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.