Prophylactic Antimicrobial Therapy for Acute Aspiration Pneumonitis.

Background: Prophylactic antimicrobial therapy is frequently prescribed for acute aspiration pneumonitis, with the intent of preventing the development of aspiration pneumonia. However, few clinical studies have examined the benefits and harms of this practice.

Methods: A retrospective cohort study design was used to compare outcomes of patients with aspiration pneumonitis who received prophylactic antimicrobial therapy with those managed with supportive care only during the initial 2 days following macroaspiration. The primary outcome was in-hospital mortality within 30 days. Secondary outcomes included transfer to critical care and antimicrobial therapy received between days 3 and 14 following macroaspiration including escalation of therapy and antibiotic-free days.

Results: Among 1483 patients reviewed, 200 met the case definition for acute aspiration pneumonitis, including 76 (38%) who received prophylactic antimicrobial therapy and 124 (62%) who received supportive management only. After adjusting for patient-level predictors, antimicrobial prophylaxis was not associated with any improvement in mortality (odds ratio, 0.9; 95% confidence interval [CI], 0.4-1.7; P = .7). Patients receiving prophylactic antimicrobial therapy were no less likely to require transfer to critical care (5% vs 6%; P = .7) and subsequently received more frequent escalation of antibiotic therapy (8% vs 1%; P = .002) and fewer antibiotic-free days (7.5 vs 10.9; P < .0001).

Conclusions: Prophylactic antimicrobial therapy for patients with acute aspiration pneumonitis does not offer clinical benefit and may generate antibiotic selective pressures that results in the need for escalation of antibiotic therapy among those who develop aspiration pneumonia.