Nurse staffing practices and postoperative atrial fibrillation among cardiac surgery patients: A multisite cohort study

Abstract

ABSTRACT Background Postoperative atrial fibrillation (POAF) is a frequent complication of cardiac surgery associated with increased morbidity, mortality, and costs. Recent studies suggest that nurse staffing practices are associated with adverse postoperative events, but whether these practices are also related to POAF occurrence is unknown. Methods To fill this knowledge gap, a cohort of 6,401 cardiac surgery patients admitted to two Canadian university health centers (UHCs) between 2014 and 2018 was studied. Patients’ cumulative exposure to four staffing practices (registered nurse [RN] understaffing, education, experience and non-RN skill mix) was measured every shift over the first six postoperative days, where 96% of POAF cases occur. The associations of these exposures with in-hospital POAF occurrence were estimated using site-specific multivariable logistic regression models and a mixed-effect model combining data from both sites. Results Overall, 563 (27.2%) and 1,336 (30.8%) cases of POAF occurred at UHCA and UHCB, respectively. In site-specific models, every 5% increase in the cumulative proportion of understaffed shifts over the first six postoperative days was associated with a 3.5% increase in the odds of POAF (aOR UHCA: 1.035; 95%CI: 1.000-1.070, p\u202f=\u202f0.0472; aOR UHCB: 1.035; 95%CI: 1.013-1.057, p\u202f=\u202f0.0019). In the mixed-effect model combining data from both sites, RN understaffing remained significant and was associated with a 3.1% increase in the odds of POAF (aOR: 1.031; 95%CI: 1.014-1.048, p\u202f=\u202f0.0003). No other staffing practices were significantly associated with POAF occurrence. Conclusion Higher RN understaffing postoperatively is associated with increased POAF occurrence among cardiac surgery patients.