PreoperativePreoperative Evaluation and Evaluation and

MedicationMedication

Learning AimsLearning AimsGoals of preoperative evaluation

What we do during preoperative evaluation

Airway evaluationASA classificationFasting protocols

Learn From A CaseLearn From A Case A 24-year-old healthy male was scheduled for an laparoscopic cholecystectomy. The induction of anesthesia was uneventful, the anesthesia was maintained with sevoflurane and fentanyl. 30 minutes after surgery, the EtCO2 rose to 70, and the temperature rose to above 40oC

Q: what happened? What’s the problem with the anesthesia?

After asking his family history, it showed that his sister was died during a minor surgery ten years ago, because of unknown reason, manifested with “high fever”, “shock”, and “muscle spasm” etc.!

What’s the problem of our practice of anesthesia?

Goals of Preoperative Goals of Preoperative evaluationevaluationThe preoperative evaluation consists of gathering information about the patient and formulating an anesthetic plan.

The overall objective is reduction of perioperative morbidity and mortality.

Inadequate preoperative planning and errors in patient preparation are the most common causes of anesthetic complications

Anesthesia and elective surgery should not proceed until the patient is in optimal medical conditions

If any procedure is performed without the patient’s consent, the physician may be liable for assault and battery

ROUTINE PREOPERATIVE ROUTINE PREOPERATIVE ANESTHETIC EVALUATIONANESTHETIC EVALUATIONHistory◦Current problem◦Other known problems◦Medication History

Allergies Drug intolerances Present therapy Non therapeutic

◦Previous anesthetics, operation◦Family history◦Review organ systems◦Last oral intake

ROUTINE PREOPERATIVE ROUTINE PREOPERATIVE ANESTHETIC EVALUATIONANESTHETIC EVALUATIONPhysical examination◦Vital signs◦Airway◦Heart◦Lungs◦Extremities◦Neurological examination

ANESTHETIC PLANANESTHETIC PLANPremedicationsType of Anesthesia: General Anesthesia

• Airway management• Induction• Maintenance

ANESTHETIC PLANANESTHETIC PLANRegional Anesthesia◦Technique◦Agent

Monitored Anesthesia Care (MAC)◦Supplemental oxygen◦Sedation

ANESTHETIC PLANANESTHETIC PLANIntra-operative management◦Monitoring◦Positioning◦Fluid management◦Special techniques

ANESTEHTIC PLANANESTEHTIC PLANPost-operative management◦Pain control◦Intensive care

Postoperative ventilation Hemodynamic monitoring

SYSTEMS APPROACHASYSTEMS APPROACHAAirway Basic concern of the anesthesiologist is always the patient’s airway

InductionMaintenanceMuscle Relaxation

COMPNENTS OF THE AIRWAY COMPNENTS OF THE AIRWAY PHYSICAL EXAMINATIONPHYSICAL EXAMINATION Length of upper incisors Condition of the teeth Relation of maxillary and mandibular incisors

during normal jaw closure Ability to protrude or advance lower incisors in

front of upper incisors Interincisor distance 3FB Tongue size Visibility of uvula Shape of palate Compliance of mandibular space Thyromental distance with head in maximum

extension 6cm Length of neck: mentosternal distance 15cm Thickness of neck Range of motion of head and neck Facial hair

MALLAMPATI MALLAMPATI CLASSIFICATIONCLASSIFICATION

Soft palateFaucesUvulapillars

Soft palateFaucesUvula

Soft palateUvula base

Hard palate only

Difficult intubationDifficult intubationMouth opening less than 3 cmLimitation of neck movementMicrognathiaMacroglossiaProtrusion of teethShort neckMorbid obesityTumor in the face and neck

AMERICAN SOCIETY OF AMERICAN SOCIETY OF ANESTHESIA (ASA) PHYSICAL ANESTHESIA (ASA) PHYSICAL STATUS CLASSIFICATIONSTATUS CLASSIFICATION

Purpose of ASA Purpose of ASA classificationclassification

Class Mortality Rate1 0.06-0.08%2 0.27-0.4%3 1.8-4.3%4 7.8-23%5 9.4-51%

SYSTEM APPROACHSYSTEM APPROACHPulmonary Pulmonary complication remain a major cause of morbidity and mortality for patients undergoing surgery and anesthesia

Preoperative risk factors Preoperative risk factors for pulmonary complicationsfor pulmonary complicationsThoracic and upper abdominal surgeryPreoperative history of chronic obstructive pulmonary disease

Preoperative purulent productive coughAnesthesia time greater than 3 hoursHistory of cigarette smokingAge older than 60 yearsObesityPoor preoperative state of nutritionSymptoms of respiratory diseaseAbnormal findings upon physical examination

Abnormal findings on chest radiographs

PULMONARYPULMONARYPerioperative pulmonary complications include: atelectasis, pneumonia, bronchitis, bronchospasm, hypoxemia, exacerbation of CPOD, and respiratory failure requiring mechanical ventilation

The site and type of surgery are the strongest predictors of complications

PULMONARYPULMONARYPatient related factors Patient with pre-existing pulmonary disease should include assessment of the type and severity of the disease, as well as the reversibility

PULMONARYPULMONARYTobacco◦Smoking increase carboxyhemoglobin levels, decrease ciliary function and increase sputum production and stimulation of CV system 2nd to nicotine

◦Cessation of smoking for 2 days◦Cessation for 4-8 weeks to reduce rate of postoperative pulmonary complications

◦Administer a bronchodilator such as albuterol preoperatively

PULMONARYPULMONARYAsthma◦During interview important to elicit information regarding inciting factor, severity, reversibility, and current status.

◦Frequency of using bronchodilators, hospitalization for asthma and requirement for systemic steroids

◦Perioperative steroids as prophylaxis for severe asthmatic

PULMONARYPULMONARYObstructive Sleep Apnea◦Obstruction of upper airway during sleep leading to episodic oxygen desaturation and hypercarbia

◦Propensity for airway collapse and sleep deprivation, patients are susceptible to respiratory depressant and airway effects of sedatives, narcotics and inhaled anesthetics

PULMONARYPULMONARYContinue medicationAerosol medication before surgeryRisk reduction of pulmonary complication◦Smoking cessation◦Education of lung expansion maneuver and deep breath exercise

◦Treatment of obstruction◦Antibitotic ◦hydration

SYSTEM APPROACHSYSTEM APPROACHCardiovascular preoperative evaluation◦Clinical risk indices◦Surgical procedure◦Exercise tolerance

Weighting of Cardiac Weighting of Cardiac Risk FactorsRisk Factors

Simplified algorithm for Simplified algorithm for cardiovascular evaluation of cardiovascular evaluation of patients for non cardiac surgerypatients for non cardiac surgery

CARDIAC RISK STRATIFICATION FOR CARDIAC RISK STRATIFICATION FOR NONCARDIAC SURGICAL PROCEDURES IN NONCARDIAC SURGICAL PROCEDURES IN PATIENTS WITH KNOWN CADPATIENTS WITH KNOWN CAD

High (reported cardiac risk >5%)◦Emergent major operation, particularly in elderly, aortic and other major vascular peripheral vascular

◦Anticipated prolonged surgical procedures associated with large fluid shifts and blood loss

Intermediate (reported cardiac risk<5%)◦Carotid enarterectomy◦Head and neck◦Intraperitoneal and intrathoracic◦Orthopedic◦Prostate

Low (reported cardiac risk <1%)◦Endoscopic procedures◦Cataract and breast

Exercise tolerance◦4METs: walk at 6km/hr, run short distance, heavy work around house, golf, bowling, dancing

CARDIOVASCULARCARDIOVASCULARCardiovascular test◦Electorcardiogram information of patient’s myocardium and coronary circulation

◦Abnomal Q waves in high risk paitent are highly suggesitve of past MI

◦The risk of reinfarction during an elective procedure performed within 3 months after a myocardial infarction exceeds 30%, while the reinfarction rate decreases to 4.5% after 6 months

SYSTEM APPROACHSYSTEM APPROACHEndocrine system◦Diabetes mellitus

Most common endocrinenopathy Hyperglycemia, blood glucose>200mg/dl

DM increase risk of CAD, hypertension, congestive heart failure and perioperative MI

At intermediate risk

Diabetes MellitusDiabetes MellitusPerioperative stress may increase serum glucose concentration secondary to the release of cortisol and catecholamine

Control of glucose within a range of 100-150mg/dl

Administer insulin in the form of infusion or regular infusion

Thyroid and Thyroid and Parathyroid DiseaseParathyroid DiseaseHistory and clinical manifestationThyoid function test more sensitive◦Thyroid-stimulating hormone (TSH)◦Thyrotropin◦Thyroxine (T4)◦Triiodothyronine (T3)

Hyperparathyroidism usually have hypercalcemia, indicating the need of serum calcium level monitoring

PREOPERATIVE LABORATORY PREOPERATIVE LABORATORY TESTINGTESTING

Recommendations for patient-Recommendations for patient-specific baseline testing before specific baseline testing before anestheisaanestheisa

Complete Blood Count and Complete Blood Count and Hemoglobin concentrationHemoglobin concentrationBaseline hematocrit is indicated in any procedure with a risk of blood loss

Hemoglobin level of 7g/dl is acceptable in patient without systemic disease

In patient with systemic disease signs of inadequate systemic oxygen delivery (tachypnea and tachydia) are indication for transfusion

ElectrolytesElectrolytesCreatinine and glucose has been recommended in older patient

Blood urea nitrogen and creatinine are indicated in patient with systemic disease or on medication that affect kidney

Patient has kidney disease may has hyperkalemia

Coagulation studiesCoagulation studiesHave significant impact on the surgical procedure and perioperative management

PT and aPTT analysis are indicated in patient with history of bleeding problems

Bleeding time advocated to determining the presence of qualitative platelet defect

Avoid regional anesthesia in patient with clinical bleeding diathesis

Pregnancy testingPregnancy testingPregnancy testing should be limited to female patient who believe they are pregnant or cannot tell if they are pregnant

To avoid specific agent that may harmful to the fetus

Chest X-RayChest X-RayCan identify abnormalities that may lead to delay or cancellation of planned surgical procedure or modification of perioperative care

Pneumonia, pulmonary edema, pulmonary nodules or mediastinal mass

Preoperative MedicationPreoperative Medication

GoalsGoalsRelief of anxietySedationAmnesiaAnalgesiaDrying of airway secretionsPrevention of autonomic reflex responses

Reduction of gastric fluid volume and increase pH

Antiemetic drugReduction of anesthetic requirementFacilitation of smooth induction of anesthesia

Prophylaxis against allergic reaction

Anesthetic managementAnesthetic managementPreoperative Psychological preparation

Preoperative medicine

Psychological Psychological preparationpreparationPreoperative visit and interview with patient and family members

Explain anticipated events and the proposed anesthetic management in an effort to reduce anxiety and allay apprehension

An informative and comforting preoperative visit may replace many milligram of depressant medication

Preoperation Preoperation medicationmedicationPatient condition, patient physical status and age must be considered

Surgical procedure and its duration are important factors

Must know patient weightTime and route of administration is important

Sedatives-Hypnotics and Sedatives-Hypnotics and TranquilizersTranquilizersBenzodiazepines anxiolysis, amnesia, and sedation

site of actions in CNS, little depression of ventilation and CV

wide therapeutic index with low toxicities

OpioidsOpioidsThe analgesic properties and respiratory depressant effects of opioids usually go hand in hand. The decrease in the carbon dioxide drive at the medullary respiratory center may be prolonged. Consider supplement oxygen for patient receiving opioids premedications

Nausea and vomitingCholedochoduodental sphicter spasm. Not with fentanyl and meperidine

Preanesthesia Medication Preanesthesia Medication InstructionInstruction

Antidepressant, antianxiety, and psychiatric medications should be continued on the day of surgery

Antihypertensives◦Generally to be continued◦Consider discontinuing ACEI or ARB 12-24 hr before surgery

Aspirin◦Continue on the day of surgery

Patients with known vascular disease Patients with drug-eluting stents for <12 months

Patients with bare metal stents for < 1 month Before cataract surgery Before vascular surgery Taken for secondary prophylaxis

◦Discontinue 5-7 days before surgery If risk of bleeding > risk of thrombosis For surgeries with serious consequences from bleeding

Taken only for primary prophylaxis

Clopidogrel◦Continue on the day of surgery

Patients with drug-eluting stents for < 12 months

Patients with bare metal stents for < 1 month

Before cataract surgery◦Patients not included in the group recommended for continuation

Warfarin◦Continue on the day of surgery

Cataract surgery with no bullbar block

◦Discontinue 5 days before surgery

Insulin◦Continue on the day of surgery

Type 1 diabetes: take 1/3 intermediate to long acting

Type 2 diabetes: take up to ½ of long acting

◦Discontinue Regular insulin Discontinue if blood glucose level < 100

Gastric Fluid pH and Gastric Fluid pH and VolumeVolumeSummary of fasting recommendations to reduce the risk of pulmonary aspiration

For healthy adult with no risk of aspiration, the following time of fasting is recommended:◦For solids 8 hours◦For light meal 6 hours ◦For fluids that are not clear 4hours (breast milk)

◦For clear fluids 2 hours

A CASEA CASEA healthy 24 man had a car accident at about 10 am after he his breakfast at 8am. His suffered from femur fracture and need for surgery. About 18 pm, after finished routine preoperative examinations, the patient was delivered to the OR.

Q: whether the fasting time of the patient is adequate? Why? What should we do?

Drugs for pharmacologic Drugs for pharmacologic premedication before premedication before AnesthesiaAnesthesia

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