Comparing the effect of adding intrathecal morphine or pethidine to bupivacaine in spinal anesthesia during cesarean section surgery on post-operative pain of pregnant women with a gestational age of over 37 weeks

The effect of adding intrathecal morphine or pethidine to bupivacaine spinal anesthesia will be compared in this research.

This randomized two-armed parallel group (55 subjects) trial will be double-blinded. Randomization will be applied by random allocation software.

This study will be performed on pregnant women ready for cesarean section in Bandar Abbas, Iran, in Shariati and Persian Gulf hospitals in the years 2017-2018. Upon approval of the protocol by the Theses Committee of the School of Medicine and the Ethics Committee of the University the participating pregnant women, the second anesthesiologist and the medical student will be blinded. The desired variables will be recorded during the study. After a 10 cc/kg of ringer serum pre hydration, spinal anesthesia will be applied in a sitting position, with a Quincke needle (number.25), at lumbar spaces 3-4 or 4-5 with a total volume of 3 milliliters of anesthetic solution.

Inclusion criteria: Age 18-50, gestational age of over 37 weeks and the American Society of Anesthesiologists physical status classes I and II and candidate for a cesarean section surgery. Exclusion criteria: Emergency cesarean section, Limitations for applying regional block, Valvular heart disease, A history of allergy to the target drugs, Addicts, Alcoholics, Preeclampsia, Diabetes, Unwillingness to take part in the research.

The group 1 will receive 12 mg of bupivacaine (0.5%) plus 200 μg of morphine and group 2 will receive 12 mg of bupivacaine (0.5%) plus 20 mg of pethidine.

Hemodynamic parameters, pain, respiratory rate, sedation, nausea and vomiting, and itching will be recorded.

Random allocation software will be used to design a permuted block randomization table with a 1:1 allocation. Block sizes of 2, 4 and 6 will be used. According to the size of each block concealed opaque sequentially numbered envelopes containing the either assigned group A or B will be drawn. Allocation concealment and blinding to the block sizes will be applied to the primary anesthesiologist responsible for applying the study protocol.

The following group of people involved in the blinding is: The participating parturients involved in the study will not be aware of the type of drug being injected intrathecally. However, written informed consent will be obtained from the participants. A second anesthesiologist who is participating in the trial but is not in charge of patient care will be responsible for collecting data in the operating room and will be blinded to the designation group of the pregnant participants and medications prescribed in the protocol. The medical student responsible for collecting the results of the study will also be blinded to the inclusion of parturients in the groups and the drugs prescribed in the protocol.

All collected deidentified IPD will be available.

Starting 12 months after publication.

This will be only made available for people working in academic institutions.

The requests for review will be answered according to the policies provided by the body of regulations that is stated by the Vice-chancellor of research of Hormozgan University of medical sciences.

Requests can be sent to Dr. Abbas Moellemy at moallemyaln@yahoo.com

The request for deidentified participant data review will be evaluated by the anesthesiology research center vice-chancellor and referred to the Hormozgan university vice-chancellor for assessing the eligibility of the requesting party this may take 1-3 months.