Effect of nurse-to-patient ratio in the intensive care unit on pulmonary complications and resource use after hepatectomy

BACKGROUND: Nurse-to-patient ratios in the intensive care unit are associated with postoperative mortality, morbidity, and costs after some high-risk surgery. OBJECTIVE: To determine if having 1 nurse caring for 1 or 2 patients ("more nurses") versus 1 nurse caring for 3 or more patients ("fewer nurses") in the intensive care unit at night is associated with differences in clinical and economic outcomes after hepatectomy. METHODS: Statewide observational cohort study of 569 adults who had hepatic resection, 1994 to 1998. Hospital discharge data were linked to a prospective survey of organizational characteristics in the intensive care unit. Multivariate analysis was used to determine the association of nighttime nurse-to-patient ratios with in-hospital mortality, length of stay, hospital costs, and specific postoperative complications. RESULTS: A total of 240 patients at 25 hospitals had fewer nurses; 316 patients in 8 hospitals had more nurses. No significant association between nighttime nurse-to-patient ratios and in-hospital mortality was detected. The overall complication rate was 28%. By univariate analysis, patients with fewer nurses had increased risks for pulmonary failure (5. 8% vs 1. 6%, relative risk, 3. 6; 95% CI, 1. 3-10. 1; P=. 006) and reintubation (10. 8% vs 1. 9%, relative risk, 5. 7; 95% CI, 2. 4-13. 7; P<. 001). By multivariate analysis, patients with fewer nurses had increased risk for reintubation (odds ratio, 2. 9; 95% CI, 1. 0-8. 1; P=. 04) and a 14% increase (95% CI, 3%-23%; P=. 007) or an additional 1248 (95% CI, 384-2112; P =. 005) in total hospital costs. CONCLUSIONS: Fewer nurses at night is associated with increased risk for specific postoperative pulmonary complications and with increased resource use in patients undergoing hepatectomy.