UF researchers say viruses could play key role in ICU patients’ outcomes

Common viral infections appear to play a role in why some critically ill patients struggle to recover, according to University of Florida researchers who studied how influenza and other infectious agents affect the health outcomes of patients in intensive care units.

“It’s reasonable to assume that when a critically ill patient also has a viral infection, it can adversely affect their clinical outcome,” said Darwin Ang, M.D., Ph.D., M.P.H., a UF assistant professor of surgery in the College of Medicine and senior author of the paper. “These patients are trying to recover from a physiologic insult that brought them to the intensive care unit, and a newly acquired viral infection may prevent their recovery.”

Although it seems reasonable that infections can hinder the recovery of critically ill patients, scant evidence exists to justify more aggressive screening and treatment strategies. Patients in intensive care are not normally tested for viral infections throughout their hospital stay.

Now, in the first study to look at more than one virus across a widespread sample population, UF researchers analyzed the role infections played in the health outcomes of more than 200,000 critically ill patients across the United States using data from the national University HealthSystem Consortium. The results were published online in the journal PLoS ONE.

Looking at patients who appeared to be infection-free when they were admitted to the hospital, investigators focused on four common, treatable viral infections — influenza, cytomegalovirus, herpes simplex virus, and respiratory syncytial virus — and their role in hospital complications such as death, septic shock, multi-organ failure, diarrhea and pneumonia.

The average stay of patients who were apparently free of infection was 11.5 days, compared with 21 days for those infected with viruses and 46.2 days for patients who had both viral and bacterial infections. Patients with both bacterial and viral infections had the strongest association with poorer outcomes such as death, multi-organ failure and septic shock.

“If we know that these viruses exist, we can’t ignore their potential impact on patients,” said Makesha Miggins, M.D., a UF surgical resident and lead author on the paper. “We are trying to present a new approach, if not change the whole process, of how we treat and evaluate intensive care unit patients.”

Researchers also analyzed risk of infection by season, finding an “upstroke” as winter months approached. They add that viruses may be lying dormant in some patients and may reactivate as their bodies fight to recover from critical injuries or illnesses.

The study deals with a poorly understood component of recovery in critically ill patients.

“The impact of secondary viral infections and/or reactivation may be critical to the survival of these tenuous patients and to date has been little studied and the true incidence and impact unknown,” said Ronald V. Maier, M.D., a professor and vice chair of surgery at the University of Washington who was not involved in the research.

The idea to study the role of viral infections came from Ang’s rounds in the ICU, where he noticed patients with fevers who remained ill, yet had negative results for bacterial infections and other routine tests administered.

Researchers say the findings give cause for additional study of the prevalence of viruses in critically ill patients, particularly during the winter and fall months. They may learn that antiviral medications may improve outcomes.

While he does not recommend making medical practice changes without further study, Ang said, “The results of this study will likely influence my practice by testing for viral infections in critically ill patients who have no other conventional explanation for their clinical deterioration.” He added that he would pay special attention to these infections during winter and fall and the flu season.

According to a 2007 article in the Journal of the American Medical Association, about one-fifth of all Americans will be a patient in the ICU during their lifetime.