A Commentary on “Effective Dose of Epidural Hydromorphone for Analgesia Following Caesarean Section in Using Modified Dixon Sequential Method” [Response to Letter]
We are deeply honored to receive comments from readers, which demonstrates the significant importance of our research content. We are grateful to Wu et al for carefully reading our article and affirming the research direction. Of course, it’s a pity that they have some small doubts about our methods and results. So next, we will give our reasonable explanation of the questions raised by Wu et al. First of all, the modified sequential method has been used in many studies to explore the concentration and dosing of drugs. The modified sequential method can significantly reduce the average sample size and average trial duration, thereby effectively lowering trial costs. In addition, we mentioned in the article that due to the small sample size of this experiment, further studies are still needed. We made a preliminary exploration to further research on the application of epidural hydromorphone after caesarean section. Second, previous studies have verified the efficacy of epidural hydromorphone analgesia following caesarean section. , According to our results, there was no significant increase in the incidence of side effects in patients after caesarean section, which means that the effects were safe in the appropriate dose range. However, given its analgesic effect comparable to that of morphine and its relatively fewer side effects, , our study builded upon previous research to solely explore its dosage. The comparison with morphine was not our primary focus. Third, we collected the BMI of the parturient and conducted statistical analysis to ensure there was no significant bias, which was showed in the article. Additionally, during pre-anesthesia visit for every pregnant woman who was about to undergo caesarean section, we inquired about any frequently used medications and a history of drug allergies. This is a routine inquiry. Finally, many thanks to Wu et al for their comments, which enriched our research. It provides a very comprehensive overview for better exploration of hydromorphone for postoperative analgesia after caesarean section. 

