ABIM Critical Care cheat sheet

ARDS Berlin criteria: acute onset within 1 week, bilateral opacities, PaO2/FiO2 ≤300 with PEEP ≥5 cmH2O, not primarily cardiogenic.

Lung-protective ventilation: tidal volume 6 mL/kg predicted body weight, plateau pressure ≤30 cmH2O, permissive hypercapnia.

Auto-PEEP: end-expiratory flow not returning to zero; manage by reducing respiratory rate, increasing expiratory time, treating obstruction.

Respiratory compliance = tidal volume / (plateau pressure − total PEEP); normal 50-70 mL/cmH2O.

Airway resistance = (peak pressure − plateau pressure) / flow; normal ≤10 cmH2O/L/s.

Prone positioning for ARDS with PaO2/FiO2 <150 improves mortality when applied ≥16 hours/day.

Weaning criteria: rapid shallow breathing index (RSBI) = respiratory rate / tidal volume (L) <105 predicts extubation success.

COPD exacerbation: controlled oxygen to SpO2 88-92%, bronchodilators, systemic steroids, antibiotics if increased sputum purulence.

Pulmonary embolism: Wells score, D-dimer for low/intermediate probability, CT angiography for high probability or positive D-dimer; massive PE with hypotension requires thrombolysis or embolectomy.

Cardiogenic shock: SBP <90 mmHg or vasopressors required, cardiac index <2.2 L/min/m2, PCWP >15 mmHg, signs of hypoperfusion.

Septic shock: vasopressors to maintain MAP ≥65 mmHg, lactate >2 mmol/L despite fluid resuscitation.

ScvO2 <70% suggests inadequate oxygen delivery; >80% suggests impaired oxygen utilization (e.g., sepsis).

Pulse pressure variation >13% or systolic pressure variation >10% predicts fluid responsiveness in mechanically ventilated patients.

Norepinephrine is first-line vasopressor for septic shock; add vasopressin 0.03 units/min or epinephrine to reach MAP goal.

STEMI: door-to-balloon <90 minutes; fibrinolysis within 30 minutes if PCI not available and symptom onset <12 hours.

Atrial fibrillation with rapid ventricular response and hemodynamic instability: immediate synchronized cardioversion.

Aortic dissection: avoid beta-blockade before blood pressure control? Actually, first-line IV beta-blocker (e.g., esmolol) to reduce dP/dt, then add vasodilator if needed.

Glasgow Coma Scale: eye (1-4), verbal (1-5), motor (1-6); score ≤8 indicates severe coma and need for airway protection.

Elevated ICP: head of bed 30°, avoid neck compression, maintain normocapnia (PaCO2 35-40 mmHg), hypertonic saline or mannitol for acute herniation.

Cerebral perfusion pressure (CPP) = MAP − ICP; target CPP 60-70 mmHg in traumatic brain injury.

Status epilepticus: benzodiazepines first-line; if persistent, fosphenytoin, valproate, or levetiracetam; refractory requires continuous infusion midazolam or propofol.

Subarachnoid hemorrhage: nimodipine 60 mg every 4 hours for 21 days to prevent delayed cerebral ischemia.

Ischemic stroke: IV alteplase within 3-4.5 hours of onset if no contraindications; thrombectomy for large vessel occlusion up to 24 hours in selected patients.

Brain death: absence of brainstem reflexes, apnea test with PaCO2 >60 mmHg and no respiratory effort, and no confounding factors.

Acute kidney injury (KDIGO): increase in serum creatinine ≥0.3 mg/dL within 48 hours or ≥1.5 times baseline within 7 days, or urine output <0.5 mL/kg/h for 6 hours.

Fractional excretion of sodium (FENa) = (urine Na × plasma Cr) / (plasma Na × urine Cr) × 100; <1% suggests prerenal, >2% intrinsic.

Hyperkalemia with ECG changes: IV calcium gluconate, insulin with glucose, beta-agonists, sodium bicarbonate if acidemic, then dialysis or potassium binders.

Hyponatremia: correct ≤8-10 mmol/L in 24 hours to avoid osmotic demyelination; use hypertonic saline for severe symptoms.

Anion gap = Na − (Cl + HCO3); normal 8-12 mmol/L; elevated in lactic acidosis, ketoacidosis, renal failure, toxins.

Winter's formula: expected PaCO2 = 1.5 × HCO3 + 8 ± 2; if actual PaCO2 differs, mixed disorder.

Osmolal gap = measured osmolality − calculated (2Na + glucose/18 + BUN/2.8); >10 suggests toxic alcohol ingestion.

Renal replacement therapy indications: refractory acidosis, electrolyte imbalance, intoxication, overload, uremia (AEIOU).

Sepsis-3: life-threatening organ dysfunction due to dysregulated host response to infection; organ dysfunction defined as increase in SOFA score ≥2.

Septic shock: sepsis with vasopressor requirement to maintain MAP ≥65 mmHg and lactate >2 mmol/L despite adequate fluid resuscitation.

Early goal-directed therapy: within 3 hours, measure lactate, obtain blood cultures before antibiotics, administer broad-spectrum antibiotics, and 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L.

Antibiotic de-escalation based on culture results and clinical improvement reduces resistance and cost.

Ventilator-associated pneumonia: occurs >48 hours after intubation; common organisms include Pseudomonas, MRSA, and gram-negative bacilli.

Catheter-related bloodstream infection: remove catheter if S. aureus, Pseudomonas, or Candida; otherwise salvage may be considered.

Clostridioides difficile: oral vancomycin or fidaxomicin first-line; avoid antiperistaltics.

Diabetic ketoacidosis: glucose >250 mg/dL, pH <7.3, bicarbonate <18, anion gap >10, ketonemia; treat with IV fluids, insulin infusion, and potassium replacement.

Hyperosmolar hyperglycemic state: glucose >600 mg/dL, effective osmolality >320 mOsm/kg, minimal ketosis; high mortality.

Thyroid storm: fever, tachycardia, altered mental status; treat with beta-blocker, thionamide, iodine (after thionamide), and glucocorticoids.

Adrenal crisis: hypotension unresponsive to fluids, hyponatremia, hyperkalemia; treat with IV hydrocortisone 100 mg then 50 mg every 6 hours.

Refeeding syndrome: hypophosphatemia, hypokalemia, hypomagnesemia after reintroduction of nutrition; start feeding at low calories and monitor electrolytes.

Nutrition in critical illness: early enteral nutrition within 24-48 hours if hemodynamically stable; parenteral nutrition if enteral contraindicated.

Myxedema coma: hypothermia, bradycardia, altered mentation; treat with IV levothyroxine and stress-dose hydrocortisone until adrenal insufficiency excluded.

Upper GI bleed: IV proton pump inhibitor after endoscopic hemostasis; variceal bleed: octreotide and prophylactic antibiotics.

Acute liver failure: coagulopathy (INR ≥1.5) and encephalopathy in patient without cirrhosis; consider N-acetylcysteine for acetaminophen toxicity.

Hepatic encephalopathy: lactulose titrated to 2-3 bowel movements per day; rifaximin for secondary prophylaxis.

Spontaneous bacterial peritonitis: ascitic fluid PMN ≥250/mm3; treat with third-generation cephalosporin and albumin 1.5 g/kg on day 1 and 1 g/kg on day 3.

Heparin-induced thrombocytopenia: platelet drop >50% or thrombosis; stop heparin, start argatroban or bivalirudin.

Disseminated intravascular coagulation: prolonged PT/PTT, low fibrinogen, elevated D-dimer, thrombocytopenia; treat underlying cause and replace factors if bleeding.

Transfusion thresholds: restrictive strategy (hemoglobin <7 g/dL) for most critically ill patients; <8 g/dL for active cardiovascular disease.

Advanced trauma life support primary survey: airway, breathing, circulation, disability, exposure.

Hemorrhagic shock: class I <15% blood loss, class II 15-30%, class III 30-40%, class IV >40%; base deficit and lactate guide resuscitation.

Massive transfusion protocol: 1:1:1 ratio of packed RBCs, plasma, and platelets; limit crystalloids.

Burns: Parkland formula for fluid resuscitation: 4 mL/kg/% total body surface area in 24 hours, half in first 8 hours.

Burn escharotomy for circumferential full-thickness burns with compromised perfusion.

Abdominal compartment syndrome: intra-abdominal pressure >20 mmHg with new organ dysfunction; decompressive laparotomy.

Damage control surgery: control hemorrhage and contamination, temporary closure, then definitive repair after physiologic stabilization.

Acetaminophen toxicity: N-acetylcysteine within 8-10 hours of ingestion; use Rumack-Matthew nomogram for treatment threshold.

Salicylate toxicity: alkaline diuresis with sodium bicarbonate, hemodialysis for severe toxicity.

Toxic alcohols (methanol, ethylene glycol): fomepizole or ethanol, hemodialysis for severe acidosis or visual symptoms.

Organophosphate poisoning: atropine for muscarinic symptoms, pralidoxime for nicotinic effects.

Carbon monoxide poisoning: 100% oxygen; hyperbaric oxygen for severe poisoning (loss of consciousness, neurologic signs, cardiac ischemia).

Beta-blocker overdose: glucagon, high-dose insulin with glucose, calcium, vasopressors; pacing for bradycardia.

Serotonin syndrome: stop serotonergic agents, supportive care, benzodiazepines, cyproheptadine for severe cases.

Central venous catheter: ultrasound guidance reduces complications; confirm tip position with chest X-ray.

Arterial line: complications include thrombosis, infection, and hematoma; avoid in inadequate collateral circulation.

Endotracheal intubation: preoxygenation, rapid sequence intubation with sedative and neuromuscular blocker; confirm with capnography.

Cardiopulmonary resuscitation: chest compressions at 100-120/min, depth 5-6 cm, minimize interruptions, early defibrillation for shockable rhythms.

Post-cardiac arrest care: targeted temperature management (32-36°C) for comatose survivors, maintain normoxia and normocapnia.

Pulmonary artery catheter: provides cardiac output, PCWP, and mixed venous oxygen saturation; use judiciously due to risk.

Thoracentesis: ultrasound guidance, avoid if coagulopathy; complications include pneumothorax and bleeding.

Informed consent: patient must have decision-making capacity, be informed of risks/benefits/alternatives, and consent voluntarily.

Surrogate decision-making: follow patient's advance directive or substituted judgment; if unknown, best interests standard.

Futility: interventions that cannot achieve the intended physiologic goal; may be withheld or withdrawn with appropriate process.

Palliative care: multidisciplinary approach to relieve suffering; can be provided alongside curative treatment.

Withdrawal of life-sustaining therapy: ensure symptom management (opioids, benzodiazepines) and family support; ethical and legal.

Brain death determination: irreversible loss of all brain function; follow institutional protocol and confirm with apnea test.

Confidentiality: may be breached to prevent serious harm (e.g., impaired driving, communicable disease) per legal requirements.

Central line-associated bloodstream infection (CLABSI) prevention bundle: hand hygiene, maximal sterile barrier, chlorhexidine skin antisepsis, optimal site selection, daily review of line necessity.

Ventilator-associated pneumonia (VAP) prevention: head of bed elevation 30-45°, daily sedation interruption, oral care with chlorhexidine, peptic ulcer prophylaxis.

Catheter-associated urinary tract infection (CAUTI) prevention: avoid unnecessary catheters, use aseptic insertion, maintain closed drainage, remove early.

Medication reconciliation at transitions of care reduces adverse drug events.

Root cause analysis: structured method to identify underlying causes of adverse events and prevent recurrence.

Handoff communication: use standardized tools (e.g., SBAR) to ensure transfer of critical information.

Quality metrics: structure, process, and outcome measures; e.g., mortality, length of stay, readmission rates.