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?

History of gastric bypass surgery

A 66-year-old female with hypertension and a recent history of acute ST-elevation myocardial infarction (STEMI) 6 days previous, treated with percutaneous transluminal angioplasty (PTA), presents with sudden onset chest pain, shortness of breath, diaphoresis, and syncope. Vitals are temperature 37°C (98.6°F), blood pressure 80/50 mm Hg, pulse 125/min, respirations 12/min, and oxygen saturation 92% on room air. On physical examination, the patient is pale and unresponsive. Cardiac exam reveals tachycardia and a pronounced holosystolic murmur loudest at the apex and radiates to the back. Lungs are clear to auscultation. Chest X-ray shows cardiomegaly with clear lung fields. ECG is significant for ST elevations in the precordial leads (V2-V4) and low-voltage QRS complexes. Emergency transthoracic echocardiography shows a left ventricular wall motion abnormality along with a significant pericardial effusion. The patient is intubated, and aggressive fluid resuscitation is initiated. What is the next best step in management?

Immediate transfer to the operating room

Immediate cardiac catheterization

Intra-aortic balloon counterpulsation

Administer dobutamine 5-10 mcg/kg/min IV

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

"Can you tell me more about the symptoms you have been experiencing?"

"Does the diarrhea typically precede the constipation, or vice-versa?"

"Is the diarrhea foul-smelling?"

"Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"

"Are the symptoms worse in the morning or at night?"

A 66-year-old man with severe aortic stenosis (valve area 0.7 cm², mean gradient 55 mmHg) and Class III heart failure requires emergent hemicolectomy for perforated diverticulitis with peritonitis. He is hemodynamically stable on pressors. Cardiology states he is high-risk for valve replacement but could undergo TAVR in 2-3 weeks. The surgeon believes he needs surgery within 6-8 hours. Evaluate the management approach.

Proceed with colectomy under invasive monitoring with cardiology backup

Delay surgery, perform urgent TAVR, then colectomy in 2-3 weeks

Perform colostomy only under local anesthesia, defer resection

Medical management of perforation with antibiotics pending TAVR

Simultaneous TAVR and emergency colectomy in hybrid OR

Preoperative anesthesia evaluation for USMLE Step 1: High-Yield Surgery Lessons

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.

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 Class	Action	Timing / Notes
Antihypertensives
- Beta-blockers	Continue	Prevents rebound tachycardia/hypertension.
- ACEi / ARBs	Stop	Hold on the morning of surgery (risk of refractory hypotension).
Antiplatelets/Anticoagulants
- Aspirin / Clopidogrel	Stop	Hold 5-7 days prior, unless high cardiac risk.
- Warfarin	Stop	Hold 5 days prior; bridge if high thromboembolic risk.
- DOACs	Stop	Hold 2-3 days prior (depends on drug & renal function).
Diabetes Meds
- Oral agents	Stop	Hold morning of surgery (risk of hypoglycemia).
- Insulin	Adjust	Take half dose of long-acting insulin; hold short-acting.
Psychiatric Meds	Continue	Avoid 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.

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