The relative contribution of anaesthetists and post-anaesthesia care unit nurses to patient-reported postoperative quality improvement indices

Patient-reported outcomes in the post-anaesthesia care unit (PACU), such as pain, postoperative nausea and vomiting (PONV) and hypothermia, are often used for quality improvement (QI) purposes and to benchmark hospitals and anaesthetists. However, it is unclear whether variations in these measures reflect differences between clinicians or are driven by factors beyond clinician control. The aim of this study was to quantify how much of the variation in patient outcomes of severe pain, PONV and hypothermia in PACU, was associated with individual anaesthetists and PACU nurses, after adjusting for patient and surgical factors. Data from 71,113 adult surgical cases at a single tertiary institution were analysed. PACU outcomes of pain, PONV and hypothermia were assessed using mixed-effect logistic regression models, where clinicians were random effects, and patient and surgical factors were fixed effects. For each outcome, the proportion of variance associated with PACU nurses, after adjustment for patient and surgical factors, exceeded that associated with anaesthetists (pain 2.9% vs 1.1%; PONV 1.9% vs 1.1%; hypothermia 14.2% vs 1.5%). The majority of variation was explained by patient, surgical and unmeasured factors. These findings indicate that the outcomes examined predominantly reflect case-mix and system factors, with little observable variability attributable to individual anaesthetists. Consequently, these outcomes should not be used as performance indicators for anaesthetists, but rather for focused QI projects in targeted patient and surgical groups.