Risk Index for Predicting Supplemental Oxygen Requirement upon Discharge from Postanesthetic Care in Adult Spinal Surgery Patients: A Single-Center Study

Introduction: In recent years, a greater number of adults have been undergoing spinal surgery. The main complications in the postanesthetic care unit (PACU) include respiratory and cardiovascular problems, pain, and nausea or vomiting. The aim of this study was to describe the preoperative characteristics and intra-anesthetic management of adult patients who underwent elective spinal surgery with balanced general anesthesia and to identify the predictive factors associated with supplemental oxygen requirement upon discharge from the PACU. In addition, we sought to develop a risk index on the basis of multivariable analysis allowing stratification of the probability of supplemental oxygen requirement upon discharge from the PACU. Materials and Methods: In this cross-sectional, retrospective, observational study, the pre- and intra-anesthetic characteristics of adult patients who underwent spinal surgery at any vertebral level under balanced general anesthesia in a tertiary hospital were retrieved. Descriptive statistics are provided, and comparison (Kruskal–Wallis) or correlation analyses (chi-square) were conducted between the characteristics of the patients grouped according to the need for supplemental oxygen upon discharge from the PACU. Receiver operating characteristic (ROC) curves and a multivariate logistic regression model were generated. All tests were performed at the α = 0.05 level. Results: Among 349 patients initially considered, only 211 were included in the analysis. A total of 45.50% of the patients who underwent spinal surgery under balanced general anesthesia required supplemental oxygen upon discharge from the PACU; these patients had significantly greater age, body mass index (BMI), surgery time, and anesthesia time. In addition, the use of norepinephrine and the use of fentanyl were associated with the need for supplemental oxygen. Our proposed risk index for predicting the need for supplemental oxygen upon discharge from the PACU, according to the implementation of a multivariable logistic model based on three simple variables (age ≥ 48 years, BMI ≥ 26.5, and use of fentanyl infusion), achieved an area under the curve (AUC) of 0.740. Conclusions: Age, BMI, and the use of fentanyl can be used to predict the need for supplemental oxygen upon discharge from the PACU. Multicenter and/or longitudinal studies with large sample sizes are needed to confirm the results of this study and improve the prediction of the need for supplemental oxygen upon discharge from the PACU.