Low-dose remimazolam plus remifentanil vs placebo plus remifentanil during gastroscopy in adults with obesity: A randomized trial

BACKGROUNDPatients with obesity have reduced oxygen reserve and increased susceptibility to upperairway obstruction during sedated gastroscopy.Evidence on the incremental benefit of adding low-dose remimazolam to remifentanil remains limited. AIMTo evaluate the effect of low-dose remimazolam added to remifentanil on gastroscope insertion tolerance, rescue remifentanil use, and respiratory safety in adults with obesity. METHODSThis single-center, randomized, placebo-controlled trial enrolled 110 adults with obesity.Participants received remimazolam 0.04-0.05mg/kg or volume-matched saline placebo, followed by remifentanil 1 μg/kg, with doses based on adjusted body weight.The primary modified intention-to-treat analysis included 106 participants (trial, n = 54; control, n = 52).The primary outcome was successful gastroscope insertion without body movement, coughing, or retching during insertion or within 1 minute thereafter.Sensitivity analyses included all 110 randomized participants, and respiratory safety was assessed in all 110 treated participants. RESULTSSuccessful insertion without response occurred in 44/54 (81.5%) participants in the trial group and 33/52 (63.5%) in the control group [risk difference: 18.0%; 95% confidence interval: 1.0-33.9;relative risk (RR): 1.28; P = 0.0499].Rescue remifentanil was required in 13.0% vs 48.1% of participants, respectively.Sensitivity analyses in all randomized participants showed a consistent direction of effect.In the all-treated population, casereport form-recorded (CRF-recorded) peripheral oxygen saturation (SpO 2 ) < 95% 4 / 33 occurred in 56.4% vs 29.1% (RR: 1.94; raw P = 0.0067; Holm-adjusted P = 0.0668), whereas scheduled four-time-point nadir SpO 2 < 95% was similar between groups (27.3% vs 23.6%; P = 0.8270).Protocol-defined hypoxemia and mask ventilation were uncommon. CONCLUSIONAdding low-dose remimazolam to remifentanil improved gastroscope insertion tolerance and reduced rescue remifentanil use in adults with obesity.Because CRFrecorded desaturation was more frequent with the combined regimen, close oxygenation monitoring and timely airway support remain important.