Abstract
PURPOSE: Obesity is associated with an elevated risk of hypoxemia during endoscopic procedures performed under anesthesia. However, whether the sequence of drug administration - specifically the order of propofol and remifentanil - affects the incidence of hypoxemia remains unclear. This study was designed to evaluate whether a novel administration sequence, in which propofol precedes remifentanil, can decrease the incidence of hypoxemia in obese individuals during endoscopy. PATIENTS AND METHODS: This prospective, single center, randomized controlled clinical trial recruited 296 obese patients scheduled for sedative/anesthesia gastroscopy prior to bariatric surgery. Patients were randomly assigned to either novel administration sequence with propofol-remifentanil (P-R) group or conventional administration of remifentanil-propofol (R-P) group. The primary outcome was the incidence of hypoxemia. Secondary outcomes included the lowest peripheral oxygen saturation (L-SpO(2)) during the procedure, hemodynamic parameters at six time points, and additional perioperative events. RESULTS: 284 patients were included in the analysis with 142 in each group. Hypoxemia occurred in 22 patients (15.5%) in the P-R group, and 42 patients (29.6%) in the R-P group (Relative Risk [RR], 1.44; 95% confidence interval [CI], 1.13 to 1.79; P = 0.007). The L-SpO(2) during the procedure was significantly higher in the P-R group than in the R-P group (median [interquartile range, IQR], 94.0% [91.0 to 97.0] vs 93.0% [87.7 to 95.0]; P < 0.001). The P-R sequence technique was also associated with more stable hemodynamic profiles, shorter induction time, the start of drug administration to scope insertion and recovery time, improved patient's satisfaction. Particularly, minimal respiratory depression was observed in subgroups such as body mass index (BMI) ≥ 40 kg/m(2). CONCLUSION: Propofol first and followed by remifentanil administration sequence significantly decreased the incidence of hypoxemia and increased the L-SpO(2) in obese patients for their anesthesia/sedation gastroscopy. CLINICAL TRIAL REGISTRATION: ChiCTR2400084998.