, elevated amylase content, bile, bacteria, vegetable matter, or urine. Only approximately 30 mL of blood is needed in the peritoneum to produce a microscopically positive DPL result. DPL has been shown in some studies to have diagnostic accuracy of 98-100%, sensitivity of 98-100%, and specificity of 90-96%. It has some advantages, including high sensitivity, rapidity, and immediate interpretation. Its limitations include iatrogenic abdominal injury and its high sensitivity, which can lead to nontherapeutic laparotomies. False-positive DPL results can occur if an infraumbilical approach is used in a patient with a pelvic fracture. A pelvic x-ray film should be obtained prior to performing DPL if a pelvic fracture is suggested. Before DPL is attempted, the urinary bladder and stomach should be decompressed. With the availability of fast, noninvasive, and better imaging modalities (eg, FAST examination, CT scan), the role of DPL is now limited to the evaluation of unstable trauma patients in whom FAST results are negative or inconclusive.Medical therapyThe initial goal of paramedics with Advanced Trauma Life Support training is to rapidly assess the patient's airway with cervical spine precautions, breathing, and circulation. This is then followed by splinting of fractures and control of external hemorrhage. The injured patient is at risk for progressive deterioration from continued bleeding and requires rapid transport to a trauma center or the closest and most appropriate facility, with appropriate stabilization procedures performed en route. Hence, securing the airway, placing large-bore intravenous lines, and administering

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intravenous fluid must take place en route, unless delays in transport occur, for instance, if prolonged extrication is required. Upon arrival at the emergency department or trauma center, the first priority is reassessment of the airway. Protection of the cervical spine with in-line immobilization is absolutely mandatory. If intubation is indicated, attempt nasotracheal (ie, if no contraindications) or endotracheal intubation. If unsuccessful, perform cricothyroidotomy. After an airway has been established, adequate ventilatory exchange is assessed by auscultation of both lung fields. Clinical diagnosis of a tension pneumothorax is treated with needle decompression followed by chest thoracostomy tube placement. Other mechanical factors that can interfere with ventilation include sucking chest wounds, a hemothorax, and pulmonary contusion. Treat these aggressively and expediently.The next priority in the primary survey is an assessment of the circulatory status of the patient. Circulatory collapse in a patient with blunt abdominal trauma is usually caused by hypovolemia from hemorrhage. Effective volume resuscitation is accomplished by controlling external hemorrhage and infusing warmed crystalloid solution via 2 large-bore peripheral intravenous lines. Hemodynamic instability despite the administration of 2 L of fluid to adult patients indicates ongoing blood loss and is an indication for immediate blood transfusion. Administer type O, Rh-negative blood if cross-matched or type-specific blood is not available.The primary survey is completed with a brief neurologic assessment of the patient using elements of the Glasgow Coma Scale. The patient is undressed and draped in clean, dry, warm sheets.The secondary survey consists of a complete and thorough physical examination as in-dicated under Physical examination in the Clinical section.Nonoperative management of blunt abdominal traumaNonoperative management strategies based on CT scan diagnosis and the hemodynamic stability of the patient are now being used in the treatment of adult solid organ injury, primarily the liver and spleen. In blunt abdominal trauma, including severe solid organ injuries, selective nonoperative management has become the standard of care.Angiography is a valuable modality in the nonoperative management of adult abdominal solid organ injuries from blunt trauma. It is used aggressively for nonoperative control of hemorrhage, thus avoiding nontherapeutic cost-inefficient laparotomies.Surgical therapyResuscitative thoracotomy in the emergency department is only occasionally life-saving. It is an aggressive, desperate measure to save a patient in whom death is thought to be imminent or otherwise inevitable. Survival with good neurologic recovery is more likely for patients with penetrating trauma than for patients with blunt trauma. Thoracotomy may have a role in selected patients with penetrating injuries to the neck, chest, or extremities and those with signs of life within 5 minutes of arrival to the emergency department.

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A resuscitative thoracotomy is seldom of benefit for patients with cardiac arrest sec-ondary to blunt or head injury or for those without vital signs at the scene of the acci -dent. Patients with blunt thoracoabdominal trauma with pulseless electrical activity upon arrival in the emergency department have a survival rate of virtually 0% and are poor candidates for resuscitative thoracotomy. Patients with blunt trauma may be allowed a thoracotomy in the emergency department only if they have signs of life upon arrival to the emergency department.In a patient with hemoperitoneum from blunt thoracoabdominal trauma, the purpose of a resuscitative thoracotomy in the emergency department is to (1) cross-clamp the aorta, diverting available blood to the coronaries and cerebral vessels during resuscitation; (2) evacuate pericardial tamponade; (3) directly control thoracic hemorrhage; and (4) open the chest for cardiac massage.Indications for laparotomy in a patient with blunt abdominal injury include signs of peritonitis, uncontrolled shock or hemorrhage, clinical deterioration during observation, and hemoperitoneum findings after FAST or DPL examinations When laparotomy is indicated, broad-spectrum antibiotics are given. A midline incision is usually preferred. When the abdomen is opened, hemorrhage control is accomplished by removing blood and clots, packing all 4 quadrants, and clamping vascular structures. Obvious hollow viscus injuries are sutured. After intra-abdominal injuries have been repaired and hemorrhage has been controlled by packing, a thorough exploration of the abdomen is then performed to evaluate the entire contents of the abdomen.After intraperitoneal injuries are controlled, the retroperitoneum and pelvis must be inspected. Do not explore pelvic hematomas. Use external fixation of pelvic fractures to reduce or stop blood loss in this region. Explore large or expanding midline retroperitoneal hematomas, with the anticipation of damage to the large vascular structures, pancreas, or duodenum. Do not explore small or stable perinephric hematomas.After the source of bleeding has been stopped, further stabilizing the patient with fluid resuscitation and appropriate warming is important. After such measures are complete, perform a thorough exploratory laparotomy with the appropriate repair of all injured structures.Postoperative detailsPatients who had gross enteric contamination of the peritoneal cavity are given appropriate antibiotics for 5-7 days. If a pelvic hematoma was found and the patient continues to lose blood after external fixation of a pelvic fracture, arteriography with embolization can be used to stop the small percentage of arterial bleeding found in pelvic fractures.Follow-upThe trend to just observe hemodynamically stable patients with injuries involving the spleen, liver, or kidneys is becoming more popular. In one study of pediatric patients, those with blunt abdominal trauma who were hemodynamically stable after less than 40 mL/kg fluid replacement, had proven evidence of solid organ injuries, and remained

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stable were admitted to the pediatric intensive care unit under surgical management. No deaths and no immediate or long-term complications were reported in this group. If the decision has been made to observe the patient, closely monitor vital signs and frequently repeat the physical examination. An increased temperature or respiratory rate can indicate a viscus perforation or an abscess formation. Pulse and blood pressure can also change with sepsis or intra-abdominal bleeding. The development of peritonitis based on physical examination findings is an indication for surgical intervention.Complications associated with blunt abdominal trauma include but are not limited to the following: Missed injuries Delays in diagnosis Delays in treatment Iatrogenic injuries Intra-abdominal sepsis and abscess Inadequate resuscitation Delayed splenic rupture

Abdominal Trauma, PenetratingPathophysiologyA GSW is caused by a missile propelled by combustion of powder. These wounds involve high-energy transfer and, consequently, can have an unpredictable pattern of injuries. Secondary missiles, such as bullet and bone fragments, can inflict additional damage. Military and hunting firearms have higher missile velocity than handguns, resulting in even higher energy transfer. Close-range shotgun injuries often cause signif-icant tissue damage and should be considered high-energy transfer injuries as well.Stab wounds are caused by penetration of the abdominal wall by a sharp object. This type of wound generally has a more predictable pattern of organ injury. However, occult injuries can be overlooked, resulting in devastating complications.ClinicalAssessment of the patient begins at the scene of the incident by emergency medical service (EMS) personnel. Basic or advanced life support measures are applied at the scene and en route to the emergency department. Upon arrival at the emergency department, communication of the incident history and the patient's vital signs to the emergency or trauma team is of paramount importance. Advanced trauma life support protocols are initiated. Airway protection and ventilatory support are followed by circulatory resuscitation with fluid infusion. Patients who present with hypotension are already in class III shock (30-40% blood volume loss), and they should receive blood products as soon as possible. Physical examination includes inspection of all body surfaces, with notation of all penetrating wounds. Multiple wounds may represent entrance or exit wounds and must not be labeled as such, since multiple missiles or foreign objects may be retained within the body.

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Examination of the abdomen in a patient who is awake may indicate peritoneal signs, such as pain and guarding and rebound tenderness, which necessitate exploration without delay. Abdominal distension in an unresponsive patient may indicate active internal bleeding that also requires exploration, especially in combination with hypotension. Rectal examination is performed on all patients with PAT, as blood per rectum and high-riding prostate can indicate bowel injury and genitourinary tract injury, respectively. Notation of blood at the urethral meatus is also a sign of genitourinary tract injury. When immediate operative intervention is not requisite, further evaluation ensues with laboratory testing and diagnostic and imaging studies.Each area of the torso has anatomical boundaries, as follows:

Thoracoabdominal area – Nipples to the 12th rib, between anterior axillary lines

Abdomen – Nipples to anus, between anterior axillary lines Flank – Between ipsilateral anterior and posterior axillary lines Back – Below the tip of the scapula, between posterior axillary lines Intraperitoneal abdominal organs include the solid organs (ie, spleen, liver) and

the hollow viscus organs (ie, stomach, ileum, jejunum, transverse colon).Retroperitoneal organs include the duodenum, pancreas, kidneys, ureters, urinary bladder, ascending and descending colon, major abdominal vessels, and rectum.

Lab StudiesAll patients should undergo certain basic laboratory testing, as follows: Complete blood count (CBC) provides a baseline value for later comparison, even though it may not reveal the extent of active bleeding. Basic chemistry profile (BMP) also reveals any baseline renal insufficiency or electrolyte abnormalities. Coagulation studies (PT/INR + PTT) may suggest development of coagulopathy. Arterial blood gas (ABG) provides important information regarding acid-base balance and, thus, the hemodynamic stability of the patient. Urine dipstick may reveal occult blood indicative of genitourinary tract injuries. Female patients should have urine pregnancy testing. Patients who arrive in shock should be typed and crossed for 4-8 units packed red blood cells.  Ethanol and drug screens are also standard practice in trauma patients. Studies have shown that even brief intervention and counseling in patients at the time of admission for trauma injury has positive outcomes.Imaging StudiesMany imaging modalities can be useful in the evaluation of a patient with PAT.

Plain radiograph

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Chest radiograph is obtained on all patients because penetration of the chest cavity cannot be ruled out, even with abdominal stab wounds or even-numbered GSWs. Chest radiograph can reveal hemothoraces/pneumothoraces or irregularities of the cardiac silhouette, which can be a sign of cardiac injury or great vessel injury. Air under the diaphragm indicates peritoneal penetration. Abdominal radiographs in 2 views (ie, AP, lateral) are also obtained on all patients with GSWs to help determine missile trajectory and to account for retained missiles in patients with odd-numbered GSWs. UltrasoundThe focused assessment with sonography for trauma (FAST) uses 4 views of the chest and the abdomen (ie, pericardial, right upper quadrant, left upper quadrant, pelvis) to evaluate for pericardial fluid indicative of cardiac injury and for free peritoneal fluid. Free fluid in the abdomen can be a sign of hemorrhage secondary to liver or splenic lac-eration or, less commonly, of spillage secondary to hollow viscus injury. CT scan   CT scan is used in the evaluation of patients with stab wounds to the flank and the back and in the evaluation of selected patients with abdominal stab wounds and GSWs. Triple contrast (ie, oral, intravenous, rectal) is often used to maximize the sensitivity of this study for peritoneal penetration and intra-abdominal organ injury.Specific signs of peritoneal penetration include a wound tract outlined by hemorrhage, air, or bullet or bone fragments that clearly extend into the peritoneal cavity; the pres -ence of intraperitoneal free air, free fluid, or bullet fragments; and obvious intraperi-toneal organ injury. Intravenous pyelogramThis study is more often used intraoperatively to assess contralateral renal function in a patient with kidney damage necessitating nephrectomy.Diagnostic ProceduresIn patients with PAT, a limited number of procedures are necessary for diagnosis and/or treatment.Nasogastric intubation All patients undergoing endotracheal intubation require decompression of the stomach to decrease the risk of aspiration. Blood in the nasogastric tube can indicate upper gas-trointestinal injury.Foley catheterizationCatheter insertion is required to monitor the fluid resuscitation status of the patient with PAT. The presence of blood in the urine is a sign of genitourinary tract injury.Diagnostic peritoneal lavageDiagnostic peritoneal lavage (DPL) can be performed via either a closed method (ie, small skin puncture with blind insertion of catheter over guidewire) or an open method (ie, insertion of catheter under direct vision after exposure of the peritoneum through a small infraumbilical incision).Aspiration of gross blood is positive for peritoneal penetration and organ injury. If aspiration is negative, 1 liter of sodium chloride is administered through the catheter

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and then retrieved by gravity siphonage. The fluid is then evaluated for the presence of red blood cells (>10,000/mm3), white blood cells (>500/mm3), bile, fibers, or particles, any of which indicate peritoneal penetration and organ injury.While very sensitive and specific, DPL requires a fair amount of time to perform, and it has been supplanted in many institution protocols by FAST, CT scan, and/or laparoscopy.Tube thoracostomyPatients with penetrating wounds to the thoracoabdominal area may require chest tube placement. Absent or significantly decreased unilateral breath sounds necessitate immediate tube thoracostomy to relieve hemothorax/pneumothorax. In other patients, hemothorax/pneumothorax will be identified on chest radiograph.A large-bore (38-40F) chest tube should be placed in the midaxillary line at the fifth intercostal space. Time permitting, liberal local anesthesia is preferred in the patient who is awake. The tube is placed to 20-cm wall suction, and, postprocedure, chest radiograph is performed to confirm placement.   Rigid sigmoidoscopyPatients with blood on rectal examination who are otherwise being managed expectantly (mostly stab wounds) should undergo rigid sigmoidoscopy to rule out rectal injury.Medical therapyResuscitation of the patient with PAT begins immediately upon arrival. At least 2 large-bore peripheral intravenous catheters should be secured; central venous access may be necessary. Fluids should be administered rapidly. Normal saline or Ringer’s lactate solution can be used for crystalloid resuscitation. Patients arriving in shock or with obvious significant bleeding should receive blood products as quickly as possible. Arterial access for continuous blood pressure monitoring is standard. Efforts should be made to limit hypothermia, including warm blankets and prewarmed fluids. Antibiotics should be administered to patients undergoing exploration.Preoperative details Surgical intervention begins with preparation of the patient in the operating room. The patient is placed in the supine position with arms extended. The entire chest, abdomen, and pelvis, including the upper thighs, are prepped and draped. This allows for access to the chest, should the injury tract extend above the diaphragm, and to the vasculature of the groins, should reconstruction become necessary. Fluids and blood products should be readily available (and administered via warm lines), and warming devices should be placed on the patient’s upper and/or lower extremities. Entering the abdominal cavity can release tamponade, resulting in a precipitous drop in blood pressure, so the anesthesia team must be informed when the midline incision is made. Intraoperative detailsEssential components to the trauma laparotomy include control of bleeding, identification of injuries, control of contamination, and reconstruction (if possible). Initial control of bleeding is accomplished with 4 quadrant packing using laparotomy pads. The abdominal wall is retracted, the falciform ligament is taken down, and packs

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are placed above the liver and the spleen and in both sides of the pelvis after the bowel is swept cephalad. Once anesthesia has been given time to catch up with fluid resuscitation, the packs are removed one quadrant at a time, starting away from the sites of apparent bleeding. All areas are examined for injuries; each solid organ and the entire bowel are inspected. Contamination is controlled with the use of clamps, staples, or suture closures. Depending on the character of the defect(s), resection may be necessary. If the patient is stable enough to continue the operation, reconstruction may then be performed.

Occasionally, patients with PAT develop such significant metabolic acidosis and coagulopathy that proceeding with the reconstruction phase of the laparotomy is not possible. In these cases, the operation is considered damage-control surgery, and the abdomen is closed rapidly. Often, a temporary closure with an intravenous fluid bag or mesh (occasionally with a vacuum dressing) is used, as the patient has undergone massive fluid resuscitation and the bowel has become quite edematous, precluding primary closure of the abdomen. The patient is then transported to the intensive care unit for continued resuscitation and warming. Reconstruction then takes place upon re-turn to the operating room in 24-48 hours.In patients with PAT, the possible patterns of intra-abdominal injuries are countless. A brief description of specific organ injuries and the intraoperative approach to their management are outlined below.DiaphragmPenetrating injuries to the diaphragm are graded as follows: (I) contusion; (II) laceration, <2 cm; (III) laceration, 2-10 cm; (IV) laceration, >10 cm; and (V) total tissue loss, >25 cm2. Lower grade injuries may be repaired either via laparotomy or with laparoscopic or thoracoscopic techniques.Essential components of repair include an airtight closure with nonabsorbable suture and liberal saline lavage of the hemithorax if there has been a concomitant bowel injury with soilage of the field. The closure may be running or interrupted, and a chest tube is often placed for drainage. Large defects may require placement of a prosthetic patch.  LiverLiver injuries are also classified by grade. Components of the different grades pertinent to penetrating injuries include the following: (I) nonbleeding capsular tears, <1 cm deep; (II) lacerations, 1-3 cm deep and <10 cm long; (III) laceration, >3 cm deep; (IV) parenchymal disruption involving 25-75% of a lobe or 1-3 segments; (V) parenchymal disruption of >75% of a lobe or >3 segments or juxtahepatic venous injury; and (VI) hepatic avulsion. Operative management of liver injuries can involve many techniques, including simple packing or wrapping, local hemostasis, and resectional debridement. Knowledge of hepatic anatomy is crucial, because exposure and vascular control are necessary for the safe repair of injuries. Packing may successfully control minor hemorrhage; however, packs may need to be left in place and the abdomen closed temporarily. After resuscita-tion is complete, the patient may return to the operating room for removal of the packs,

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at which point bleeding is most often resolved.Several hemostatic agents have been used in liver repair, including thrombin, fibrin sealant, collagen/gel preparations, electrocautery, argon beam and radiofrequency coagulation, omental packing, or even intrahepatic balloon tamponade as in the case of through-and-through injuries. Resectional debridement is much less commonly required in the treatment of penetrating liver injuries but may be accomplished with finger frac-ture, cautery, sutures, clips, or stapler device.SpleenPenetrating injuries to the spleen can cause significant bleeding. Irreparable vascular injuries, including total avulsion and extensive lacerations, are indications for splenectomy. Splenectomy may also be necessary for less substantial injuries for the patient in extremis. Time permitting, the spleen is completely mobilized, and care should be taken not to injure the pancreas. If there is a reparable laceration, digital pressure should be applied at the hilum and interrupted pledgeted splenorrhaphy performed.

KidneyInjuries to the kidney are also graded according to severity, as follows: (I) contusion; (II) lacerations, <1 cm; (III) lacerations, >1 cm; (IV) lacerations to the collecting system; and (V) vascular avulsion.As with spleen injuries, the kidney is salvaged with renography, using pledgeted sutures and wrapping, and capsular reapproximation if at all possible. If nephrectomy is deemed necessary because of the severity of injury or instability of the patient, an intraoperative intravenous pylorogram is performed to confirm function of the contralateral kidney.StomachExposure and thorough inspection of the stomach is necessary to evaluate and treat penetrating injuries to the stomach. This is facilitated by opening of the gastrocolic ligament, which allows entrance into the lesser sac. Injuries extending into the lumen may be repaired quickly with a stapling device.DuodenumInjuries to the duodenum are graded as follows: (I) hematoma; (II) partial thickness lac-eration; (III) laceration disrupting <50% circumference of D1, D3, D4, or 50-75% cir-cumference of D2; (IV) laceration disrupting 50-100% circumference of D1, D3, D4, or >75% circumference of D2, or involving the ampulla or distal common bile duct; and (V) massive disruption of the duodenopancreatic complex or devascularization of the duodenum.The Kocher maneuver is used to mobilize the duodenum, along with the pancreatic head and distal common bile duct, so that penetrating injuries can be fully explored. Primary repair of injury is the goal, with protection of the repair using closed-suction drainage.  Diversion procedures are often used for protection. Duodenal diverticulartization diverts biliary and pancreatic secretions using T-tube drainage and gastric decompression with a gastrostomy. Pyloric exclusion involves closure of the pylorus with nonabsorbable

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suture with bypass via gastrojejunostomy; the pylorus opens spontaneously in 4-6 weeks. Grade V injuries require pancreaticoduodenectomy, which is often done as a staged procedure in the unstable trauma patient.PancreasPancreatic injuries are graded according to the presence or absence of ductal injuries. Grades I and II include superficial or major laceration or contusion without ductal injury, respectively. Grade III injuries are distal transections without duct injury or tissue loss. Grade IV lacerations involve proximal transection or parenchymal injury involving the ampulla. Grade V injuries are massive disruptions of the pancreatic head.After hemorrhage is controlled and the pancreas is exposed, the extent of the injury must be identified. Debridement must be selective to preserve as much endocrine and exocrine function as possible. Grade I and II injuries can be managed conservatively, but Grade III injuries are best treated with distal pancreatectomy and splenectomy. Grade IV injuries require near total pancreatectomy with reconstruction of pancreatic drainage into the gastrointestinal tract with either Roux-en-Y pancreaticojejunostomy or pancreaticogastrostomy. If the patient is too unstable, wide drainage of pancreatic tissue without anastomosis may be necessary. Small bowelControl of contamination is of high priority with penetrating injuries to the small bowel. Clamps or staples may be used for temporary control as the entire length of the small bowel is examined.If less than 50% of the bowel circumference is disrupted, the defect can be closed in a transverse fashion with sutures or staples.If there is a single defect larger than 50% circumference, there are multiple defects in a short segment of bowel, or there is a devascularizing injury to the mesentery, resection of the involved segment is appropriate. Side-to-side stapled anastomosis can be accomplished quickly.In the unstable patient, a damage-control procedure may be performed, with control of contamination and resection of devitalized segments without anastomosis. The patient returns to the operating room within 24-48 hours for reexploration, resection of any further devitalized segments, and restoration of continuity with one or more anastomoses. ColonThe management of colonic injuries depends on the extent of the defect, the amount of contamination, and the stability of the patient. Primary repair may be considered if the patient is hemodynamically stable and if the injury is fairly small with minimal fecal contamination.If the patient has multiple injuries; if the patient has required significant blood product resuscitation; if the patient is acidotic, hypothermic, and coagulopathic; and/or if there is a large defect (>50% of the circumference) and considerable fecal spillage, then a diverting colostomy should be performed.Postoperative details

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Patients should be monitored closely in the surgical intensive care unit after trauma laparotomy. Many patients will remain intubated and require ventilatory support. Attention should be paid to warming the patient, to continuing fluid and blood product resuscitation, to replacing electrolytes, and to monitoring drain outputs. Patients with evidence of ongoing bleeding may benefit from angiographic evaluation for possible embolization; some require reexploration for control of hemorrhage. Patients who have undergone damage-control procedures and/or who have temporary abdominal closures must return to the operating room within 24-48 hours for definitive repair.  Critical Care Considerations in TraumaPatient outcomes after major trauma have improved in regions where comprehensive trauma systems have evolved. Crucial components of such a system should include a coordinated approach to both prehospital care and hospital care and to training providers in both areas. Paramedics and medical staff should be provided with a clear and objective framework for assessing patients, establishing and engaging treatment protocols, following triage guidelines, engaging in transportation and communication protocols, and implementing ongoing performance improvement programs.  It is essen-tial to recognize that care of the significantly injured patient is critical care in that criti-cal care is a concept, not a location.TriageThe most seriously injured patients must be identified in the field and safely transported to a designated trauma center where appropriate care is immediately available. This is the principle of triage and is subject to both under-triage and over-triage. Clearly, from a patient-centered view, over-triage is preferable, but, from a system perspective, over-triage may be problematic in an overcrowded and oversubscribed emergency depart-ment.Trauma scoringTrauma scoring systems describe injury severity and correlate with survival probability. Various systems facilitate the prediction of patient outcomes and the evaluation of aspects of care. The scoring systems vary widely, with some relying on physiologic scores (eg, Glasgow Coma Scale [GCS] score, Revised Trauma Score), and others relying on descriptors of anatomic injury (eg, Abbreviated Injury Score, Injury Severity Score). No universally accepted scoring system has been developed, and each system contains unique limitations. This limitation has resulted in the use of a number of such systems in different centers around the world.Principles involved in the initial assessment of a patient with major trauma are those outlined by the American College of Surgeons (ACS) in their Advanced Trauma Life Support (ATLS) guidelines or those of the Australasian College of Surgeons in the Early Management of Severe Trauma guidelines. The principles involved consist of1) preparation and transport; 2) primary survey and resuscitation, including monitoring, urinary and nasogastric tube insertion, and radiography;

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3) secondary survey, including special investigations, such as CT scanning or angiogra-phy; 4) ongoing reevaluation; 5) definitive care.Preparation and communicationTrauma-receiving hospitals should receive advance communication from emergency medical services care providers about the impending arrival of seriously injured pa-tients. The patient's mechanism of injury, vital signs, field interventions, and overall status should be communicated. This allows for the in-house trauma team to be called and for the emergency department staff to make appropriate preparations. The trauma team members vary based on world geography but incorporate many similar elements, including representation from emergency medicine, trauma, critical care, with or without anesthesia, nursing, respiratory therapy, blood bank, radiology, social services, and registration. A team leader is identified, and it is the team leader's responsibility to ensure that the resuscitation proceeds in an organized and efficient manner through the diagnostic and therapeutic protocols. Additional consultants may be engaged in response to specific injuries. In addition to this team, many trauma centers also have a trauma care coordinator (usually a nurse), who follows the patient through his or her hospital course. On the patient's arrival, a concise transfer of the patient from the paramedics should occur. One person should be talking, while everyone else is listening; this is crucial information for the whole team.  In many trauma centers, the team leader is a senior or chief resident in surgery or emergency medicine, with close supervision from appropriate attending staff.  Increasingly, mid-level practitioners (eg, physician associates, nurse practitioners) may serve in this role as well.

Most trauma centers use a system of prehospital triage that characterizes patients into those with physiologic derangements and those who have a suggestive mechanism of injury.  Those patients with obvious derangements should prompt a full team response, while patients with less injury may be cared for by a modified team complement.Primary surveyThe primary survey aims to identify and treat immediately life-threatening injuries rely-ing on the ABCDE system. This system comprises airway control with stabilization of the cervical spine, breathing (work and efficacy), circulation including the control of external hemorrhage, disability or neurologic status, and exposure or undressing of the patient while also protecting the patient from hypothermia.  These elements are ex-plored below.Airway with control of the cervical spineAirway assessment should proceed while maintaining the cervical spine in a neutral po-sition. The latter is achieved by using a rigid cervical immobilization collar. Airway clearance maneuvers are extensively described elsewhere and are not reviewed in this article. 

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When the airway is in jeopardy, or when the GCS score is less than 8, an artificial airway is essential. Airway control is commonly achieved by means of rapid-sequence orotracheal intubation (OETT) performed with in-line stabilization of the cervical spine. Correct placement of the endotracheal tube is confirmed 1) by the aid of an end-tidal carbon dioxide monitoring device, 2) by observation of the tube passing through the vocal cords, 3) by auscultation of the chest.  Several well-defined options for achieving airway control must be established in the event that OETT placement is not able to be achieved. These options include laryngeal mask airway (LMA), intubating LMA, fiberoptic intubation, percutaneous cricothyroidotomy, and surgical cricothyroidotomy (tracheostomy in children). Tracheal inspection is essential to determine if there is peritracheal crepitus or deviation from the midline indicating potential direct airway injury or intrathoracic pulmonary or major vascular injury.Breathing One must next assess the adequacy of gas exchange.  This is most readily accomplished by visual inspection of thoracic cage movement, palpation of the thoracic cage movement, and auscultation of gas entry.  One is assessing for inequalities from one side to the other, crepitus, and local movement asymmetry as in paradoxic thoracic cage movement in flail chest.  One is also evaluating for signs of impending respiratory fail-ure, such as uncoordinated thoracic cage and abdominal wall movement, accessory muscle use, and stridor.Inadequate ventilation may result in hypoxemia, hypercarbia, cyanosis, depressed level of consciousness, bradycardia, tachycardia, hypertension, or hypotension. As a general rule, until stability has been assured, administer high-flow oxygen by mask to all patients to abrogate the potential for hypoxemia. 

Classic signs of a tension pneumothorax, hemothorax, or combined hemopneumothorax include tracheal deviation, jugular vein distension, hypoxia, tachycardia, and hypotension. Intrathoracic tension physiology is a clinical diagnosis and requires immediate decompression. This is initially commonly accomplished with a 14-gauge catheter-over-needle assembly placed in the second intercostal space (ICS) midclavicular line (MCL).  Patients treated in this way should have a tube thoracostomy placed to manage simple pneumothorax and to evacuate thoracic cavity blood when present.  Life-threatening hemorrhage identified when placing a tube thoracostomy may be managed with a resuscitative thoracostomy.Circulation and hemorrhage control Emergent treatment of patients with exsanguinating hemorrhage or shock can be life-saving. This assessment includes identifying and managing rapid external hemorrhage. This can often be achieved with a simple pressure dressing, but surgical intervention may be required.  As more experience is gained with procoagulant dressings (used prin-cipally by the military), external hemorrhage control may gain pharmacologic support embedded in dressings.

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Shock in trauma patients, defined as inadequate organ perfusion and tissue oxygenation, is most commonly caused by hemorrhage leading to hypovolemia, but many other causes are readily identified, including cardiac tamponade, tension pneumothorax or hemothorax, and spinal cord injury. Signs of shock include tachypnea, tachycardia, decreased pulse pressure, hypotension, pallor, delayed capillary refill, oliguria, and a depressed level of consciousness.  In patients with hypovolemia, the neck veins may be flat. A normal mental status generally implies an adequate cerebral perfusion pressure, while diminished mentation may be associated with shock with or without intracranial trauma. 

ATLS readily identifies 4 different classes of shock. Class I and II shock generally does not need red cell mass restoration and is well managed with asanguineous fluids for plasma volume expansion. Hypotension and disordered menta-tion generally indicate at least class III shock and should prompt plasma volume expan-sion and red cell mass repletion if the hypotension fails to resolve after an initial 2000-cc crystalloid bolus, according to ATLS.   A systematic approach for detecting the source of hypovolemic shock should consider 5 sources of ongoing hemorrhage, as follows: 1) external (eg, from the scalp, skin, or nose), 2) pleural cavities, 3) peritoneal cavity, 4) pelvis/retroperitoneum, 5) long-bone fracture.  Fracture alignment and stabilization is essential in limiting blood loss.  Pelvic fractures may be initially stabilized with a pelvic binder or a wrapped sheet secured with a towel clip as a means of reducing pelvic volume to limit hemorrhage.

Disability During the acute resuscitation period, a brief assessment of neurologic status should be performed. This assessment should include the patient's posture (ie, any asymmetry, decerebrate or decorticate posturing), pupil asymmetry, pupillary response to light, and a global assessment of patient responsiveness. A recommended system is the AVPU method, as follows: A = Patient is awake, alert, and appropriate; V = Patient responds to voice; P = Patient responds to pain; U = Pa-tient is unresponsive. A complementary assessment using the GCS should be made at this time, during the secondary survey, and at any time that the patient's mental status appears to change.  A more detailed assessment of the patient's neurologic status is to be made during the secondary survey.

Exposure Patients should be completely disrobed during the initial assessment and the subsequent secondary survey. This helps ensure that significant injuries are not missed. At the same time, efforts to prevent significant hypothermia, using a warm ambient room (28-30°C),

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overhead heating, and warmed IV fluids, should be instituted. The patient's temperature should be measured on arrival at the emergency department, and strenuous efforts should be made to avoid significant hypothermia during resuscitation and therapeutic intervention.

Ancillary monitors Urinary drainage catheters are commonly placed to assess for genitourinary system hemorrhage and to monitor urine flow.  Precautions to avoid urethral injury should be taken for patients with pelvic trauma and for those who have blood at the urethral meatus. Digital rectal examination to identify a high-riding prostate should precede catheter insertion. Abnormal findings from the rectal examination or concern as to the continuity of the urethra should prompt a retrograde urethrocystogram to identify a urethral injury. If identified, a suprapubic catheter should be inserted, and a urologist should be consulted.

Gastric drainage tubes should be orally inserted into all major trauma patients requiring endotracheal intubation.  Even in the absence of brain injury, oral gastric tube insertion is preferred to decrease the likelihood of sinusitis from drainage pathway obstruction.  Children, in particular, are prone to gastric dilatation, which can significantly impair their respiration and lead to hemodynamic compromise. Immediate decompression may be life-saving. Ongoing monitoring of pulse rate, blood pressure, respiratory rate, oxygen saturation, and temperature is a standard of care in the US.

Radiology Initial imaging in the resuscitation room should be limited to a portable anteroposterior (AP) chest radiograph plus an AP pelvic image if the patient was involved in a high-speed motor vehicle collision or a fall from a height. Prior recommendations for lateral cervical radiography have been supplanted by routine pan-cervical imaging with image reformation using CT scanning, especially if the patient will undergo a brain CT scan.  Definitive clearing of the neck is managed in different ways in different institutions, but certain common features are identified.  Patients with a clear sensorium and no distracting injuries may be clinically cleared if there is no neck pain on palpation and active flexion/extension/rotation.  Patients with a normal CT scan but an abnormal mental status should remain in a rigid cervical immobilization device until they may participate in a physical examination or they undergo early (<72 h postinjury) MRI to detect the presence of ligamentous injury.

Chest radiographs should be assessed for the position of tubes and lines, the presence of treatable life-threatening conditions, including space-occupying lesions, mediastinal widening, lung parenchymal injuries, and injuries to the thoracic cage or vertebral column.

A high-energy pelvic fracture identified on physical examination or pelvis film may

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substantially contribute to shock.  Persistent hypotension suggests the need for early operative external stabilization, operative extraperitoneal pelvic packing, or angioembolization.  Technique selection depends on the facility's resources and practitioner skill set.

Secondary surveyThe secondary survey follows in the wake of correction of immediately life-threatening injury and completion of the primary survey.  Thus, the secondary survey may not occur until after an emergency operation has been completed. The secondary survey includes a detailed history, complete physical examination, additional radiologic examinations, and special diagnostic studies. Many institutions include the focused assessment with sonography in trauma (FAST) examination as part of the primary survey rather than part of the secondary survey.

The history should include an assessment of the following items, which can be remembered by using the AMPLE acronym: A = Allergies; M = Medications; P = Past medical, surgical, and social history; L = Last meal; and E = Events leading to injury, scene findings, notable interventions, and recordings en route to the hospital.

Detailed examination

Head and face and neurology Palpate the entire cranium and face evaluating for injury and instability. Sutures, staples, or Rainey clips may be helpful in controlling bleeding from large scalp flaps. Palpate for facial crepitus and a mobile middle third of the face as a clue to potential difficulty in airway control.  Hemotympanum and the presence of bruising around the eyes (ie, raccoon eyes) and mastoid process (ie, Battle sign) suggest basal skull fracture.

Recheck the pupils, and repeat GCS scoring. Evaluate the cranial nerves, peripheral motor and sensory function, coordination, and reflexes. Identify any neurologic asymmetry.  Patients with lateralizing signs and those with an altered level of consciousness (GCS score of <14) should undergo cranial CT scanning. Patients with traumatic brain injury (TBI) are particularly susceptible to secondary brain injury, in particular from hypoperfusion, hypoxia, hypercarbia, hyperglycemia, hyperthermia, and seizure activity. While primary brain injury and primary brain damage (induced apoptosis after primary brain injury) are beyond the clinician's control, secondary injury is a preventable complication with careful attention to detail.

Neck Maintaining cervical spine stabilization when removing a rigid cervical immobilization device is imperative.  Penetrating injuries of the neck may require angiographic, bronchoscopic, or radiologic examination depending on the level of injury (ie, zone I,

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II, or III).  In particular, zone II injuries that violate the platysma may be readily explored, while those injuries in zone I or III benefit from additional investigation because of the difficulty in identifying and controlling injuries in those zones.

Chest Reexamine the chest. Initiate further investigations as indicated by physical examination findings or radiography results.  While aortography was previously identified as the criterion standard investigation to identify aortic transaction, CT angiography has essentially replaced intra-arterial contrast injection. Transesophageal echocardiography using an omniplane probe may be safely used as well but suffers from difficulty with technology access after hours, dependence on user skill set, problematic probe insertion in patients requiring cervical immobilization, and blind spots at the aortic arch.

Abdomen Inspect, percuss, palpate, and auscultate the abdomen, noting tenderness and examining for fullness, rigidity, guarding, or an obvious bruit (rare). Remember that blood is not always a peritoneal irritant, and hemoperitoneum may occur without obvious external signs.

Inspection of the abdomen may be confounded by distracting injuries and impaired consciousness from TBI, intoxicants, or prescription medications. FAST scans are routine in most emergency departments and serve to establish the presence or absence of fluid in 4 distinct domains: pericardium, right upper quadrant, left upper quadrant, and pelvis.  Diagnostic peritoneal lavage is now rarely used.  Extended FAST scanning may also interrogate the thoracic cavity for evidence of pneumothorax. The practitioner should be aware that FAST scanning is not organ-based imaging, and FAST scanning should not be used to establish the presence or absence of solid organ injury. Hemodynamically acceptable patients with a positive FAST scan generally undergo CT scanning to establish the source of presumed hemorrhage.  Patients with a positive FAST scan who are unstable generally proceed to operative intervention in the emergency department (cardiac tamponade) or the operating room (intraperitoneal hemorrhage).  FAST scanning does not evaluate the retroperitoneum, and a normal FAST scan may coexist with substantial retroperitoneal hemorrhage. Also, a positive FAST scan may indicate ascites instead of blood, especially in those with renal or hepatic impairment.

Limbs Inspect, palpate, and move the limbs to determine their anatomic and functional in-tegrity. Pay attention to the adequacy of the peripheral circulation and integrity of the nerve supply. Arterial insufficiency in patients with a displaced fracture or dislocation requires immediate treatment, generally fracture reduction and/or joint relocation.  Pulse inequality should be assessed by means of an ankle-brachial index with diagnostic

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intervention reserved for those with an absolute ABI difference of 0.2 or greater from one side to the other.  Liberal use of diagnostic plain radiography is essential in excluding extremity fracture in patients with mixed mechanisms of injury and in those who cannot participate in an examination because of significant TBI, intoxicants, or other causes.

Log roll The log roll refers to the slow controlled turning of the patient to each side to assess the dependent part of the supine trauma patient. Care must be taken to avoid secondary injury from an as-yet undiagnosed unstable fracture. This examination concentrates on the back of the head, neck, back, and buttocks, and it includes a rectal examination.  The log roll also provides a convenient time to remove the long immobilization board.  The board has not been shown to prevent injury in the presence of an unstable vertebral fracture, but it is highly correlated with pressure ulceration in patients who remain on the board for prolonged periods of time (ie, until diagnostic intervention is complete).

This procedure should be carried out by at least 4 people. The first person stabilizes the head and neck, the second and third persons turn the patient, and the fourth person examines the patient's dorsum and performs the digital rectal examination.  At the completion of the examination, and if the patient is not on an x-ray film bearing stretcher, the chest x-ray plate is readily positioned behind the patient. Spine imaging most commonly proceeds as part of the CT scan using reformatted images. This technique has been demonstrated to have equal, and in some studies superior, efficacy to AP and lateral thoraco-lumber spine imaging for fracture identification.

ReevaluationDuring the secondary survey, the ABCDE system should be used to constantly reevalu-ate the patient, and an ongoing diagnostic and therapeutic plan should be revised, as in-dicated, by the patient's response to intervention and diagnostic test results.

Shock

Hemorrhagic shock is a condition of reduced tissue perfusion, resulting in the inade-quate delivery of oxygen and nutrients that are necessary for cellular function. When-ever cellular oxygen demand outweighs supply, both the cell and the organism are in a state of shock.

On a multicellular level, the definition of shock becomes more difficult because not all tissues and organs will experience the same amount of oxygen imbalance for a given clinical disturbance. Clinicians struggle daily to adequately define and monitor oxygen utilization on the cellular level and to correlate this physiology to useful clinical param-eters and diagnostic tests.

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The 4 classes of shock, as proposed by Alfred Blalock, are as follows:

Hypovolemic Vasogenic (septic) Cardiogenic Neurogenic

Hypovolemic shock, the most common type, results from a loss of circulating blood volume from clinical etiologies, such as penetrating and blunt trauma, gastrointestinal bleeding, and obstetrical bleeding. Humans are able to compensate for a significant hemorrhage through various neural and hormonal mechanisms. Modern advances in trauma care allow patients to survive when these adaptive compensatory mechanisms become overwhelmed.

Pathophysiology

Well-described responses to acute loss of circulating volume exist. Teleologically, these responses act to systematically divert circulating volume away from nonvital organ sys-tems so that blood volume may be conserved for vital organ function. Acute hemor-rhage causes a decreased cardiac output and decreased pulse pressure. These changes are sensed by baroreceptors in the aortic arch and atrium. With a decrease in the circu-lating volume, neural reflexes cause an increased sympathetic outflow to the heart and other organs. The response is an increase in heart rate, vasoconstriction, and redistribu-tion of blood flow away from certain nonvital organs, such as the skin, gastrointestinal tract, and kidneys.

Concurrently, a multisystem hormonal response to acute hemorrhage occurs. Corti-cotropin-releasing hormone is stimulated directly. This eventually leads to glucocorti-coid and beta-endorphin release. Vasopressin from the posterior pituitary is released, causing water retention at the distal tubules. Renin is released by the juxtamedullary complex in response to decreased mean arterial pressure, leading to increased aldos-terone levels and eventually to sodium and water resorption. Hyperglycemia commonly is associated with acute hemorrhage. This is due to a glucagon and growth hormone–in-duced increase in gluconeogenesis and glycogenolysis. Circulating catecholamines rela-tively inhibit insulin release and activity, leading to increased plasma glucose.

In addition to these global changes, many organ-specific responses occur. The brain has remarkable autoregulation that keeps cerebral blood flow constant over a wide range of systemic mean arterial blood pressures. The kidneys can tolerate a 90% decrease in total blood flow for short periods of time. With significant decreases in circulatory volume, intestinal blood flow is dramatically reduced by splanchnic vasoconstriction. Early and

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appropriate resuscitation may avert damage to individual organs as adaptive mecha-nisms act to preserve the organism.

Age

Hemorrhagic shock is tolerated differently, depending on the preexisting physiologic state and, to some extent, the age of the patient. Very young and very old people are more prone to early decompensation after loss of circulating volume.

Pediatric patients have smaller total blood volumes and, therefore, are at risk to lose a proportionately greater percentage of blood on an equivalent-volume ba-sis during exsanguination compared to adults. The kidneys of children younger than 2 years are not mature; they have a blunted ability to concentrate solute. Younger children cannot conserve circulating volume as effectively as older children. Also, the body surface area is increased relative to the weight, allow-ing for rapid heat loss and early hypothermia, possibly leading to coagulopa-thy.

Elderly people may have both altered physiology and preexisting medical con-ditions that may severely impair their ability to compensate for acute blood loss. Atherosclerosis and decreased elastin cause arterial vessels to be less compliant, leading to blunted vascular compensation, decreased cardiac arteri-olar vasodilation, and angina or infarction when myocardial oxygen demand is increased. Older patients are less able to mount a tachycardia in response to de-creased stoke volume because of decreased beta-adrenergic receptors in the heart and a decreased effective volume of pacing myocytes within the sinoa-trial node. Also, these patients frequently are treated with a variety of car-diotropic medications that may blunt the normal physiological response to shock. These include beta-adrenergic blockers, nitroglycerin, calcium channel blockers, and antiarrhythmics.

The kidneys also undergo age-related atrophy, and many older patients have significantly decreased creatinine clearance in the presence of near-normal serum creatinine. Concentrating ability may be impaired by a relative insensi-tivity to antidiuretic hormone. These changes in the heart, vessels, and kidneys can lead to early decompensation after blood loss. All of these factors in con-cert with comorbid conditions make management of elderly patients with hem-orrhage quite challenging.

History

No single historical feature is diagnostic of shock. Some patients may report fatigue, generalized lethargy, or lower back pain (ruptured abdominal aortic

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aneurysm). Others may arrive by ambulance or in the custody of law enforce-ment for the evaluation of bizarre behavior.

Obtaining a clear history of the type, amount, and duration of bleeding is very important. Many decisions in regard to diagnostic tests and treatments are based on knowing the amount of blood loss that has occurred over a specific time period.

If the bleeding occurred at home or in the field, an estimate of how much blood was lost is helpful.

For GI bleeding, knowing if the blood was per rectum or per os is important. Because it is hard to quantitate lower GI bleeding, all episodes of bright red blood per rectum should be considered major bleeding until proven otherwise.

Bleeding because of trauma is not always identified easily. The pleural space, abdominal cavity, mediastinum, and retroperitoneum are all spaces that can hold enough blood to cause death from exsanguination.

External bleeding from trauma can be significant and can be underestimated by emergency medical personnel.

Scalp lacerations are notorious for causing large underestimated blood loss. Multiple open fractures can lead to the loss of several units of blood.

Physical

The physical examination in patients with hemorrhagic shock is a directed process. Of-ten, the examination will be paramount in locating the source of bleeding and will pro-vide a sense of the severity of blood loss. Differences exist between medical patients and trauma patients in these regards. Both types of patients usually will require concur-rent diagnosis and treatment.

The hallmark clinical indicators of shock have generally been the presence of abnormal vital signs, such as hypotension, tachycardia, decreased urine output, and altered mental status. These findings represent secondary effects of circu-latory failure, not the primary etiologic event. Because of compensatory mech-anisms, the effects of age, and use of certain medications, some patients in shock will present with a normal blood pressure and pulse. However, a com-plete physical examination must be performed with the patient undressed.

o The general appearance of a patient in shock can be very dramatic. The skin may have a pale, ashen color, usually with diaphoresis. The patient may appear confused or agitated and may become obtunded.

o The pulse first becomes rapid and then becomes dampened as the pulse pressure diminishes. Systolic blood pressure may be in the nor-mal range during compensated shock.

o The conjunctivae are inspected for paleness, a sign of chronic anemia. The nose and pharynx are inspected for blood.

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o The chest is auscultated and percussed to evaluate for hemothorax. This would lead to loss of breath sounds and dullness to percussion on the side of bleeding.

o The abdominal examination searches for signs of intra-abdominal bleeding, such as distention, pain with palpation, and dullness to per-cussion. The flanks are inspected for ecchymosis, a sign of retroperi-toneal bleeding. Ruptured aortic aneurysms are one of the most com-mon conditions that cause patients to present in unheralded shock. Signs that can be associated with a rupture are a palpable pulsatile mass in the abdomen, scrotal enlargement from retroperitoneal blood tracking, lower extremity mottling, and diminished femoral pulses.

o The rectum is inspected. If blood is noted, take care to identify inter-nal or external hemorrhoids. On rare occasion, these are a source of significant bleeding, most notably in patients with portal hyperten-sion.

o Patients with a history of vaginal bleeding undergo a full pelvic exam-ination. A pregnancy test is warranted to rule out ectopic pregnancy.

Trauma patients are approached systematically, using the principles of the pri-mary and secondary examination. Trauma patients may have multiple injuries that need attention concurrently, and hemorrhage may accompany other types of insults, such as neurogenic shock.

The primary survey is a quick maneuver that attempts to identify life-threaten-ing problems.

o To assess the airway, ask the patient's name. If the answer is articu-lated clearly, the airway is patent.

o The oral pharynx is inspected for blood or foreign materials. o The neck is inspected for hematomas or tracheal deviation. o The lungs are auscultated and percussed for signs of pneumothorax or

hemothorax. o The radial and femoral pulses are palpated for strength and rate. o A quick inspection is made to rule out any external sources of bleed-

ing. o A gross neurological examination is performed by asking the patient

to squeeze each hand and dorsiflex both feet against pressure. Ad-vanced trauma life support (ATLS) suggests that a "miniature" neuro-logic examination categorizes the patient's level of consciousness by whether the patient is alert, responds to voice, responds to pain, or is unresponsive (ie, AVPU).

o The patient then is exposed completely, taking care to maintain ther-moregulation with blankets and external warming devices.

The secondary examination is a head-to-toe, careful examination that attempts to identify all injuries.

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o The scalp is inspected for bleeding. Any active bleeding from the scalp should be controlled before proceeding with the examination.

o The mouth and pharynx are examined for blood. o The abdomen is inspected and palpated. Distention, pain on palpation,

and external ecchymosis are indications of intra-abdominal bleeding. o The pelvis is palpated for stability. Crepitus or instability may be an

indication of a pelvis fracture, which can cause life-threatening hem-orrhage into the retroperitoneum.

o Long bone fractures are noted by localized pain to palpation and boney crepitus at the site of fracture. All long bone fractures should be straightened and splinted to prevent ongoing bleeding at the sites. Femur fractures are especially prone to large blood losses and should be immobilized immediately in a traction splint.

o Further diagnostic tests are warranted to diagnose intrathoracic, intra-abdominal, or retroperitoneal bleeding.

Causes

Hemorrhagic shock is caused by the loss of both circulating blood volume and oxygen-carrying capacity.

Lab Studies

Generally, laboratory values are not helpful in acute hemorrhage because val-ues do not change from normal until redistribution of interstitial fluid into the blood plasma occurs after 8-12 hours. Many of the derangements that eventu-ally occur are a result of replacing a large amount of autologous blood with re-suscitation fluids.

Hemoglobin and hematocrit values remain unchanged from baseline immedi-ately after acute blood loss. During the course of resuscitation, the hematocrit may fall secondary to crystalloid infusion and re-equilibration of extracellular fluid into the intravascular space.

o No absolute threshold hematocrit or hemoglobin level that should prompt transfusion exists. A hemoglobin concentration of less than 7 g/dL in the acute setting in a patient that was otherwise healthy is con-cerning only because the value most likely will drop considerably af-ter re-equilibration.

o In the absence of preexisting disease, transfusions can be withheld un-til significant clinical symptoms are present or the rate of hemorrhage is enough to indicate ongoing need for transfusion.

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o Patients with significant heart disease are at higher risk of myocardial ischemia with anemia, and transfusion should be considered when values drop below 7 mg/dL.

Arterial blood gas may the most important laboratory value in the patient in se-vere shock.

o Acidosis is the best indicator in early shock of ongoing oxygen imbal-ance at the tissue level. A blood gas with a pH of 7.30-7.35 is abnor-mal but tolerable in the acute setting. The mild acidosis helps unload oxygen at the peripheral tissues and does not interfere with hemody-namics.

o A pH below 7.25 may begin to interfere with catecholamine action and cause hypotension unresponsive to inotropics. Although this is a time-honored concept, recent data do not find evidence of this phe-nomenon.

o Metabolic acidosis is a sign of underlying lack of adequate oxygen delivery or consumption and should be treated with more aggressive resuscitation, not exogenous bicarbonate. Life-threatening acidemia (pH <7.2) initially may be buffered by the administration of sodium bicarbonate to improve the pH. However, be aware that no survival benefit to this practice has been documented.

Coagulation studies generally produce normal results in the majority of pa-tients with severe hemorrhage early in the course. The notable exceptions are patients who are on warfarin, low molecular weight heparin, or antiplatelet medications or those patients with severe preexisting hepatic insufficiency.

If patients are unable to provide adequate medication histories, tests for pri-mary and secondary hemostasis should be ordered. The prothrombin time (PT) and the activated partial thromboplastin time (aPTT) will identify major prob-lems with secondary hemostasis.

o The best test for platelet function is the bleeding time. This test is dif -ficult to perform in the patient with acute hemorrhage.

o An alternative is thromboelastography, which is at least equivalent, and possibly superior, to the bleeding time. This test is an ex vivo analysis of all of the components of clotting and has been used exten-sively in orthotopic hepatic transplantation, cardiac surgery, and trauma.

o Qualitative platelet dysfunction can be inferred in those patients with a clinical coagulopathy and normal PT and aPTT values. Obviously, abnormal PT or aPTT values should be corrected emergently in the context of severe hemorrhage.

Electrolyte studies usually are not helpful in the acute setting. After massive resuscitation, certain abnormalities can occur.

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o Sodium and chloride may increase significantly with administration of large amounts of isotonic sodium chloride. Hyperchloremia may cause a non–ion gap acidosis and significantly worsen an existing aci-dosis.

o Calcium levels may fall with large-volume, rapid blood transfusions. This is secondary to chelation of the calcium by the ethylenedi-aminetetraacetic acid (EDTA) preservative in stored blood. Newer methods of blood banking avoid using EDTA, and the problem of hypocalcemia should be minimized.

o Likewise, potassium levels may rise with large-volume blood transfu-sions.

o Creatinine and blood urea nitrogen usually are within normal limits unless preexisting renal disease is present. Caution should be used when administering iodinated contrast in patients with elevated creati-nine because the dye load could initiate a contrast-induced nephropa-thy in addition to chronic renal impairment.

A blood specimen for type and crossmatch should be obtained as soon as the patient arrives.

For patients who are actively bleeding, 4 U of packed red blood cells (PRBCs) should be prepared, along with 4 U of fresh frozen plasma (FFP). Platelets may be obtained as well, depending on the physician's estimation of the likelihood of the need for platelet transfusion (less commonly needed compared to FFP).

Imaging Studies

Imaging studies are aimed at identifying the source of bleeding. In many types of severe hemorrhage, therapeutic interventions, such as exploratory laparo-tomy, will preclude comprehensive diagnostic studies.

Chest radiographs o Chest radiographs indicate a diagnosis of hemothorax by showing a

large opacity in one or both lung fields. o Hemothoraces large enough to cause shock usually are obvious as a

complete whiteout of one pleural space. Abdominal radiographs

o Abdominal radiographs are rarely helpful. Hemoperitoneum usually will not be visible on plain film.

o Occasionally, a radiograph will have a diffuse ground glass appear-ance, suggesting a large amount of intraperitoneal fluid, but this sign is not reliable.

o Rarely, a ruptured abdominal aortic aneurysm can be diagnosed by noting an incomplete shell (calcified wall) of a dilated aorta.

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o Loss of the psoas shadow unilaterally also can suggest retroperitoneal blood.

Computed tomography scan o Computed tomography (CT) scan is sensitive and specific for diag-

nosing intrathoracic, intra-abdominal, and retroperitoneal bleeding. It is the test of choice for diagnosing bleeding in these cavities.

o CT scan only has an adjunctive role in the diagnosis of GI bleeding when other tests have suggested a mass lesion as part of the disease process.

o Ultrasound is rapidly replacing CT scan as the diagnostic test of choice for the identification of hemorrhage in major body cavities. It is, of course, limited in its ability to evaluate the retroperitoneum. Retroperitoneal evaluation remains the purview of the CT scan.

Esophagogastroduodenoscopy o Esophagogastroduodenoscopy (EGD) is the test of choice for acute

upper GI bleeding because it can provide a specific diagnosis and has therapeutic potential.

o Lavage the stomach with a large gastric tube before the procedure to remove as much clot as possible.

o Capabilities for epinephrine injection and bipolar circumactive probe (BICAP) cautery should be available.

o Aortoenteric fistulas are very rare and usually are caused by erosion of an aortic aneurysm into the duodenum. EGD may be able to diag-nose this problem, but the false-negative rate in these cases is very high.

Colonoscopy o Colonoscopy is used to diagnose acute lower GI bleeding. o It is considered by most to be difficult to perform in the acute setting

and may fail to show the exact source of bleeding in cases of rapid hemorrhage.

o Although some experience exists with therapeutic interventions, such as cauterization for acute arteriovenous malformation bleeding, these techniques are not used widely.

Ultrasound o Ultrasound is a useful technique to diagnose intraperitoneal bleeding

in the trauma patient. o The focused abdominal sonographic technique (FAST) examination

realistically has replaced diagnostic peritoneal lavage as the test of choice for identifying intraperitoneal fluid in the trauma patient.

o The FAST examination includes 4 anatomical views of the peri-cardium, abdomen, and pelvis that attempt to identify free intra-ab-dominal fluid.

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Bedside ultrasound can be performed by radiologists, surgeons, and emergency medicine physicians who have specialized training and certification.

Angiography is extremely useful in the diagnosis of acute hemorrhage from many different sources. Its utility is limited by the availability of an angiogra-pher on a timely basis.

o In cases of lower GI bleeding, angiography is one of the best tests to localize a bleeding source. Angiography usually can detect bleeding that is at least 1-2 mL/min. Selective angiograms of the celiac, supe-rior mesenteric, and inferior mesenteric arteries are performed to lo-cate the areas of bleeding. The best time to perform the examination is when the patient is actively bleeding. Once the source is identified, embolotherapy may be used as an acute means of arresting hemor-rhage. This will allow resuscitation to proceed prior to operation. If embolotherapy is not used, then identifying the site of bleeding will allow a more limited bowel resection to be performed if surgery be-comes indicated during the admission.

o Angiography can be used for diagnosis and management of severe bleeding from pelvic fractures. Although most bleeding from severe pelvic fractures is venous in origin, occasional significant arterial bleeding can be diagnosed and treated effectively with embolization.

o Severe liver injuries pose a challenge to the trauma surgeon because of the large amounts of blood loss and the difficulty in gaining surgi -cal control quickly. Many severe liver injuries now are being diag-nosed and treated with angiographic embolization. Angiography is in-creasingly considered first-line intervention (before laparotomy) for severe liver injuries in centers that are equipped to perform rapid an-giography and angiographic intervention. Similar methods may be used for other solid organ injuries, such as the spleen and kidney.

o Angiography may be used in the diagnosis of massive hemoptysis of unclear etiology. Selective angiography of the bronchial arteries, combined with a selective pulmonary angiogram through a separate venous catheterization can localize bleeding.

o The role of angiography in upper GI bleeding is more limited. Hemo-bilia is a rare cause of upper GI bleeding. If blood definitely is ob-served emanating from the ampulla of Vater, angiography should be performed to localize and control the source of bleeding.

Nuclear medicine scanning can be used to localize GI bleeding. o A tagged red blood cell scan may help differentiate upper from lower

GI bleeding and may provide anatomic information, such as identify-ing bleeding from the right versus left colon. Overlap of structures will confound the utility and accuracy of this test.

o The test requires a significant amount of time to complete, but it is very sensitive, detecting bleeding as slow as 0.5 mL/min.

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Procedures

Diagnostic peritoneal lavage is a bedside procedure that utilizes a small mid-line laparotomy and insertion of a catheter directly into the peritoneal cavity. Percutaneous insertion techniques are available but carry an increased risk of injury to underlying structures.

o The intent of diagnostic peritoneal lavage is to determine if significant intra-abdominal bleeding or injuries to hollow organs are present.

o If more than 5 mL of blood is aspirated, the test result is said to be grossly positive and laparotomy usually is indicated.

o If blood is not aspirated, 1000 mL of warm lactated Ringer’s solution is infused into the abdomen and then allowed to drain out into the IV bag. The contents of the bag are examined in the lab. A red blood cell count of greater than 10,000 per µL is considered a microscopically positive test result.

o Other conditions that make the test results positive include the follow-ing: white blood cell count greater than 500/µL; high levels of amy-lase, lipase, or bilirubin; and particulate matter that may be from an intraluminal source.

Central venous access o Central venous access is considered an adjunct to large-bore (16- or

14-gauge) peripheral IV lines. o Flow through a catheter is inversely proportional to the length and di-

rectly proportional to the diameter. Thus, long small-caliber lines, such as a standard triple lumen catheter, will deliver significantly less volume than a short large-caliber line, such as a peripheral IV.

Large-bore (12F) central resuscitation lines o This large-bore sheath introducer is used for volume resuscitation.

Smaller sizes are less effective but are more effective than a standard multi-lumen central venous catheter.

o If significant intra-abdominal bleeding from a venous injury is sus-pected, volume lines should be avoided in the femoral veins.

o In general, access above and below the site of an injury is a good practice. This allows the operator to switch the primary resuscitation lines should one or more be ineffective or be positioned directly be-low an injury in the vessel in which the catheter resides.

Medical Care

The primary treatment of hemorrhagic shock is to control the source of bleeding as soon as possible and to replace fluid.

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In controlled hemorrhagic shock (CHS), where the source of bleeding has been oc-cluded, fluid replacement is aimed toward normalization of hemodynamic parameters. In uncontrolled hemorrhagic shock (UCHS), in which the bleeding has temporarily stopped because of hypotension, vasoconstriction, and clot formation, fluid treatment is aimed at restoration of radial pulse or restoration of sensorium or obtaining a blood pressure of 80 mm Hg by aliquots of 250 mL of lactated Ringer's solution (hypotensive resuscitation).

When evacuation time is shorter than 1 hour (usually urban trauma), immediate evacua-tion to a surgical facility is indicated after airway and breathing (A, B) have been se-cured ("scoop and run"). Precious time is not wasted by introducing an intravenous line. When expected evacuation time exceeds 1 hour, an intravenous line is introduced and fluid treatment is started before evacuation. The resuscitation should occur before, or concurrently with, any diagnostic studies.

Crystalloid is the first fluid of choice for resuscitation. Immediately administer 2 L of isotonic sodium chloride solution or lactated Ringer’s solution in response to shock from blood loss. Fluid administration should continue until the patient's hemodynamics become stabilized. Because crystalloids quickly leak from the vascular space, each liter of fluid expands the blood volume by 20-30%; therefore, 3 L of fluid need to be admin-istered to raise the intravascular volume by 1 L.

Alternatively, colloids restore volume in a 1:1 ratio. Currently available colloids include human albumin, hydroxy-ethyl starch products (mixed in either 0.9% isotonic sodium chloride solution or lactated Ringer’s solution), or hypertonic saline-dextran combina-tions. The sole product that is avoided routinely in large-volume (>1500 mL/d) restora-tion is the hydroxy-ethyl starch product mixed in 0.9% isotonic sodium chloride solu-tion because it has been associated with the induction of coagulopathy. The other prod-ucts have not been so implicated.

PRBCs should be transfused if the patient remains unstable after 2000 mL of crystalloid resuscitation. For acute situations, O-negative noncrossmatched blood should be admin-istered. Administer 2 U rapidly, and note the response. For patients with active bleed-ing, several units of blood may be necessary.

If at all possible, blood and crystalloid infusions should be delivered through a fluid warmer.

A blood sample for type and cross should be drawn, preferably before blood transfusions are begun. Start type-specific blood when available.

Patients who require large amounts of transfusion inevitably will become coag-ulopathic. FFP generally is infused when the patient shows signs of coagulopa-thy, usually after 6-8 U of PRBCs.

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Platelets become depleted with large blood transfusions. Platelet transfusion also is recommended when a coagulopathy develops.

Surgical Care

The decision regarding whether to operate to control bleeding is complicated and be-yond the scope of this article. Some generalities, however, may be advanced.

Acute life-threatening bleeding within the abdominal or thoracic cavity is an indication for operation.

Retroperitoneal bleeding is difficult to control operatively and generally is treated nonoperatively.

Severe upper GI bleeds should be managed first by EGD, with the possibility of cauterizing or injecting the bleeding source with epinephrine. Failure of en-doscopic management usually is an indication for surgery.

Confirm the location of a lower GI bleed before operative intervention is per-formed.

Severe vaginal bleeding should prompt early involvement of the gynecolo-gist.  

o Ectopic pregnancies are treated with immediate surgery. o Abruptio placenta is a true emergency and should prompt immediate

cesarean section.

Complications

The primary complication is death. The entire spectrum of organ failures may be the sequelae of resuscitated hem-

orrhagic shock. The cascade of systemic inflammatory response syndrome (SIRS) progressing

to multiple organ failure syndrome (as described by the late Roger Bone, MD) complicates the cases of approximately 30-70% of patients who present with hemorrhagic shock and survive their initial resuscitation.

Prognosis

Prognosis is related to the ability to be resuscitated from shock, as well as the underlying illness or injury, not the presentation of hemorrhagic shock.

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