Hypovolemic Hypovolemic ShockShock

General Surgery OrientationGeneral Surgery OrientationMedical Student Lecture SeriesMedical Student Lecture Series

Juan Duchesne MD, FACS, FCCP, FCCMJuan Duchesne MD, FACS, FCCP, FCCMAssociate Professor of Trauma/Critical Care Surgery/AnesthesiaAssociate Professor of Trauma/Critical Care Surgery/Anesthesia

Hypovolemic ShockHypovolemic ShockVascular compartments:Vascular compartments:

TBW (60% of IBW)TBW (60% of IBW) Total Body WaterTotal Body Water

ICW (40%)ICW (40%) ECW (20%)ECW (20%) Intracellular WaterIntracellular Water Extracellular Extracellular

WaterWater

InterstitiumInterstitium PlasmaPlasma(1/3)(1/3) (2/3)(2/3)

Hypovolemic ShockHypovolemic ShockLoss of circulating blood volume (Plasma)Loss of circulating blood volume (Plasma)

Normal Blood Volume:Normal Blood Volume:- 7% IBW in adults- 7% IBW in adults

- 9% IBW in kids- 9% IBW in kids

ShockShockHypovolemicHypovolemic

SepticSeptic

Cardiogenic (Obstructive)Cardiogenic (Obstructive)

NeurogenicNeurogenic

AdrenalAdrenal

ShockShockMost common forms in surgery:Most common forms in surgery:

HypovolemicHypovolemic

SepticSeptic

CardiogenicCardiogenic

Hypovolemic ShockHypovolemic ShockDefinition:Definition:Reduction in intravascular volume leading Reduction in intravascular volume leading

to insufficient oxygen delivery to cells to insufficient oxygen delivery to cells (mitochondria)(mitochondria)

Hypovolemic ShockHypovolemic ShockReduced intravascular volume?Reduced intravascular volume?

No oxygen delivery! No oxygen delivery!

No aerobic metabolism! No aerobic metabolism!

Then…Then… Metabolic acidosis (lactic acid production)Metabolic acidosis (lactic acid production) Endoplasmic recticulum swellingEndoplasmic recticulum swelling Mitochondrial damageMitochondrial damage Cell Death!Cell Death!

EFFECTIVE RESUSCITATIONEFFECTIVE RESUSCITATION

IRREVERSIBLE

IRREVERSIBLE

Hypovolemic ShockHypovolemic Shock

Tension Tension Pneumothorax Pneumothorax ~ impairment ~ impairment of ventricular of ventricular filling.filling.

Hypovolemic ShockHypovolemic ShockHemorrhagic shock (3 categories)Hemorrhagic shock (3 categories)

1. Compensated:1. Compensated:– 0-20% of blood loss0-20% of blood loss

– Blood pressure is maintained via increased Blood pressure is maintained via increased vascular tone and increased blood flow to vital vascular tone and increased blood flow to vital organsorgans

HypovolemicHypovolemic ShockShockThe body’s response:The body’s response:

Compensated shock Baroreceptor mediated Compensated shock Baroreceptor mediated vasoconstriction!vasoconstriction!

Increased epinephrine, vasopressin, angiotensinIncreased epinephrine, vasopressin, angiotensinResults in:Results in:

– TachycardiaTachycardia– TachypneaTachypnea– Lowered pulse pressureLowered pulse pressure– Slightly lowered urine outputSlightly lowered urine output

Hypovolemic ShockHypovolemic ShockThe Organs who win:The Organs who win:BrainBrainHeartHeartKidneysKidneysLiverLiver

The Organs who lose:The Organs who lose:SkinSkinGI tractGI tractSkeletal MuscleSkeletal Muscle

HypovolemicHypovolemic ShockShockBut whyBut why

The body will make whatever adjustsments it can to The body will make whatever adjustsments it can to maintain….maintain….

AdequateAdequate CardiacCardiac

OutputOutput

Brain and heart perfusions remain Brain and heart perfusions remain near normalnear normal while while other less critical organ systems are, in proportion to the other less critical organ systems are, in proportion to the blood volume deficit, stressed by ischemia.blood volume deficit, stressed by ischemia.

Hypovolemic ShockHypovolemic Shock2. Uncompensated:2. Uncompensated:

20-40% loss of blood volume20-40% loss of blood volume

Decrease in BPDecrease in BP

TachycardiaTachycardia

HypovolemicHypovolemic ShockShockThe body’s response:The body’s response:

Uncompensated shockUncompensated shockThe intravascular volume deficit exceeds the The intravascular volume deficit exceeds the

capacity of vasoconstrictive mechanisms to capacity of vasoconstrictive mechanisms to maintain systemic perfusion pressure.maintain systemic perfusion pressure.

Increased cardiac outputIncreased cardiac output Increased respirationIncreased respirationSodium retentionSodium retention

Hypovolemic ShockHypovolemic Shock3. Lethal exsanguination:3. Lethal exsanguination:

40% loss of blood volume40% loss of blood volume

Profound hypotension and inability to Profound hypotension and inability to perfuse vital organsperfuse vital organs

Hypovolemic ShockHypovolemic ShockThe body’s response:The body’s response:

Lethal exsanguination:Lethal exsanguination:– ObtundedObtunded– Severe hypotensionSevere hypotension– Severe tachycardiaSevere tachycardia– Cold, ClammyCold, Clammy– DeathDeath

Hypovolemic ShockHypovolemic ShockCaveats…Caveats…

AthletesAthletesPregnancyPregnancyExtremes of ageExtremes of ageMedicationsMedicationsHematocrit/HemoglobinHematocrit/Hemoglobin

HypovolemicHypovolemic ShockShockManagement:Management:

ABCs of trauma (AIRWAY is ABCs of trauma (AIRWAY is always first!)always first!)

Control hemorrhage (splint the Control hemorrhage (splint the limb!!)limb!!)

Obtain IV access and resuscitate Obtain IV access and resuscitate with fluids and blood with fluids and blood

– 2 liters crystalloid for adults2 liters crystalloid for adults– 20 cc/kg crystalloid x 2 for kids20 cc/kg crystalloid x 2 for kids

Blood vs. Crystalloid??Blood vs. Crystalloid??

Long term critical care Long term critical care managementmanagement

Hypovolemic ShockHypovolemic Shock

Your management goals AFTER securing the Your management goals AFTER securing the ABCs:ABCs:

• STOP THE BLEEDING!STOP THE BLEEDING!

• RESTORE VOLUME!RESTORE VOLUME!

• CORRECT ANY ELECTROLYTE/ACID-BASE CORRECT ANY ELECTROLYTE/ACID-BASE DISTURBANCES!DISTURBANCES!

Hypovolemic ShockHypovolemic Shock

Hypovolemic ShockHypovolemic Shock

Hypovolemic ShockHypovolemic ShockVolume Resuscitation ~ What are my goals?Volume Resuscitation ~ What are my goals?

1. Rapid Responder1. Rapid Responder– Give 500cc-1 Liter crystalloid Give 500cc-1 Liter crystalloid rapid rapid

improvement of BP/HR/Urine outputimprovement of BP/HR/Urine output– < 20% blood loss< 20% blood loss– Surgery consultSurgery consult

Hypovolemic ShockHypovolemic ShockVolume Resuscitation ~ What are my goals?Volume Resuscitation ~ What are my goals?

2.Transient Responder2.Transient Responder– Give 500cc-1 Liter crystalloid Give 500cc-1 Liter crystalloid improves improves

briefly then deterioratesbriefly then deteriorates– 20-40% blood loss20-40% blood loss– Continue crystalloid infusion +/- BloodContinue crystalloid infusion +/- Blood– Surgery consultSurgery consult

Hypovolemic ShockHypovolemic ShockVolume Resuscitation ~ What are my goals?Volume Resuscitation ~ What are my goals?

3. Non Responder3. Non Responder– Give 2 Liters crystalloid/ 2 units Blood Give 2 Liters crystalloid/ 2 units Blood no no

responseresponse– > 40% blood loss> 40% blood loss– STAT Surgery consult!STAT Surgery consult!

Hypovolemic ShockHypovolemic ShockIs my volume resuscitation Is my volume resuscitation

adequate/inadequate?adequate/inadequate?

Urine output Urine output Vital signsVital signsSkin perfusionSkin perfusionPulse OximetryPulse OximetryAcidemia??Acidemia??

Septic ShockSeptic ShockAn exaggerated endogenous inflammatory An exaggerated endogenous inflammatory

response to invasive infection leading to:response to invasive infection leading to:

circulatory collapsecirculatory collapse multiple organ failuremultiple organ failure deathdeath

Septic ShockSeptic Shock

Septic ShockSeptic ShockMortalityMortalityover 35% (sepsis with hypotension)over 35% (sepsis with hypotension)

45% (sustained septic shock)45% (sustained septic shock)

SepticSeptic ShockShockManagement:Management: Identify and treat the infectious sourceIdentify and treat the infectious source

eg – simple incision & drainage? eg – simple incision & drainage? Exploratory laparotomy?Exploratory laparotomy?

Amputation?Amputation?

Volume resuscitationVolume resuscitation

Restoration of perfusion pressure (may need Restoration of perfusion pressure (may need pressors!)pressors!)

Cardiogenic ShockCardiogenic ShockAcute hypotensionAcute hypotension

low cardiac output low cardiac output inadequate LV outflow inadequate LV outflow

Poor end organ perfusion!Poor end organ perfusion!

Cardiogenic ShockCardiogenic ShockCauses most likely to see on the surgery wards:Causes most likely to see on the surgery wards:

Acute MIAcute MIArrhythmia (A. fib)Arrhythmia (A. fib)Cardiac Contusion Cardiac Contusion Cardiac TamponadeCardiac TamponadeMassive Pulmonary EmbolismMassive Pulmonary EmbolismDecompensated Congestive Heart FailureDecompensated Congestive Heart Failure

ShockShock

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