Ultrashort courses of antibiotics led to similar outcomes as longer durations of therapy among adults with suspected ventilator-associated pneumonia but minimal and stable ventilator settings, according to a large retrospective observational study.
The duration of antibiotic therapy did not significantly affect the time to extubation alive (hazard ratio, 1.2; 95% CI, 1.0-1.4), time to hospital discharge (HR, 1.1; 95% CI, 0.9-1.3), rates of ventilator death (HR, 0.8; 95% CI, 0.6-1.2), or rates of hospital death (HR, 1.0; 95% CI, 0.8-1.31).), said Michael Klompas, MD, and his associates at Harvard Medical School in Boston. If confirmed, the findings would support surveillance of serial ventilator settings to “identify candidates for early antibiotic discontinuation,” the investigators reported (Clin Infect Dis. 2016 Dec 29.).
Suspected respiratory infections account for up to 70% of ICU antibiotic prescriptions, a “substantial fraction” of which may be unnecessary, the researchers said. “The predilection to overprescribe antibiotics for patients with possible ventilator-associated pneumonia (VAP) is not due to poor clinical skills per se, but rather the tension between practice guidelines that encourage early and aggressive prescribing [and] the difficulty [of] accurately diagnosing VAP,” they wrote. While withholding antibiotics in suspected VAP is “unrealistic” and can contribute to mortality, observing clinical trajectories and stopping antibiotics early when appropriate “may be more promising,” they added.
To test that idea, the researchers studied 1,290 cases of suspected VAP treated at Brigham and Women’s Hospital between 2006 and 2014. On the day antibiotics were started and during each of the next 2 days, all patients had a daily minimum positive end-expiratory pressure (PEEP) of no more than 5 cm H2O and a daily minimum fraction of inspired oxygen (FiO2) of no more than 40%.
A total of 259 patients received 1-3 days of antibiotics, while 1,031 patients received more than 3 days of therapy. These two groups were similar demographically, clinically, and in terms of comorbidities. Point estimates tended to favor ultrashort course antibiotics, but no association reached statistical significance in the overall analysis or in subgroups based on confirmed VAP diagnosis, confirmed pathogenic infection, or propensity-matched pairs.
The results suggest “that patients with suspected VAP but minimal and stable ventilator settings can be adequately managed with very short courses of antibiotics,” Dr. Klompas and his associates concluded. “If these findings are confirmed, assessing ventilator settings may prove to be a simple and objective strategy to identify potential candidates for early antibiotic discontinuation.”
The work was supported by the Centers for Disease Control and Prevention’s Prevention Epicenters Program. The investigators had no relevant financial disclosures.