Antibiotics Decrease Mortality in Ventilator-Associated Tracheobronchitis

Emma Hitt, PhD

February 05, 2008

February 5, 2008 (Honolulu) — Antibiotic treatment significantly reduces rates of pneumonia infection and subsequent mortality in patients with ventilator-associated tracheobronchitis (VAT), according to an interim analysis of the first prospective randomized multicenter study to examine this issue, presented here at the Society of Critical Care Medicine 37th Critical Care Congress.

"We expected that the duration of mechanical ventilation but not mortality would decrease with treatment of VAT," noted the lead author, Saad Nseir, MD, from the Centre Hospitalier Régional Universitaire, Lille, France. "However, this result is logical since subsequent ventilator-associated pneumonia rate was also significantly different between the 2 groups," he told Medscape Critical Care.

A total of 44 patients with a first episode of VAT diagnosed at least 48 hours after starting mechanical ventilation were randomly assigned to receive either intravenous antibiotics (n = 22) for 8 days or no antibiotics (n = 36). VAT was identified by the presence of a purulent tracheal aspirate, a fever of at least 38°C with no other recognizable cause, a positive tracheal aspirate culture with more than 1 × 106 colony-forming units/mL, and the absence of new infiltrate on chest radiograph.

Patient characteristics were similar between the groups. The most common infection was with Pseudomonas aeruginosa, which was present in 36% of the patients. Other causative organisms included Staphylococcus aureus and Escherichia coli.

Subsequent ventilator-associated pneumonia infections decreased significantly in the group receiving antibiotics compared with the control group (3% vs 17%; P = .011). Likewise, intensive care unit mortality rates decreased with antibiotic treatment (4% vs 17%; P = .047).

The duration of mechanical ventilation was not significantly different between groups (29 days with antibiotics vs 26 days without), although more ventilation-free days were observed in the group receiving treatment (12 vs 2 days; P < .001). Because of the significant differences in mortality between the groups, the study was terminated for ethical reasons after the first interim analysis.

According to Dr. Nseir, remaining questions include the optimal duration of antibiotic use and whether aerosolized antibiotics might be useful in this setting.

Stephen M. Pastores, MD, from the Memorial Sloan-Kettering Cancer Center, New York City, who moderated the session, noted that this is a first-of-a-kind prospective study and has important clinical implications. "Since VAT can lead to pneumonia and mortality, these study results suggest that more attention should be given to screening for VAT — which I think makes sense. These researchers reported a prevalence of 3% to 10%, so VAT may be more common than we like to think."

However, he added that "it is very difficult to determine the exact incidence and importance of VAT, as the definition of VAT has not been validated and the use of 'new or increased sputum production' and 'absence of infiltrates on a chest radiograph' are rather imprecise." One question that arises with the study is whether patients with VAT were truly negative for ventilator-associated pneumonia at baseline, he told Medscape Critical Care. "If some patients were positive for pneumonia and received appropriate antimicrobial treatment, this may have been the reason for the decreased mortality rates."

According to Dr. Pastores, additional studies are needed with more precise and objective criteria for the diagnosis of VAT to determine the real effect of antibiotic treatment on outcome in these patients.

The funding for this study was provided by the University Hospital of Lille, France. Dr. Nseir and Dr. Pastores have disclosed no relevant financial relationships.

Society of Critical Care Medicine 37th Critical Care Congress: Abstract 62. Presented February 3, 2008.


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