Critical Care Medicine
Critical care questions reward a systematic approach to shock, respiratory failure, and sepsis. Distinguish the four shock states (hypovolemic, cardiogenic, distributive, obstructive) by physical exam, lactate, and bedside ultrasound findings. Know the Surviving Sepsis principles: early balanced crystalloid resuscitation, lactate-guided reassessment, early broad-spectrum antibiotics with source control, and norepinephrine as the first-line vasopressor. Understand the difference between ARDS (bilateral opacities, PaO2/FiO2 ≤300, not primarily cardiogenic) and cardiogenic pulmonary edema, and the lung-protective ventilation targets (6 mL/kg predicted body weight, plateau pressure <30 cmH2O).
Traps
Questions test your ability to avoid the wrong reflex. Do not give a fluid bolus to a patient with obvious cardiogenic shock or a large PE - you will worsen right-heart failure. Recognize permissive hypercapnia as acceptable in ARDS. Know that a normal lactate does not exclude shock and that a high lactate can occur without hypoperfusion (seizures, liver failure, metformin). Watch for the patient with a rising oxygen requirement and a normal chest radiograph - consider PE, shunt, or early ARDS.
Worked example
A patient with septic shock on norepinephrine has a MAP of 58 despite 30 mL/kg crystalloid. The next step is not more fluid blindly; reassess volume responsiveness (passive leg raise, stroke volume variation) and consider adding vasopressin or epinephrine, plus source control.