Surgery Essentials: Mastering Preoperative Assessment and Care

Preoperative care is the foundation of successful surgical outcomes. A thorough preoperative assessment identifies potential risks, optimizes patient condition, and ensures informed consent. This comprehensive guide covers essential principles every medical student and junior doctor must master for safe perioperative care and excellent clinical practice.

The Preoperative Assessment Framework

1. Comprehensive History Taking

Current Condition: Understand the indication for surgery, symptom duration, severity, and impact on daily activities. Document any emergency red flags that might affect timing or approach.

Past Medical History: Screen for conditions that increase surgical risk:

Cardiovascular disease (MI, heart failure, arrhythmias)
Respiratory disease (COPD, asthma, OSA)
Diabetes mellitus and glycemic control status
Renal or hepatic impairment
Neurological disorders (stroke, seizures)
Bleeding disorders or thrombophilia

Previous Surgeries: Document all prior operations, anesthetic complications, difficult intubation, PONV (postoperative nausea/vomiting), or prolonged recovery. Family history of anesthetic problems like malignant hyperthermia is crucial.

Medications: Review all current medications including over-the-counter and herbal supplements. Key considerations:

Anticoagulants/antiplatelets (timing of cessation/bridging)
Antihypertensives (continue most, hold ACE-I/ARBs on surgery day)
Diabetic medications (adjust insulin/oral agents)
Steroids (stress dose coverage if chronic use)
Immunosuppressants (infection risk assessment)

For drug interactions, see our Pharmacology Guide.

2. Functional Capacity Assessment

Functional capacity predicts perioperative risk. Use the Metabolic Equivalent (MET) system:

Excellent (>10 METs): Running, heavy labor - low risk
Moderate (4-10 METs): Climbing stairs, housework - moderate risk
Poor (<4 METs): Minimal activity tolerance - high risk

Patients unable to walk 2 blocks or climb 2 flights of stairs without symptoms need further cardiac evaluation.

Risk Stratification Tools

ASA Physical Status Classification

ASA I: Healthy patient, no systemic disease
ASA II: Mild systemic disease (controlled HTN, smoking)
ASA III: Severe systemic disease (poorly controlled DM, COPD)
ASA IV: Severe disease threatening life (recent MI, sepsis)
ASA V: Moribund patient not expected to survive without surgery
ASA VI: Brain-dead patient for organ donation
E suffix: Emergency surgery (increases risk)

Higher ASA scores correlate with increased perioperative morbidity and mortality. Learn more at ASA Guidelines.

Cardiac Risk Assessment

Revised Cardiac Risk Index (RCRI): Identifies patients at risk for cardiac complications:

High-risk surgery (intraperitoneal, intrathoracic, vascular)
Ischemic heart disease
History of congestive heart failure
History of cerebrovascular disease
Diabetes requiring insulin
Preoperative creatinine >2 mg/dL

Each factor = 1 point. 0 points = 0.4% risk, 1 point = 1%, 2 points = 2.4%, ≥3 points = 5.4% risk of major cardiac events. For more on cardiovascular assessment, visit ACC Clinical Guidelines.

Essential Preoperative Investigations

Laboratory Tests

Routine for all patients:

Complete Blood Count (anemia, infection, thrombocytopenia)
Blood group and typing (cross-match if blood loss expected)
Coagulation profile (PT/INR, aPTT) if bleeding risk

Condition-specific:

Renal function (urea, creatinine, electrolytes) - age >65, renal disease, cardiac disease
Liver function tests - hepatic disease, alcohol abuse
HbA1c - diabetic patients (target <8% for elective surgery)
Pregnancy test - women of childbearing age

Imaging Studies

Chest X-ray: Age >60, cardiopulmonary disease, malignancy
ECG: Age >40-50, cardiovascular risk factors, symptoms
Echocardiography: Symptomatic valve disease, heart failure
Pulmonary function tests: Thoracic surgery, severe COPD

Patient Optimization Strategies

Cardiovascular Optimization

Hypertension: Target BP <140/90, continue beta-blockers
Recent MI/stent: Delay elective surgery (bare-metal stent 6 weeks, drug-eluting 12 months)
Heart failure: Optimize volume status, consider diuretics
Arrhythmias: Control rate, correct electrolytes

Respiratory Optimization

Smoking cessation (ideally 8 weeks before, minimum 24-48 hours)
Optimize bronchodilators and steroids for COPD/asthma
Treat active respiratory infections (delay if possible)
Consider incentive spirometry training preoperatively

Metabolic Control

Diabetes: HbA1c <8%, avoid hypoglycemia, adjust insulin regimen
Thyroid: Achieve euthyroid state before elective surgery
Nutritional: Correct severe malnutrition, consider preoperative nutrition support

Preoperative Fasting Guidelines

Follow the "2-4-6 Rule" to reduce aspiration risk while avoiding dehydration:

Clear fluids: Up to 2 hours before surgery
Breast milk: Up to 4 hours before surgery
Light meal: Up to 6 hours before surgery
Heavy/fatty meal: Up to 8 hours before surgery

These guidelines reduce gastric volume and acidity while maintaining hydration. For more details, see ASA Practice Guidelines.

Antibiotic Prophylaxis

Surgical site infections increase morbidity and costs. Prophylactic antibiotics should be:

Given within 60 minutes before incision (120 min for vancomycin/fluoroquinolones)
Appropriate spectrum for expected pathogens
Redosed if surgery >2 half-lives or significant blood loss
Discontinued within 24 hours post-op (cardiac surgery 48 hours max)

Common regimens:

Clean procedures: Usually not needed unless prosthetic material
Clean-contaminated: Cefazolin 2g IV
GI/colorectal: Cefazolin + metronidazole or cefoxitin
MRSA risk: Add vancomycin to regimen

Venous Thromboembolism Prophylaxis

Assess VTE risk using validated tools (Caprini, Rogers scores). Stratify and implement:

Low risk: Early mobilization, adequate hydration

Moderate risk: Mechanical prophylaxis (compression stockings, intermittent pneumatic compression)

High risk: Pharmacological prophylaxis (LMWH, unfractionated heparin) + mechanical

Continue prophylaxis until fully mobile or hospital discharge. Some high-risk patients need extended prophylaxis (up to 4 weeks for cancer/orthopedic surgery).

Informed Consent

Valid consent requires:

Capacity: Patient can understand and retain information
Information: Nature of procedure, benefits, risks, alternatives
Voluntariness: No coercion or undue pressure

Discuss common and serious risks specific to the procedure. Document the conversation thoroughly. For complex cases, involve family members (with patient permission).

Day-of-Surgery Checklist

Confirm patient identity, procedure, and site (use WHO checklist)
Mark surgical site if laterality involved
Verify NPO status and last oral intake
Remove jewelry, dentures, contact lenses
Ensure IV access established
Review medication administration (which held, which given)
Confirm blood products available if needed
Complete surgical safety checklist (sign-in, time-out, sign-out)

Special Populations

Elderly Patients

Assess cognitive function and delirium risk
Review polypharmacy and drug interactions
Evaluate frailty and functional dependence
Plan for postoperative delirium prevention

Pediatric Patients

Parental involvement in consent and preparation
Age-appropriate fasting (shorter times for infants)
Behavioral preparation and anxiety reduction
Temperature regulation (higher surface area:volume)

Pregnant Patients

Defer elective surgery until postpartum
Second trimester safest for essential surgery
Monitor fetal heart rate, involve OB team
Left lateral tilt positioning (after 20 weeks)

For obstetric considerations, see our Obstetrics Guide.

External Resources

Conclusion

Thorough preoperative assessment and optimization are critical for patient safety and surgical success. A systematic approach identifying and mitigating risks improves outcomes and reduces complications. Regular practice and adherence to evidence-based guidelines ensure high-quality perioperative care. Test your knowledge with our Question Bank and explore more surgical topics in our blog section.