RESUMO
OBJECTIVES: The mortality rate for mechanically ventilated older adults in ICUs is high. A robust research literature shows a significant association between nurse staffing, nurses' education, and the quality of nurse work environments and mortality following common surgical procedures. A distinguishing feature of ICUs is greater investment in nursing care. The objective of this study is to determine the extent to which variation in ICU nursing characteristics-staffing, work environment, education, and experience-is associated with mortality, thus potentially illuminating strategies for improving patient outcomes. DESIGN: Multistate, cross-sectional study of hospitals linking nurse survey data from 2006 to 2008 with hospital administrative data and Medicare claims data from the same period. Logistic regression models with robust estimation procedures to account for clustering were used to assess the effect of critical care nursing on 30-day mortality before and after adjusting for patient, hospital, and physician characteristics. SETTING: Three hundred and three adult acute care hospitals in California, Florida, New Jersey, and Pennsylvania. PATIENTS: The patient sample included 55,159 older adults on mechanical ventilation admitted to a study hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients in critical care units with better nurse work environments experienced 11% lower odds of 30-day mortality than those in worse nurse work environments. Additionally, each 10% point increase in the proportion of ICU nurses with a bachelor's degree in nursing was associated with a 2% reduction in the odds of 30-day mortality, which implies that the odds on patient deaths in hospitals with 75% nurses with a bachelor's degree in nursing would be 10% lower than in hospitals with 25% nurses with a bachelor's degree in nursing. Critical care nurse staffing did not vary substantially across hospitals. Staffing and nurse experience were not associated with mortality after accounting for these other nurse characteristics. CONCLUSIONS: Patients in hospitals with better critical care nurse work environments and higher proportions of critical care nurses with a bachelor's degree in nursing experienced significantly lower odds of death.