Mortality Is Lower Among ALI Patients Cared for in Closed ICU

Key Point

In the ICU, a closed model of care is associated with a 32% reduction in ICU mortality when compared with an open model.

In a study corroborating recommendations by the Society of Critical Care Medicine for a closed rather than an open model for delivering care in the ICU, Miriam Treggiari, MD, and colleagues have shown that the use of a closed model reduces the ICU mortality of patients with acute lung injury (ALI) by 32%. A closed model is one in which care is handled by a multidisciplinary team led by a full-time critical care physician who can be rapidly available in the ICU 24 hours a day.

“Although the mechanisms by which closed ICUs might reduce mortality are complex, these ICUs were different with regard to intensity of staffing, as indicated by greater presence of critical care physicians in the ICU, higher number of residents, and high nurse-to-patient ratio,” explained the authors. Lead author Dr. Treggiari is Director of Critical Care Research from the Department of Anesthesiology at the University of Washington School of Medicine in Seattle.

MULTIDISCIPLANARY TEAM

In the current study, ICU outcomes for patients with ALI treated in 24 ICUs in King County, Washington, were compared during a one-year period; 13 of the ICUs were closed and 11 were open.

Whereas an intensive care team directed patient care or the admitting physician had to consult and share responsibility with a board-certified critical care specialist in closed ICUs, “open ICUs were defined as units where any attending physician with ICU admitting privileges can be the physician of record and direct ICU care,” the authors said.

Data for the study were obtained via survey from 23 medical directors and 22 nurse managers working in the 24 participating ICUs. Complete data were available on 23 of the ICUs, which had a median size of 258 beds (range, 38 to 639 beds).

“Depending on the ICU, the team working in closed units included pulmonologists, internists, anesthesiologists, and surgeons, whereas comanaging physicians were pulmonologists and cardiologists,” Dr. Treggiari and colleagues related.

INCREASED AVAILABILITY TO PATIENTS

The average amount of daily coverage by a board-certified critical care specialist on weekdays and weekends was 8.9 and 6.9 hours, respectively, for closed units versus 5.5 and 5.1 hours, respectively, for open units. Physicians were more likely in closed units than in open units to be available by phone or present within five minutes, but this difference did not reach significance.

The nurse-to-patient ratio was higher during the day and night in the closed units (1:1.75 at both times) than in the open units (1:2 at both times). However, all ICUs except for one open unit reported the ability to increase the ratio to 1:1 if necessary.
Of the 1,075 patients with ALI in the study, 684 were in a closed ICU and 391 were in an open ICU.

Seventy-seven percent of the former group were seen by a pulmonary consultant, compared to 68% of the patients cared for in an open ICU.
Although the two groups were no different in terms of duration of mechanical ventilation or ICU length of stay, the patients in the closed ICUs were significantly more likely to survive (adjusted odds ratio for mortality, 0.68).

“This effect was independent of, and was not confounded by, whether a patient ever received consultation by a pulmonologist, suggesting that optional pulmonary consultation cannot substitute for a change in ICU organization,” said the authors.

“These data provide additional support for the effect of a closed-model ICU on the outcome of a common critical illness syndrome in a well-described population-based cohort.”           

—Timothy Begany

Suggested Reading
Treggiari MM, Martin DP, Yanez ND, et al. Effect of intensive care unit organizational model and structure on outcomes in patients with acute lung injury. Am J Respir Crit Care Med. 2007;176:685-690.

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