Ventilator-associated pneumonia — FFICM MCQ

Correct answer: C — Start empirical broad-spectrum antibiotics then review cultures

The correct answer is C, start empirical broad-spectrum antibiotics then review cultures. This patient has clinical, radiological and physiological features of ventilator-associated pneumonia (fever, purulent secretions, new infiltrate, worsening oxygenation, vasopressor requirement), and NICE guidance on hospital-acquired pneumonia states that samples for culture should be taken but antibiotic treatment should not be delayed while awaiting the result. Given his haemodynamic instability on noradrenaline, any delay risks progression to septic shock and worse outcome, so broad-spectrum cover targeting likely pathogens (including Pseudomonas and other Gram-negatives) is started immediately after sampling, then rationalised once microbiology and clinical response are known. This reflects the standard sepsis and VAP management principle of sample-then-treat, followed by de-escalation. Why the other options are wrong: A, withhold antibiotics until quantitative culture is available: this delays treatment in a physiologically unstable, deteriorating patient and is contrary to guidance that treatment should start promptly once infection is suspected, not after culture confirmation. C, start nebulised colistin as sole treatment: nebulised colistin alone does not achieve adequate systemic or tissue levels for a patient with signs of systemic sepsis and haemodynamic compromise, and is used only as adjunctive therapy for resistant Gram-negative organisms, not monotherapy for suspected VAP. D, change the ventilator circuit and observe: circuit change does not address established pulmonary infection with systemic features and simply observing risks clinical deterioration. E, treat with oral doxycycline via nasogastric tube: doxycycline lacks reliable activity against the Gram-negative and Pseudomonal organisms typically implicated in late-onset VAP and is not appropriate first-line broad-spectrum empirical therapy in a septic, vasopressor-dependent ICU patient. Key point: in suspected VAP with haemodynamic instability, take respiratory samples but start empirical broad-spectrum antibiotics immediately, then de-escalate according to culture results and clinical response.

Reference: NICE guideline NG250, Pneumonia: diagnosis and management (hospital-acquired pneumonia antimicrobial prescribing), September 2025, https://www.nice.org.uk/guidance/ng250