Pre-op Evaluation & Post-op Complications
A Step 2 CK-focused walkthrough of perioperative care: cardiac risk stratification (METs, RCRI, surgical timing), which drugs to hold or continue, and the postoperative-day timeline that pins down post-op fever and surgical complications with next-best-step management.
How the boards frame it
Pre-op evaluation on Step 2 CK is really cardiac risk stratification plus a short list of drugs to hold or continue — and the tested question is almost always "what's the next best step before clearing this patient?" Post-op complications are tested by timeline: the postoperative day (POD) hands you the diagnosis before the vignette even finishes.
Anchor every stem to two numbers — the patient's functional capacity (METs) before surgery, and the POD after it. Most correct "next step" answers are conservative: optimize what is reversible, delay elective surgery only when the delay changes outcomes, and never order a test whose result won't change management.
- Emergency surgery → operate now; risk-stratify and treat complications afterward.
- Active cardiac conditions (unstable angina, decompensated HF, significant arrhythmia, severe symptomatic valvular disease e.g. critical AS) → evaluate/optimize before elective surgery.
- Functional capacity ≥4 METs (climb 2 flights of stairs, walk up a hill) + asymptomatic → proceed, no further cardiac testing.
- <4 METs or unknown + elevated surgical/clinical risk → stress test only if the result will change management.
- RCRI (6 predictors): high-risk surgery, ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine >2.0 mg/dL.
- Timing of elective surgery: delay ≥60 days after MI; ≥30 days after a bare-metal stent; ≥6 months after a drug-eluting stent (minimum 3 months if surgery can't wait) — keep the patient on DAPT.
- Beta-blockers: continue if already taking them; do not start on the day of surgery (POISE trial: fewer MIs but more strokes and deaths).
- Continue: beta-blockers, statins, most antihypertensives (except below), inhalers, thyroid hormone.
- Hold morning of surgery: ACE inhibitors / ARBs and diuretics (intra-op hypotension / hypovolemia).
- Hold day of surgery: metformin and other oral hypoglycemics; give ½ dose of long-acting/basal insulin and hold short-acting.
- SGLT2 inhibitors: stop 3–4 days before (euglycemic DKA risk).
- Warfarin: stop ~5 days pre-op; bridge with heparin only if high thromboembolic risk (mechanical mitral valve, recent VTE, AF with prior stroke).
- Pulmonary complication risk ↑ with COPD, current smoking, upper-abdominal/thoracic surgery, advanced age, OSA → counsel smoking cessation (weeks ahead), incentive spirometry, early ambulation, lung-protective ventilation.
A 20-year-old undergoes appendectomy under general anesthesia with succinylcholine and a volatile agent. Minutes later there is a rising end-tidal CO2 (earliest, most sensitive sign), masseter then generalized muscle rigidity, tachycardia, and a rapidly climbing temperature.
Dx: Malignant hyperthermia (autosomal-dominant RYR1 mutation).
Next step: Immediately stop the triggering agents, give IV dantrolene, hyperventilate with 100% O2, begin active cooling, and treat hyperkalemia/acidosis. Watch for rhabdomyolysis and myoglobinuria afterward.
On POD 6 after a sigmoid colectomy with primary anastomosis, a patient develops fever, tachycardia, worsening abdominal pain, ileus, leukocytosis, and feculent or purulent drainage from the wound or drain.
Dx: Anastomotic leak.
Next step: NPO, IV fluids, broad-spectrum antibiotics, and CT of the abdomen/pelvis with water-soluble (oral/rectal) contrast to confirm and localize the leak. Return to the OR for washout ± diversion if there is diffuse peritonitis or hemodynamic instability; a small contained leak may be managed with drainage and antibiotics.
On POD 7 after a midline laparotomy, a patient reports a sudden gush of pink, serosanguinous ("salmon-colored") fluid from the incision, and the wound edges feel separated with a palpable "give."
Dx: Fascial (wound) dehiscence — the warning sign that precedes evisceration.
Next step: Cover the wound with sterile saline-moistened gauze, keep the patient supine and NPO, and arrange an urgent return to the OR for repair. If bowel is protruding (evisceration) → emergent operative closure.
- Wind (POD 1–2): atelectasis, pneumonia
- Water (POD 3–5): UTI (indwelling Foley)
- Walking (POD 4–6): DVT / PE
- Wound (POD 5–7): surgical site infection
- Wonder drugs / "What did we do" (POD 7+): drug fever, IV/central-line infection, deep abscess, anastomotic leak
Accuracy note: atelectasis is the classic POD 1–2 answer, but evidence that it directly causes fever is weak — early fever more often reflects the normal inflammatory (cytokine) response to surgery, with pneumonia the leading true infectious cause. Immediate fever (within hours): think malignant hyperthermia, transfusion reaction, a pre-existing infection, or an early necrotizing wound infection (group A Strep / Clostridium).
Post-op fever timeline
| POD | "W" | Leading cause | First step |
|---|---|---|---|
| 0 (hrs) | — | Malignant hyperthermia, transfusion rxn, necrotizing infection | Dantrolene / stop transfusion / OR |
| 1–2 | Wind | Atelectasis, pneumonia | Incentive spirometry, ambulate; CXR |
| 3–5 | Water | UTI | Urinalysis + culture; remove Foley |
| 4–6 | Walking | DVT / PE | Lower-extremity duplex; CT-PA if PE suspected |
| 5–7 | Wound | Surgical site infection | Inspect wound; open/drain + antibiotics |
| 7+ | Wonder drugs | Drug fever, abscess, anastomotic leak, line infection | CT for abscess; stop offending drug; cultures |
Practice Surgery now
Board-style questions, spaced-repetition flashcards, and a Socratic AI tutor — free to start.