Preoperative Care

General Preoperative Evaluation

Basic evaluation

Preoperative care for elective surgical procedures is conducted in the outpatient setting.

Goals of the interview:

• To identify any current complaints
• To address hopes and expectations of planned surgery
• To relieve anxiety by answering questions
• To identify undiagnosed diseases
• To optimize pre-existing comorbidities

Medical history with emphasis on:

• Review of systems 
• Past medical history
• Past surgical history
• Medications

Physical examination:

• Vital signs
• Cardiovascular examination
• Respiratory examination 
• Surgery-related examination (e.g., suitability for positioning): assessment of comorbidities and their severity

Additional studies:

• CBC:
  • For patients > 65 years of age who are scheduled for major surgery
  • Preoperative anemia is associated with increased postoperative mortality.
• Basic metabolic panel:
  • Routine measurement of electrolytes, glucose, or liver enzymes is not indicated.
  • Determination of creatinine levels recommended for patients > 50 years of age who are scheduled for high- or intermediate-risk surgery
• Coagulation studies: not routinely indicated
• Pregnancy test: for all women of child-bearing age
• ECG: not indicated for healthy patients < 45 of age
• Chest X-ray: 
  • Not routinely indicated
  • Recommended for patients > 50 years of age scheduled for surgery for aortic aneurysm, or in the case of upper abdominal or thoracic surgery

Screening

Most healthy patients do not need additional preoperative evaluation.

The goal of screening is to identify patients with risk factors who may benefit from additional evaluation.

Specific factors that can influence postoperative outcomes:

• Age (minor risk factor)
• Medications
• Patient’s functional capacity (e.g., climbing stairs) using the metabolic equivalent task: 
  • 1 metabolic equivalent task: patient can complete basic daily activities such as using the bathroom and dressing
  • 4 metabolic equivalent tasks: the ability to walk up a flight of stairs or walk at 3–4 miles/hour (6.4 km/hour)
  • 4–10 metabolic equivalent tasks: heavy housework, climbing 2 flights of stairs consecutively, heavy lifting
  • > 10 metabolic equivalent tasks: strenuous sports activities such as swimming, tennis, and basketball 
• Obesity
• Smoking
• Illicit drug use
• Alcohol abuse
• Obstructive sleep apnea
• Personal or family history of anesthetic complications

Screening questionnaires:

• Identify patients with pre-existing medical conditions that may increase perioperative risk and need further evaluation.
• One of the effective questionnaires consists of 17 questions and includes questions on:
  • Functional capacity (climbing 2 flights of stairs)
  • Heart disease
  • Thyroid disease
  • Diabetes
  • Liver disease
  • Renal insufficiency
  • Seizures
  • Anesthetic complications
  • Asthma/bronchitis

Preoperative Cardiovascular Evaluation

Risk assessment and stratification

Patients with a history or symptoms suggestive of heart disease need further assessment. Multiple algorithms for risk assessment have been developed. The revised cardiac risk index (RCRI) is the most practical and frequently used tool:

• 1 surgery-specific risk factor: high-risk procedures:
  • Vascular surgery
  • Open intraperitoneal procedures
  • Intrathoracic procedures
• 5 patient-specific risk factors:
  • Ischemic heart disease
  • Heart failure
  • Cerebrovascular disease
  • Insulin-dependent diabetes mellitus
  • Preoperative serum creatinine ≥ 2.0 mg/dL
• Patient stratification:
  • Patients stratified as “low risk” have no risk factors.
  • Patients stratified as “high risk” have 1 or more risk factors.

Indications for further testing

Low-risk patients do not need further evaluation.

High-risk patients are classified based on functional capacity:

• Metabolic equivalent tasks ≥ 4: no further testing
• Metabolic equivalent tasks <4: 
  • Pharmacologic stress test is performed.
  • Coronary revascularization should be performed prior to surgery if results of the stress test warrant it.

Very high-risk patients:

• Defined as:
  • MI within 60 days of the planned procedure
  • Decompensated heart failure
  • Unstable angina
  • High-grade arrhythmias
  • Hemodynamically significant valve disease
• Very high risk of perioperative MI and cardiac death
• Need referral to a cardiologist and maximal optimization prior to procedure

Risk-reduction strategies

• Optimization of medical therapy:
  • Beta-blockers 
  • Statins
• Angiography and revascularization for patients with angina 
• Interventions on anatomic abnormalities such as valves

Preoperative Pulmonary Evaluation

Risk factors for postoperative pulmonary complications

• Age > 50 years
• Chronic obstructive pulmonary disease (COPD)
• Chronic heart failure (CHF)
• Current smoker
• Obstructive sleep apnea
• Low O₂ saturation
• Pulmonary hypertension
• Serum albumin < 3.5
• Functional dependence
• Poor general health status

Indications for pulmonary tests

• Chest X-ray: patients > 50 years of age scheduled for an upper abdominal or thoracic procedure
• Pulmonary function tests:
  • Dyspnea
  • Exercise intolerance
  • History of asthma or COPD, if the extent of impairment cannot be determined clinically
  • Patients undergoing lung resections
  • Findings with increased risk:
    • Forced expiratory volume in 1 sec (FEV₁) < 70% of the predicted value
    • Forced vital capacity (FVC) < 70% of the predicted value
    • FEV1/FVC ratio < 65%
• Arterial blood gas (ABG): not routinely indicated for preoperative pulmonary evaluation
• Cardiopulmonary exercise test (CPET):
  • To calculate the maximum O₂ uptake and anaerobic ventilatory threshold
  • Used in patients with abnormal pulmonary function tests who are scheduled to undergo lung resection
  • The 6-minute walk test is an in-office option that correlates the risk and severity of postoperative complications.

System-specific Evaluations

Hepatic evaluation

• Postpone elective surgeries in case of acute hepatitis. 
• In patients with chronic liver disease, risk assessment should be done based on the Child-Pugh classification and the model for end-stage liver disease.
  • Child-Pugh C (decompensated cirrhosis) or model for end-stage liver disease score > 15: Elective surgeries are contraindicated. 
  • Child-Pugh B (significant functional compromise) or model for end-stage liver disease score of 10–15: Surgeries may be performed, but with caution.
  • Child-Pugh A (well-compensated cirrhosis) or model for end-stage liver disease score < 10: Surgery is well tolerated.
• Complications of liver diseases (e.g., thrombocytopenia or decreased albumin levels) should be reversed prior to surgery, if possible.

Endocrine evaluation

• Diabetes mellitus:
  • HbA1c and a metabolic panel should be ordered for patients preoperatively.
  • Patients with diabetes mellitus should be early on the operating room schedule due to their nil per os status.
  • Regular insulin:
    • Should be held when patients are admitted prior to surgery and postoperatively when nil per os
    • Optimal serum glucose levels: 140–180 mg/dL
    • Monitored every 4 hours when nil per os
  • Long-acting insulin:
    • Administer ⅔ of the home dose on the night before surgery.
    • Administer half the home dose on the day of surgery.
• Adrenal suppression:
  • Chronic steroid therapy of > 5 mg prednisone daily for at least 3 weeks before surgery increases the risk for adrenal insufficiency during the perioperative period.
  • Moderate surgical stress:
    • 50 mg hydrocortisone IV bolus before the induction of anesthesia
    • 25 mg hydrocortisone every 8 hours for 24–48 hours
  • Major surgical stress:
    • 100 mg hydrocortisone IV bolus before the induction of anesthesia
    • 50 mg hydrocortisone every 8 hours for 24–48 hours
• Malnutrition: 
  • Nutritional support for 2 weeks prior to surgery for patients who are malnourished
  • Clinically significant weight loss:
    • > 10% over 6 months
    • > 5% over a 1-month period
  • Nutritional parameters:
    • Albumin
    • Prealbumin
    • Transferrin

Renal evaluation

• Preoperative creatinine > 2 mg/dL is an independent risk factor for postoperative cardiovascular complications.
• Patients with known renal dysfunction should be ordered:
  • ECG
  • Serum chemistry
  • CBC
• Patients on dialysis: Clarify when they were last dialyzed and check K⁺ levels preoperatively.

Hematologic evaluation

All patients should be asked about a history of bleeding disorders or the use of anticoagulants. Perioperative management differs significantly and is dependent on the indication and type of anticoagulant.

• Prosthetic heart valves:
  • High risk (recent stroke or transient ischemic attack (TIA) < 1 month; mitral valve): strongly recommend bridging with a short-acting agent such as heparin or enoxaparin sodium
  • Moderate or low risk (bileaflet aortic valve): Consider bridging.
• Chronic atrial fibrillation:
  • Bridging with enoxaparin sodium or heparin should be considered in all cases.
  • Bridging is strongly recommended in patients with TIA and rheumatic mitral valve disease
• Venous thromboembolism (VTE):
  • High risk (bridging strongly recommended):
    • VTE within 3 weeks of surgery
    • Active cancer
    • Antiphosopholipid antibody
  • Moderate risk (bridging should be considered):
    • VTE in the past 6 months
    • VTE with any interruption in anticoagulation
  • Low risk (no risk factors): optional bridging

Anesthesia Evaluation and Preoperative Preparation

Assessment of patient status

The American Association for Anesthesiologists classification system stratifies patients for postoperative outcomes based on health status:

• Class I: normal and healthy patient
• Class II: mild systemic disease
• Class III: severe systemic disease that limits activity
• Class IV: incapacitating disease that is a constant threat to life
• Class V: patient not expected to survive for 24 h regardless of surgical intervention

Airway evaluation

• To assess the ease of intubation and airway maneuvers 
• Assessed using the modified Mallampati score by looking into an open mouth

Antibiotic prophylaxis for surgical site infections

• 1st-generation cephalosporins (cefazolin) 
• Cefazolin + metronidazole for bowel surgery
• Allergy to penicillin: 
  • Vancomycin
  • Clindamycin

Preoperative fasting

• 8 hours prior to surgery: no fried or fatty foods or meat
• 6 hours prior to surgery: no nonhuman milk, infant formula, light meal
• 4 hours prior to surgery: no breast milk
• 2 hours prior to surgery: nil per os

Fluid replacement

Provide maintenance fluid on the morning of surgery and continue intraoperatively: 1.5 mL/kg/hour will meet the maintenance fluid requirements for most patients.

Medications