A Randomized Trial of Nighttime Physician Staffing in an Intensive Care Unit

Study Questions:

What are the benefits of nighttime intensivist staffing?


The investigators conducted a 1-year randomized trial in an academic medical intensive care unit (ICU) of the effects of nighttime staffing with in-hospital intensivists (intervention) as compared with nighttime coverage by daytime intensivists who were available for consultation by telephone (control). They randomly assigned blocks of 7 consecutive nights to the intervention or the control strategy. The primary outcome was patients’ length of stay in the ICU. Secondary outcomes were patients’ length of stay in the hospital, ICU and in-hospital mortality, discharge disposition, and rates of readmission to the ICU. For length-of-stay outcomes, they performed time-to-event analyses, with data censored at the time of a patient’s death or transfer to another ICU.


A total of 1,598 patients were included in the analyses. The median APACHE III (Acute Physiology and Chronic Health Evaluation III) score (in which scores range from 0-299, with higher scores indicating more severe illness) was 67 (interquartile range, 47-91), the median length of stay in the ICU was 52.7 hours (interquartile range, 29.0-113.4), and mortality in the ICU was 18%. Patients who were admitted on intervention days were exposed to nighttime intensivists on more nights than were patients admitted on control days (median, 100% of nights [interquartile range, 67-100] vs. median, 0% [interquartile range, 0-33]; p < 0.001). Nonetheless, intensivist staffing on the night of admission did not have a significant effect on the length of stay in the ICU (rate ratio for the time to ICU discharge, 0.98; 95% confidence interval [CI], 0.88-1.09; p = 0.72), ICU mortality (relative risk, 1.07; 95% CI, 0.90-1.28), or any other endpoint. Analyses restricted to patients who were admitted at night showed similar results, as did sensitivity analyses that used different definitions of exposure and outcome.


The authors concluded that nighttime in-hospital intensivist staffing did not improve patient outcomes.


This single-center randomized trial reported that, as compared with nighttime telephone availability of the intensivist, nighttime intensivist staffing had no significant effect on length of stay in the ICU or hospital, ICU or in-hospital mortality, readmission to the ICU, or the probability of discharge to home. It appears that, nighttime intensivist staffing may be one of several expensive practices that have been adopted without a good evidence base. Because the use of nighttime intensivist staffing by hospitals with plentiful resources may pull intensivists away from hospitals with less resources, rigorous evaluation of nighttime intensivists is needed in additional settings that were not evaluated in this study.

Keywords: Intensive Care Units, Personnel Staffing and Scheduling, Hospital Mortality, Personnel, Hospital, APACHE, Cardiology, Telephone, Cardiovascular Diseases, Confidence Intervals, Patient Discharge, Hospitalization, Length of Stay

< Back to Listings