The 50% effective dose of hydromorphone and morphine for epidural analgesia in the hemorrhoidectomy: a double-blind, sequential dose-finding study.

"Declarations Ethics approval and consent to participateEthical approval for this study was provided by the Ethical Committee of the Dongguan Tungwah hospital (Number: DHKY-2023-003-01). The written informed consents were obtained from all patients before participation. The study was registered at https://www.chictr.org.cn/(01/03/2023) and registration number was ChiCTR2300068847. Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors."

"The Ethics Committee of Dongguan Tungwah hospital approved the study protocol (DHKY-2023-003-01) and registered at https://www.chictr.org.cn/(01/03/2023) and registration number was ChiCTR2300068847. We recruited 100 patients who were hospitalized in Dongguan Tungwah hospital between March 2023 and June 2023 in accordance with the Declaration of Helsinki. Before they underwent elective hemorrhoidectomy at Dongguan Tungwah hospital, the patients were randomly recruited by one of our anesthesiologist as the research subjects, and confirmed that informed consent was obtained from all subjects and/or their legal guardian(s). Each patient was given either epidural morphine or hydromorphone using a computer-generated blocked randomization technique by a research anesthetist using SPSS for Windows version 25 (SPSS Inc., Chicago, IL, USA). At the time of randomization, sealed envelopes containing the group allocation codes were opened. The randomization procedure was carried out and the study medicine was manufactured within 60 min of administration by a blind nurse not engaged in patient consent or data collecting. Put it in another way, the study participants and all researchers were unaware of the specific study group assignments, and treatment dose. Declarations: Ethics approval and consent to participateEthical approval for this study was provided by the Ethical Committee of the Dongguan Tungwah hospital (Number: DHKY-2023-003-01). The written informed consents were obtained from all patients before participation. The study was registered at https://www.chictr.org.cn/(01/03/2023) and registration number was ChiCTR2300068847.: Consent for publicationNot applicable.: Competing interestsThe authors declare no competing interests. Ethics approval and consent to participate: Ethical approval for this study was provided by the Ethical Committee of the Dongguan Tungwah hospital (Number: DHKY-2023-003-01). The written informed consents were obtained from all patients before participation. The study was registered at https://www.chictr.org.cn/(01/03/2023) and registration number was ChiCTR2300068847."