Insult to Injury: How a Common Practice to Prevent Pneumonia in Patients on Ventilation May Not Be Helping


Patients who are on life support with mechanical ventilation after an accident or surgery are already in a precarious position, but as many as a quarter of all ventilated patients can develop ventilator-associated pneumonia (VAP). This sub-type of traditional pneumonia can double the risk of death, and increases the length of hospitalization and costs of care.

To combat ventilator-associated pneumonia, current guidelines recommend twice-daily use of an antiseptic called chlorhexidine gluconate (CHG) in all patients who are on a mechanical ventilator. This amounts to millions of patients, and tens of millions of patient-days, every year. Yet a new study published in JAMA Internal Medicine this week shows that–outside of patients undergoing cardiac surgery–CHG has no benefit for objective patient outcomes, such as length of hospitalization or time spent on ventilation.

Why was CHG recommended in the first place? Previous studies showed that CHG lowered the rates of VAP, but these studies lumped together cardiac surgery patients, who are typically taken off mechanical ventilation after a short period of time, and ICU patients who may be intubated much longer. Results vary widely across these different patient populations.

Michael Howell, Associate Chief Medical Officer for Clinical Quality at the University of Chicago Medicine and one of the co-authors on the study, said there’s another small problem with these recommendations too.

Michael Howell, MD, MPH

“It turns out that ‘pneumonia’ is really hard to define in patients on ventilators,” he said.

In a separate study also published this month, Howell and his colleagues showed that if they gave standardized cases to 43 hospitals, they came back with a pneumonia rate ranging anywhere from zero to 100 percent. These problems with being able to define pneumonia in ventilated patients, Howell said, actually led the CDC to get rid of its ventilator-associated pneumonia definition recently.

The latest study, which also included researchers from Harvard, Brigham and Women’s Hospital, Johns Hopkins and Rochester Medical Center, looked at whether CHG improved more objective outcomes in ICU patients, including length of hospitalization, time spent in the ICU and duration of ventilation, rather than looking just at pneumonia. They found that there was no benefit (and that there may have been a trend toward harm), particularly in patients other than cardiac surgery patients.

“While our findings are not conclusive,” the authors wrote, “they are sufficiently concerning to prompt a reevaluation of policies and initiatives that encourage or compel hospitals to include chlorhexidine in routine oral care for non–cardiac surgery patients.”

Klompas M., Speck K., Howell M.D., Greene L.R. & Berenholtz S.M. Reappraisal of Routine Oral Care With Chlorhexidine Gluconate for Patients Receiving Mechanical Ventilation, JAMA Internal Medicine, DOI:

About Matt Wood (531 Articles)
Matt Wood is a senior science writer and manager of communications at the University of Chicago Medicine & Biological Sciences Division.
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