Preanesthetic Assessment and Patient Preparation
Risk stratification and preparation
The Preanesthetic Assessment and Patient Preparation domain tests systematic risk assessment, airway prediction, fasting, medication management and informed consent. The exam expects ASA physical status, comorbidity optimization and a documented plan.
- ASA I: healthy; II: mild systemic disease; III: severe systemic disease; IV: severe disease with constant threat to life; V: moribund; VI: brain-dead organ donor. Emergency adds E.
- Airway screen: Mallampati (sitting, phonation, tongue protruded), mouth opening, thyromental distance, neck mobility, dentition, beard, obesity, prior difficult airway.
- Fasting: clear fluids 2 h; breast milk 4 h; infant formula and nonhuman milk 6 h; light meal 6 h; fatty or fried meal or meat 8 h. Clear fluids should not be withheld unnecessarily.
- Medications: continue beta-blockers, statins and most antihypertensives; hold ACE inhibitors or ARBs if hypotension risk is high; manage anticoagulants by bleeding risk and procedure; continue inhalers.
- Consent: capacity, risks, benefits, alternatives, questions answered.
Worked example
A 72-year-old with atrial fibrillation on warfarin has an INR of 3.0 for elective hernia repair. The reasoning: INR 3.0 is above the typical elective threshold, so proceed only after discussion; cancel and coordinate cardiology, because reversal exposes stroke risk and continuation exposes bleeding risk. For urgent surgery, vitamin K or prothrombin complex concentrate may be considered. The mark comes from recognizing competing risks, not from quoting one INR number.
Traps that cost marks
NPO after midnight is outdated and can cause dehydration. A high Mallampati score alone does not predict difficult mask ventilation. Do not label a patient ASA IV just because surgery is major. Do not forget obstructive sleep apnea, GERD and aspiration risk.