Optimal Intrathecal Morphine Dose for Better Post Cesarean Section Analgesia

Official title

Comparison of Postoperative Analgesia With Different Doses of Intrathecal Morphine With Hyperbaric Bupivacaine and Fentanyl in Cesarean Section Patients: A Randomized Controlled Trial

Overview

Central neuraxial blocks (CNBs) remain the preferred anesthetic technique for cesarean section, with single shot spinal anesthesia (SSSA) being the standard practice at investigator's institute unless contraindicated. SSSA offers reliable intraoperative anesthesia and provides a few hours of postoperative analgesia. Enhanced recovery after cesarean section protocol has recommended the addition of intrathecal (IT) morphine to improve the postoperative quality of the recovery profile. Fentanyl improves the quality of intraoperative analgesia, while morphine significantly prolongs the postoperative pain relief, often lasting up to 24 hours. Routine uterine exteriorization, practiced in all cases at investigator's institute, often results in peritoneal stretching pain during surgery. This visceral pain is managed with 10 mcg intrathecal fentanyl added to hyperbaric bupivacaine. For postoperative pain management, the intrathecal morphine is recommended by many guidelines and studies. Intrathecal morphine dose typically ranges from 50 to 300 mcg. The dose of morphine exceeding 150 mcg are usually associated with prolongation of analgesia with higher incidence of side effects like nausea, vomiting and pruritus. In selected cases, investigator had administered morphine 100-150 mcg and the clinical experience has shown reduced postoperative analgesic requirements and favorable recovery profile, with minimal adverse effects. Despite these promising experiences and extensive literature on IT morphine, their is still lack formal data on the efficacy and safety profile of IT morphine in cesarean section patient. This comparative study will help institute to find the optimum dose of IT morphine with better postoperative analgesia quality with low side effects profile. The finding could serve as a foundation to promote routine use of intrathecal morphine in cesarean section anesthesia at investigator's institute.

Interventions

• Drug 0.5% bupivacaine heavy with fentanyl
  Spinal anesthesia with 0.5% bupivacaine heavy with fentanyl at L3-L4 intervertebral space using Quincke's spinal needle in sitting position in patients undergoing cesarean section to study the dose with better analgesia profile and lower side effect profile.
• Drug 0.5% bupivacaine heavy with fentanyl plus morphine 50 mcg
  Spinal anesthesia with 0.5% bupivacaine heavy with fentanyl with morphine 50mcg at L3-L4 intervertebral space using Quincke's spinal needle in sitting position in patients undergoing cesarean section to study the dose with better analgesia profile and lower side effect profile.
• Drug 0.5% bupivacaine heavy with fentanyl plus morphine100 mcg
  Spinal anesthesia with 0.5% bupivacaine heavy with fentanyl with morphine 100mcg at L3-L4 intervertebral space using Quincke's spinal needle in sitting position in patients undergoing cesarean section to study the dose with better analgesia profile and lower side effect profile.
• Drug 0.5% bupivacaine heavy with fentanyl plus morphine 150mcg
  Spinal anesthesia with 0.5% bupivacaine heavy with fentanyl with morphine 150mcg at L3-L4 intervertebral space using Quincke's spinal needle in sitting position in patients undergoing cesarean section to study the dose with better analgesia profile and lower side effect profile.

Primary outcome measures

• To compare the incidence of postoperative pain after cesarean section with different doses of intrathecal morphine with bupivacaine among the four groups. [Time frame: NRS score is measured in recovery room for postoperative pain assessment. This time will be recorded as "time zero". Then in postoperative ward, NRS score is measured at 2 hours, 4 hours, 6 hours, 12 hours and 24 hours from 'time zero".]

Secondary outcome measures (4)

• To compare the first rescue analgesia demand time among the four groups [Time frame: Postoperative period after cesarean delivery till 24 hour]
• To compare the total analgesic consumption in first 24 hours among the parturient of four group [Time frame: Postoperative total analgesia consumption for first 24 hour]
• To compare the frequency of rescue analgesia demanded by parturient in first 24 hours among the groups [Time frame: Postoperative period for first 24 hour]
• To compare the incidence of side effects like nausea, vomiting, respiratory depression, level of sedation and pruritus in first 24 hours among the groups [Time frame: Postoperative period for first 24 hour]

Eligibility criteria

Inclusion criteria

• Pregnant lady > 36 weeks of gestation presenting for cesarean section under spinal anesthesia
• ASA II/ III
• Maternal Height > 150 cm
• BMI< 40 Kg/m2
• Elective Indication

Exclusion criteria

• Patient unwilling to take part in the study
• Patient with known allergy to the study medications
• Contraindication to Spinal Anesthesia

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Triple blind

Primary purpose

Treatment

Study locations

Center list to be confirmed — check the primary protocol.

Publications

• Sultan P, Halpern SH, Pushpanathan E, Patel S, Carvalho B. The Effect of Intrathecal Morphine Dose on Outcomes After Elective Cesarean Delivery: A Meta-Analysis. Anesth Analg. 2016 Jul;123(1):154-64. doi: 10.1213/ANE.0000000000001255. PMID 27089000
• Choudhury M. Neuraxial anaesthesia in parturient with cardiac disease. Indian J Anaesth. 2018 Sep;62(9):682-690. doi: 10.4103/ija.IJA_474_18. PMID 30237593

Identifiers

NCT: NCT07560501 · IRC/IOM/D-2026-339 · NHRC 772-2025

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗