Higher nurse staffing levels are significantly associated with a lower relative risk of dying in the hospital, according to an exhaustive metaanalysis conducted for the Agency for Healthcare Research and Quality. Adding one "full-time equivalent" (FTE) RN per patient day reduced the relative risk of in-hospital death by 9% in ICU patients and 16% in surgical patients. One additional FTE RN was also associated with a 24% shorter stay in ICUs and a 31% shorter stay among surgical patients. More nurse time per patient was associated with lower rates of failure to rescue, cardiac arrest, pulmonary failure, and unplanned extubation in a number of studies.

Mortality rates were as much as 34% lower when a greater proportion of a hospital's nursing staff had a baccalaureate. Nurses' job satisfaction and autonomy in making patient-care decisions were also associated with lower mortality rates, but years of experience were not.

Studies that examined total nursing hours per patient day and those that used nurse-to-patient ratios to measure nurse staffing showed the same general trends in impact on patient outcomes, but their results were inconsistent and differed according to the method used to measure nurse staffing. Hospitals using more consistent ways to measure staffing would make future study results easier to interpret and apply. The full report is available at http://www.ahrq.gov/clinic/tp/nursesttp.htm.

Fran Mennick, BSN, RN