Preoperative anesthesia evaluation

Preoperative anesthesia evaluation

Preoperative anesthesia evaluation

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ASA Classification - Status Check

  • ASA 1: Normal healthy patient.
  • ASA 2: Mild systemic disease (e.g., controlled HTN or DM, smoking, obesity). No functional limitations.
  • ASA 3: Severe systemic disease with functional limitations (e.g., stable angina, ESRD on dialysis, post-MI >3 months).
  • ASA 4: Severe systemic disease that is a constant threat to life (e.g., recent MI <3 months, sepsis, ARDS).
  • ASA 5: Moribund; not expected to survive without the operation.
  • ASA 6: Declared brain-dead; organ procurement.
  • Modifier E: Added for emergency surgery (e.g., ASA 2E).

⭐ The ASA classification is an independent predictor of perioperative morbidity and mortality. Each increasing class doubles the risk of adverse outcomes.

Airway Assessment - Open Sesame

Predicting a difficult airway is key to preventing a "can't intubate, can't ventilate" crisis.

📌 LEMON Method:

  • Look: External signs (e.g., small jaw, large tongue, facial trauma).
  • Evaluate: 3-3-2 Rule
    • Mouth Opening: > 3 fingers
    • Thyromental Distance: > 3 fingers
    • Hyoid-to-Thyroid: > 2 fingers
  • Mallampati Score: Assesses oral opening; higher class = more difficult.
  • Obstruction: Any signs of upper airway obstruction?
  • Neck Mobility: Limited C-spine movement is a red flag.

Mallampati Classification Diagram (Classes I-IV)

⭐ A Mallampati score of III or IV significantly increases the likelihood of a difficult intubation, as less of the pharyngeal structure is visible.

Cardiac Risk Stratification - Heart Smart

Assesses risk of Major Adverse Cardiac Events (MACE) in non-cardiac surgery using the Revised Cardiac Risk Index (RCRI). One point for each:

  • High-Risk Surgery: intraperitoneal, intrathoracic, suprainguinal vascular
  • Ischemic Heart Disease: hx of MI, + stress test, current angina, nitrates use
  • Congestive Heart Failure: hx of CHF, pulmonary edema, PND
  • Cerebrovascular Disease: hx of stroke or TIA
  • Diabetes Mellitus: requiring pre-op insulin
  • Chronic Kidney Disease: pre-op creatinine >2.0 mg/dL

⭐ Beta-blockers are recommended to be continued if the patient is already on them. Starting them perioperatively is not routinely recommended for beta-blocker naive patients unless there is a clear indication like untreated severe hypertension or symptomatic arrhythmia.

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Perioperative Medication - Stop or Go?

General Principle: Continue most essential medications, especially those for cardiovascular stability. Stop those that increase surgical risk (bleeding, hypotension).

Medication ClassActionTiming / Notes
Antihypertensives
  - Beta-blockersContinuePrevents rebound tachycardia/hypertension.
  - ACEi / ARBsStopHold on the morning of surgery (risk of refractory hypotension).
Antiplatelets/Anticoagulants
  - Aspirin / ClopidogrelStopHold 5-7 days prior, unless high cardiac risk.
  - WarfarinStopHold 5 days prior; bridge if high thromboembolic risk.
  - DOACsStopHold 2-3 days prior (depends on drug & renal function).
Diabetes Meds
  - Oral agentsStopHold morning of surgery (risk of hypoglycemia).
  - InsulinAdjustTake half dose of long-acting insulin; hold short-acting.
Psychiatric MedsContinueAvoid withdrawal syndromes.

High-Yield Points - ⚡ Biggest Takeaways

  • The ASA classification is a cornerstone for predicting perioperative risk.
  • The Mallampati score predicts the ease of intubation; higher classes mean more difficulty.
  • Use the RCRI to assess cardiac risk; recent MI, decompensated HF, and severe valve disease are major risks.
  • Advise smoking cessation at least 8 weeks pre-op to decrease pulmonary complications.
  • Continue β-blockers perioperatively; hold most anticoagulants based on procedure-specific bleeding risk.
  • Standard NPO guidelines: 2 hours for clear liquids, 6-8 hours for solids.

Practice Questions: Preoperative anesthesia evaluation

Test your understanding with these related questions

A 57-year-old man presents to his physician with dyspnea on exertion and rapid heartbeat. He denies any pain during these episodes. He works as a machine operator at a solar panels manufacturer. He has a 21-pack-year history of smoking. The medical history is significant for a perforated ulcer, in which he had to undergo gastric resection and bypass. He also has a history of depression, and he is currently taking escitalopram. The family history is unremarkable. The patient weighs 69 kg (152 lb). His height is 169 cm (5 ft 7 in). The vital signs include: blood pressure 140/90 mm Hg, heart rate 95/min, respiratory rate 12/min, and temperature 36.6℃ (97.9℉). Lung auscultation reveals widespread wheezes. Cardiac auscultation shows decreased S1 and grade 1/6 midsystolic murmur best heard at the apex. Abdominal and neurological examinations show no abnormalities. A subsequent echocardiogram shows increased left ventricular mass and an ejection fraction of 50%. Which of the options is a risk factor for the condition detected in the patient?

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Flashcards: Preoperative anesthesia evaluation

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EF < _____% and MI within _____ months are absolute contraindications to non-cardiac surgery

TAP TO REVEAL ANSWER

EF < _____% and MI within _____ months are absolute contraindications to non-cardiac surgery

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