The Median Effective Infusion Rate of Ciprofol with Different Doses of Esketamine During Gastrointestinal Endoscopy: A Randomized Controlled Trial.

PURPOSE: To quantify the dose-dependent ciprofol-sparing effect of adjunctive esketamine and determine its optimal infusion rate regimen in adult patients undergoing gastrointestinal endoscopy.

METHODS

In this randomized, double-blind trial, 90 ASA I-III patients (aged 18-65 years) received ciprofol with esketamine (0.25 mg/kg [SK0.25], 0.5 mg/kg [SK0.5]) or saline (SK0) during combined gastroscopy/colonoscopy. The median effective infusion rate of ciprofol was determined using the modified Dixon's up-and-down method. Hemodynamic parameters and adverse events were systematically assessed.

RESULTS

Adjunctive esketamine significantly reduced ciprofol median effective infusion rate in dose-dependent manner: 0.75 mg/kg/h (95% CI: 0.66-0.85) with saline versus 0.70 mg/kg/h (0.66-0.76; adjusted p < 0.0167) at 0.25 mg/kg esketamine and 0.62 mg/kg/h (0.54-0.70; adjusted p < 0.0167) at 0.5 mg/kg. The esketamine-ciprofol regimen reduced hypotension by 56.7% (16.67% vs 73.33% in controls; adjusted p < 0.0167). Mean arterial pressure (MAP) decline attenuated at 0.5 mg/kg esketamine (ΔMAP: -8.2% vs -14.7% in controls). No severe adverse events occurred. Equivalent sedation (MOAA/S ≤1) was maintained with 45% ciprofol reduction at optimal 0.5 mg/kg esketamine dose.

CONCLUSION

Esketamine (0.5 mg/kg) significantly reduces the ciprofol maintenance infusion rate while enhancing hemodynamic stability during gastrointestinal endoscopy. Under standard monitoring, no hypoxemia occurred in any group. However, specific esketamine-related adverse events, such as neuropsychiatric symptoms and increased secretions, were not systematically assessed, which should be considered when interpreting the clinical safety profile. These findings are based on specific procedural and monitoring protocols; their application to different clinical settings should consider local contexts.