SAN DIEGO – Decreased availability of medical ICU beds was significantly associated with a 27% higher risk for cardiac arrest on general hospital wards in an observational cohort study of 68 ICU beds and 258 ward beds at one academic medical center.
The availability of nonmedical ICU beds did not affect the risk of cardiac arrests. While total ICU bed availability was associated with increased cardiac arrests, this did not reach statistical significance, Michael Huber and his associates reported at the annual meeting of the Society of Hospital Medicine.
Michael Huber
Across the United States, the approximately 90,000 ICU beds account for less than 15% of all hospital beds and are distributed unevenly geographically. Demand for ICU beds is projected to increase 80% over the next 209 years as the population ages and comorbidities increase, said Mr. Huber, a fourth-year medical student at the University of Chicago.
The findings suggest a need to increase ICU bed availability by adding beds, adopting flexible surgery scheduling for planned surgical ICU admissions (which in turn may open up ICU beds for medical patients), or implementing practices to reduce ICU length of stay, he suggested. "Of course, some ICU beds are taken by patients awaiting discharge to wards, so prioritizing ward beds to ICU discharges may also free up ICU beds."
A second implication of the study is that ward patients may be triaged inappropriately when ICU beds are severely limited, he added. Improved ICU triage practices may be needed, particularly at times of limited medical ICU bed availability.
The study was honored as one of the best research presentations at the meeting. It defined cardiac arrest as loss of a palpable pulse with a resuscitation attempt.
Researchers analyzed 96 cardiac arrests on the general wards (81 arrests on medical wards and 15 on non-medical wards). During 1,716 work shifts, there were a median of 217 patients on the wards at the start of 12-hour shifts. A median of five total ICU beds were available at shift start. For medical ICU beds, a median of one was available at shift start, and for nonmedical ICU beds, a median of three were available at shift start.
The incidence rate of cardiac arrests on the general wards was 6% higher for each fewer ICU bed, but this was not a statistically significant difference. For each fewer medical ICU bed, a 27% increase in cardiac arrests on the general wards was seen, which was significant. No association appeared between non-medical ICU bed availability and cardiac arrests on the wards.
The investigators calculated a "ward cardiac arrest rate" (defined as the number of ward cardiac arrests divided by ward occupancy at shift start) and compared these by the number of ICU beds available. The mean cardiac arrest rate was 2.6 arrests per 10,000 ward patients per shift. The rate when no medical ICU beds were available was nearly double the rate when one or more medical ICU beds were available. The cardiac arrest rate stabilized at or below the mean when one, two, or three or more medical ICU beds were available, Mr. Huber said.
Previous studies focused mostly on the effects of bed availability on patients in the ICU. They found no association with mortality but showed increased severity of illness and readmission rates as ICU bed availability decreased. Previous studies of ward patients were limited to high-risk patients who were evaluated for ICU admission; these found higher mortality rates in patients who were refused admission to the ICU, he said.
Mr. Huber reported having no financial disclosures. One of his associates reported financial ties to Philips Healthcare and Sotera Wireless.