This randomized controlled study investigated the benefits and safety of propofol versus ciprofol in improving respiratory depression during anesthesia for elective ERCP procedures. The results indicated that, compared to propofol, ciprofol significantly reduced the incidence of respiratory depression during ERCP, shortened induction time, and even alleviated intraoperative blood pressure and heart rate fluctuations. Furthermore, multivariate logistic regression analysis showed that fasting time, propofol, and Mallampati classification were independent risk factors for the occurrence of respiratory depression.

Intravenous anesthesia serves as a routine anesthetic method for ERCP procedures, effectively mitigating the stress response associated with the manipulation through the oropharynx, cardia, and into the duodenum to reach the ampulla of Vater [12, 13]. Compared with general anesthesia, intravenous anesthesia improves surgical safety and patient comfort [14]. Although propofol is widely used for sedation during endoscopic examinations, it presents notable limitations, including inter-individual variability in pharmacokinetics and pharmacodynamics, respiratory depression, hypotension, and the lack of an effective antagonist [15]. Ciprofol, a novel intravenous anesthetic agent, shares similar characteristics with propofol, such as rapid onset, no accumulation, and quick recovery [5]. During ERCP, the BIS, which reflects the depth of anesthesia, is utilized for guidance. By maintaining the BIS value between 50 and 60, the infusion rate of ciprofol can be effectively controlled, preventing excessive drug concentration and overly deep anesthesia that could interfere with the assessment of potential perioperative adverse events [16, 17].

Respiratory depression is one of the common adverse events associated with sedation. Our study demonstrated that the incidence of respiratory depression (3.3% vs. 9.8%, p = 0.035) and hypoxemia (2.0% vs. 9.0%, P = 0.010) was significantly lower in the ciprofol group compared to patients sedated with propofol. These findings suggest that, relative to propofol, ciprofol may exert a lesser impact on respiratory center depression and airway compromise, thereby maintaining a more stable respiratory state in patients. Additionally, the incidence of injection pain was notably lower in the ciprofol group (8.5% vs. 22.2%, p = 0.001), a finding consistent with previous research [18, 19]. During the operation, both groups exhibited a higher incidence of body movement (17.6% vs. 20.9%, p = 0.56), particularly during periods of intense stimulation, such as when the duodenum or bile duct was stretched. However, this difference was not statistically significant. Postoperative follow-up revealed that none of the patients experienced intraoperative awareness. Injection pain is a common side effect of propofol, and its mechanism may be related to increased vascular permeability, differences in drug pH, and local inflammatory responses [20]. In this study, 34 patients (22.2%) in the propofol group experienced injection pain, while only 13 patients (8.5%) in the ciprofol group reported the same, a significantly lower incidence. This finding is consistent with previous studies [9, 21].

This study observed changes in MAP and HR at different time points in two groups of patients. At T0 and T6, there were no significant difference in MAP between the groups. However, during anesthesia (T1-T5), patients in the P group who received propofol exhibited a pattern of MAP decreasing followed by an increase, with HR showing similar fluctuations. This suggests that propofol anesthesia may lead to significant intraoperative variations in blood pressure and heart rate. Previous study indicates that propofol, being a highly lipophilic agent, rapidly binds to postsynaptic γ-GABAA receptors, enhancing GABA’s effect to inhibit the central nervous system, leading to deep sedation [22]. During the procedure, the P group’s MAP and HR experienced a decrease followed by a recovery, which may be attributed to initial vasodilation and myocardial depression caused by propofol, followed by the waning of the drug’s effects and the activation of homeostatic mechanisms. Therefore, ciprofol has a smaller impact on the circulatory system compared to propofol, leading to more stable hemodynamics during anesthesia. This finding is consistent with previous studies [23, 24].

Previous studies have shown that prolonged fasting before surgery can lead to insulin resistance, increased breakdown of protein and glycogen, and a negative nitrogen balance in the body, so patients are more likely to experience symptoms of fatigue or weakness [25, 26]. A randomized controlled study by Meng et al. showed that fasting time before ERCP increased patients’ fatigue level [27]. In our study, due to the elective ERCP surgery, the fasting time of patients was more than 8 h, and the fasting time was an independent risk factor for respiratory depression during ERCP surgery, and the fasting time increased the incidence of respiratory depression in patients during the operation. It is possible that fasting time increases the patient’s symptoms of fatigue or weakness and increases the likelihood of intraoperative respiratory depression.

This study has several limitations. Firstly, this was a single-center study conducted at the Surgical Endoscopy Center of the First Hospital of Lanzhou University, which may limit the generalizability of our findings to other clinical settings or patient populations. Secondly, although we aimed to control for confounding variables through multivariable logistic regression analysis, residual confounding cannot be entirely ruled out due to the inherent limitations of studies. Lastly, the subjective assessment of outcomes such as body movement and hypoxemia could introduce bias if inter-rater reliability was not systematically evaluated. Future multi-center trials with larger sample sizes and more rigorous blinding protocols are warranted to confirm our findings and address these limitations.