What should be included in a comprehensive pre‑anaesthetic evaluation before surgery?

Pre-Anaesthetic Check-Up: Essential Components

A comprehensive pre-anaesthetic evaluation must include medical record review, patient interview, and focused physical examination (airway, lungs, heart with vital signs), with timing and testing guided by surgical invasiveness and patient disease severity. 1

Core Components of Pre-Anaesthetic Assessment

Medical Record Review

The evaluation begins with assessment of readily accessible medical records, which must document: 1

• Current diagnoses with specific attention to cardiovascular disease (hypertension, previous myocardial infarction), pulmonary disease (asthma, COPD, smoking history), and renal dysfunction 1, 2
• Complete medication list including dosing, timing, potential drug interactions, and medications requiring perioperative adjustment (anticoagulants, antihypertensives, insulin) 3
• Previous anesthetic complications including airway difficulties, malignant hyperthermia, prolonged paralysis, or adverse drug reactions 3, 2
• Cardiac rhythm management devices (pacemakers/ICDs) with device type, pacemaker dependency status, and recent function check within 3-6 months 3, 4

Patient Interview: Critical History Elements

Cardiovascular assessment must identify: 2, 5

• Chest pain, dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea
• Exercise tolerance (quantify in metabolic equivalents: can the patient climb two flights of stairs?)
• History of arrhythmias, syncope, or palpitations

Pulmonary screening requires asking about: 3, 2

• Chronic cough, sputum production, wheezing
• Obstructive sleep apnea symptoms: snoring, witnessed apneic episodes, frequent arousals, morning headaches, daytime somnolence 3
• Baseline oxygen saturation measurement 3

Allergy history must distinguish: 3

• True IgE-mediated anaphylactic reactions versus non-allergic adverse effects
• Latex allergy (high-risk groups: atopy, spina bifida, multiple surgeries, healthcare workers, fruit allergies to banana/chestnut/avocado) 3
• Drug allergies with specific reaction descriptions

Medication reconciliation includes: 3

• Prescription medications with exact dosing
• Over-the-counter medications
• Herbal supplements (St John's wort, ginkgo, ginger, ginseng, garlic, kava, valerian can prolong sedation via CYP450 inhibition) 3
• Illicit drug use in adolescents/adults 3

Focused Physical Examination

At minimum, the examination must assess: 1

Airway evaluation (100% consensus): 1

• Mouth opening (interincisor distance >3 cm)
• Mallampati classification
• Thyromental distance (>6 cm)
• Neck mobility and circumference
• Presence of beard, prominent teeth, receding mandible
• Nasopharyngeal characteristics, tonsil size, tongue volume 3

Pulmonary examination (88% consensus): 1

• Auscultation of both lung fields for wheezes, crackles, decreased breath sounds
• Respiratory rate and pattern
• Use of accessory muscles

Cardiovascular examination (81% consensus): 1

• Heart rate, rhythm, blood pressure (bilateral if vascular disease suspected)
• Auscultation for murmurs, gallops, irregular rhythms
• Peripheral pulses and edema
• Jugular venous distension

Musculoskeletal assessment: 3

• Osteoarthritis, kyphoscoliosis, fixed flexion deformities affecting positioning

Timing of Pre-Anaesthetic Evaluation

High Surgical Invasiveness

Perform evaluation prior to day of surgery (89% consultant consensus, 75% ASA member consensus): 1

• Initial record review, patient interview, and physical examination must occur before surgery day
• This applies regardless of patient disease severity for highly invasive procedures

Medium Surgical Invasiveness

Evaluation may occur on or before day of surgery (61% ASA member consensus): 1

• Consultants prefer prior to surgery day (58%), but majority of practicing anesthesiologists accept same-day evaluation for low-severity patients

Low Surgical Invasiveness

Evaluation acceptable on day of surgery (59-69% consensus): 1

• For patients with low disease severity undergoing minimally invasive procedures

Critical caveat: Patients with high severity of disease require evaluation prior to surgery day regardless of surgical invasiveness 1

Selective Preoperative Testing (Not Routine)

Routine preoperative tests do not contribute meaningfully to perioperative management and should be avoided. 1 Testing must be selective based on clinical indications: 1

Complete Blood Count (CBC)

Order when: 3

• Diseases increasing anemia risk (chronic kidney disease, malignancy, inflammatory bowel disease)
• History of anemia or bleeding disorders
• Anticipated significant perioperative blood loss
• Hip fracture patients (40% have preoperative anemia) 3
• Consider transfusion if Hb <9 g/dL, or <10 g/dL with ischemic heart disease 3

Electrocardiogram (ECG)

Order for: 1

• Men >60 years or women >65 years (10% 10-year coronary event risk)
• Known cardiovascular disease (hypertension, coronary artery disease, heart failure, arrhythmias)
• Diabetes mellitus
• Symptoms suggesting cardiac disease
• Not indicated for asymptomatic young patients undergoing low-risk surgery

Electrolytes and Creatinine

Order for: 3

• Chronic kidney disease
• Medications predisposing to electrolyte abnormalities (diuretics, ACE inhibitors, digoxin)
• Diabetes mellitus
• Liver disease

Glucose Testing

Order for: 3

• Known diabetes
• High risk of undiagnosed diabetes (obesity, metabolic syndrome, family history)

Coagulation Studies (PT, aPTT, Platelets)

Order for: 1, 3

• History of bleeding disorders
• Liver dysfunction
• Renal dysfunction
• Current anticoagulant therapy
• Insufficient evidence to recommend routine testing before regional anesthesia 1

Chest X-Ray and Pulmonary Function Tests

Not routinely indicated unless: 5

• New or unstable cardiopulmonary symptoms
• Planned thoracic surgery requiring lung resection assessment

Special Populations

Pediatric Patients

Additional requirements: 3

• Document gestational age (preterm infants retain apnea risk)
• Weight-based medication dosing
• Developmental delays or behavioral issues
• Family history of pseudocholinesterase deficiency or muscular dystrophy
• Pregnancy testing for females ≥12 years (1% of menarchal females are pregnant)
• Immunization status

Patients with Cardiac Devices

Must establish: 3, 4

• Device type (pacemaker vs. ICD)
• Pacemaker dependency status
• Device function check within 3-6 months
• Plan for electromagnetic interference management
• Consider asynchronous mode (VOO/DOO) for pacemaker-dependent patients 4

Patients with Congenital Heart Disease

Manage at specialized centers unless absolute emergency: 3

• Prior Fontan procedure
• Severe pulmonary arterial hypertension
• Cyanotic congenital heart disease
• Complex CHD with residua

Documentation Requirements

Essential documentation includes: 1, 3

• ASA physical status classification
• Airway assessment findings
• Cardiac device information and perioperative plan
• Allergy status (especially latex and drug allergies)
• Medication reconciliation with perioperative continuation/discontinuation plan
• Fasting status verification
• Informed consent

Common Pitfalls to Avoid

1. Ordering routine tests without clinical indication wastes resources and does not improve outcomes 1, 5
2. Failing to identify pacemaker dependency can lead to asystole 4
3. Inadequate airway assessment is the most preventable cause of anesthetic morbidity 1
4. Ignoring functional capacity (inability to climb two flights of stairs indicates <4 METs and higher cardiac risk) 2, 6
5. Last-minute consultations prevent adequate optimization; high-risk patients need evaluation well before surgery day 1, 6
6. Dismissing herbal supplements as irrelevant when they significantly affect drug metabolism 3