Oral Antiseptics Curb Ventilator-Associated Pneumonia

UTRECHT, The Netherlands, June 15 - Oral swabbing with antiseptics may be an inexpensive and effective way to prevent bacterial pneumonia in patients on mechanical ventilators, according to a study here.

Eight days of such treatment cost only per patient and reduced ventilator-associated pneumonia by 55% to 65%, said Mirelle Koeman, M.D., of the University Medical Center Utrecht in the June issue of the American Journal of Respiratory and Critical Care Medicine.

In the U.S., ventilator-associated pneumonia is second only to urinary tract infections as the most common hospital-acquired infection, affecting about 27% of all critically ill patients and leading to increased morbidity and "high" mortality rates, Dr. Koeman and colleagues said. The ventilator breathing tube facilitates colonization of bacteria in the mouth in the airways and lungs, the researchers noted.

The double-blind study included 385 patients requiring mechanical ventilation for 48 hours or more at two university hospitals and three general hospitals in The Netherlands during 2001 to 2003. One third of the patients were randomized to oral swabs with a paste containing Peridex (chlorhexidine) every six hours, one third were randomized to a paste containing both Peridex and colistin (an antiseptic sold under a variety of brand names), and one third of patients received a placebo paste.

Ventilator-associated pneumonia occurred in 18% of the placebo group, 10% of the Peridex group, and 13% of the combination group.

Compared with the placebo group, the daily risk for pneumonia was reduced in both the Peridex group (hazard ratio=0.35; 95% confidence interval=0.16 to 0.79; P=.012) and the combination antiseptic group (HR=0.45; 95% CI=0.22 to 0.93; P=.03), the study found.

Culture tests taken at days five through eight showed that, compared with the placebo group, the proportion of patients whose airways had become colonized with bacteria was lower in the combination antiseptic group (16% versus 40% in the placebo group; P=.007).

Colonization rates were also lower in the combination group compared with the Peridex group (16% versus 38%; P=.011), largely because of reductions in colonization with gram-negative bacteria, the researchers said.

The study found no differences among the groups in time spent on ventilation, length of intensive care unit stay, or mortality rates. However, a chief limitation of the study was that it was not powered to detect effects on patient survival, the authors said.

"Because all patients with ventilator-associated pneumonia received appropriate treatment, attributable mortality in our population is probably low and much larger patient populations would be needed to determine differences in patient outcome," they said.

"Our findings confirm and expand these previous observations regarding the pivotal role of oropharyngeal colonization in the pathogenesis of ventilator-associated pneumonia and the potential of chlorhexidine, either alone or in combination with colistin, in preventing and postponing the development of ventilator-associated pneumonia," they concluded.

Oral antiseptics are a better option than prophylactic antibiotics because routine use of antiseptics would not contribute significantly to the problem of antibiotic resistance, the authors said.

The study's small sample size not only limited its power to detect patient outcomes, it increased the odds the results are in error, according to an editorial by Donald E. Craven, M.D., of the Lahey Clinic Medical Center in Burlington, Mass., and Robert A. Duncan, M.D., M.P.H., of Tufts in Boston.

"For example, there appear to be significantly more males and patients with infections in the placebo group, which questions the effectiveness of randomization," they said. "In addition, it is difficult to reconcile significant reductions in ventilator-associated pneumonia risk with an absence of effect on ventilator days, length of stay, or mortality."

They also pointed out that "in this study, ventilator-associated pneumonia rates appeared high, perhaps reflecting the inclusion of Candida species and their commensals that may represent colonization rather than ventilator-associated pneumonia.

"Nonetheless, this is an impressive result for an inexpensive, nontoxic modality and warrants further attention," they said.