SCCM: Chlorhexidine Reduces Risk of Ventilator-Associated Pneumonia

ORLANDO, Feb. 19 -- Swabbing the oral cavity with chlorhexidine (Peridex) reduces the risk of ventilator-associated pneumonia in some intubated intensive care patients, a Virginia researcher said here.

Careful toothbrushing, on the other hand, had no effect, according to Cindy Munro, R.N., Ph.D., of Virginia Commonwealth University in Richmond.

Ventilator-associated pneumonia "is the most frequent nosocomial infection in the ICU," Dr. Munro reported at the Critical Care Congress of the Society for Critical Care Medicine here. It increases ICU mortality, length of stay and cost, she added.

For that reason, she and colleagues initiated a randomized, controlled trial at the university's school of nursing, in which intubated ICU patients were assigned to one of four treatments -- usual care, toothbrushing three times daily, chlorhexidine twice daily, or toothbrushing and chlorhexidine combined.

Assessment of ventilator-associated pneumonia was made using the Clinical Pulmonary Infection Score, a 12-point scale based on such variables as white blood count, temperature, and tracheal aspirate bacteria.

A Clinical Pulmonary Infection Score of six or greater is indicative of ventilator-associated pneumonia, Dr. Munro said. In the study, clinicians assessing ventilator-associated pneumonia in a given patient were blinded as to the intervention being used, she said.

The Clinical Pulmonary Infection Score was measured at day one of intubation, and again at days three, five, and seven, while patients continued in the study until day seven or until the tube was removed, whichever came first.

All told, 249 patients in the study remained intubated until day three, Dr. Munro said, and complete day three data was analyzed for 192 of them.

The study found that overall there was no significant effect of either intervention at day three.

But among patients whose Clinical Pulmonary Infection Score was less than six at day one, chlorhexidine led to a significantly lower Clinical Pulmonary Infection Score at day three than did toothbrushing (4.36 versus 5.36, which was significant at P=0.0174).

More importantly, Dr, Munro said, in that healthier group of patients, chlorhexidine also significantly reduced the risk of ventilator-associated pneumonia compared with toothbrushing -- 24.4% of chlorhexidine-treated patients got ventilator-associated pneumonia, compared with 52.4% of others, which was significant at P=0.0093.

While Dr. Munro only reported data for patients who remained intubated for three days, she said "the trends are the same" for the smaller number of patients who remained on a ventilator for five and seven days.

"The study shows that the most severely compromised were least likely to benefit from the intervention," she said.

The finding is similar to what is seen in other interventions aimed at reduced ventilator-associated pneumonia, Dr. Munro said later. For instance, raising the head of the bed is known to lower the risk of ventilator-associated pneumonia, but the effect is more significant in healthier patients.

Chlorhexidine is usually used in the dental setting, she said, but it is recommended as a topical anti-microbial in elective cardiac surgery patients needing intubation, where it has been shown to reduce ventilator-associated pneumonia.

The bottom line of this study, she said is that "in addition to cardiac surgery patients, it also is helpful in treating other intubated patients." Whether the study should change clinical practice remains an open question, she said: "I hate to suggest anybody should change practice based on a single study."