Critical Care and Intensive Care Medicine
ICU items test definitions, first-line management and ventilator arithmetic. Sepsis, ARDS, AKI, sedation and delirium are high-yield.
Sepsis and shock
- Sepsis-3: suspected infection plus SOFA of 2 or more; septic shock is vasopressor requirement for MAP 65 mmHg or above with lactate above 2 mmol/L despite fluids.
- Bundle: cultures, broad antibiotics within 1 hour, 30 mL/kg crystalloid, then norepinephrine; measure lactate.
- Balanced crystalloid is preferred; avoid starches.
ARDS and ventilation
- Berlin definition: onset within 1 week, bilateral opacities, not explained by cardiac failure, P/F ratio 300 or less on PEEP of at least 5.
- Tidal volume 6 mL/kg predicted body weight, plateau pressure under 30 cmH₂O, permissive hypercapnia unless intracranial pressure is raised.
- Predicted body weight: male = 50 + 0.91 × (height cm − 152.4); female = 45.5 + 0.91 × (height cm − 152.4).
Organ support
- AKI: KDIGO staging by creatinine and urine output; stop nephrotoxins, optimise perfusion.
- Sedation: target RASS −2 to −1 with propofol or dexmedetomidine; daily interruption; the ABCDEF bundle reduces delirium.
- Transfuse at Hb 7 g/dL; target glucose 8–10 mmol/L.
Worked example
A 170 cm man weighing 70 kg with ARDS. Predicted body weight = 50 + 0.91 × 17.6 ≈ 66 kg. Set tidal volume at 6 × 66 ≈ 400 mL, not 6 × 70 = 420 mL, and confirm plateau pressure below 30 cmH₂O. Using actual weight over-ventilates and is a classic exam error.
Traps
Dosing lung-protective ventilation by actual weight; giving fluid for every episode of oliguria; defaulting to deep sedation; diagnosing ARDS without applying PEEP.