Comparison of the Effect of Non-Pharmacological Interventions Versus a Combination of Ondansetron and Pethidine on Shivering, Nausea, and Vomiting after Spinal Anesthesia for Cesarean Section

Comparison of the Impact of Non-pharmacological interventions vs. a combination of ondansetron & Pethidine on Shivering & Nausea & Vomiting after spinal Anesthesia for cesarean section

Randomization will be performed using sealed opaque envelopes with variable block randomization, and outcome assessors will be blinded to group allocation.

This study will be conducted at a teaching/specialized hospital affiliated with Ahvaz Jundishapur University of Medical Sciences (with full obstetrics and anesthesia facilities).

Scheduled for elective cesarean section under spinal anesthesia American Society of Anesthesiologists (ASA) physical status I or II Full-term pregnancy (gestational age ≥37 weeks) Body Mass Index (BMI) between 18 and 35 kg/m² Willing to participate and provide written informed consent ​ Patient refusal to participate or withdrawal of consent at any time during the study Emergency cesarean sections Known hypersensitivity or allergy to ondansetron, pethidine, or local anesthetic agents Contraindications to spinal anesthesia (coagulopathy, local infection at puncture site, increased intracranial pressure, severe hypovolemia) Patients with severe cardiovascular, respiratory, hepatic, or renal disorders Pre-existing neurological disorders Baseline hypothermia (core body temperature <35°C) or fever (>38°C) History of chronic pain or regular opioid use Patients on medications affecting thermoregulation or antiemetic medications

Participants will be randomly allocated to one of two groups: (1) the non-pharmacological interventions group or (2) the pharmacological interventions group (ondansetron + pethidine combination)

Incidence and Severity of Shivering and Nausea

In the present study, participants will be allocated to the two intervention groups (non-pharmacological and pharmacological) using block randomization with variable block sizes (4 and 6) via sequentially numbered, sealed, opaque envelopes.

This study will employ a single-blind design. In this design, participants (patients) will be aware of their group allocation due to the tangible nature of the interventions. However, outcome assessors and data analysts will remain blinded to group assignment until the completion of the primary analysis. The principal investigator responsible for administering the interventions and initial data recording will not be blinded due to the practical nature of the interventions.

De-identified individual participant data. This set includes all raw data collected per protocol: baseline demographics, primary outcomes (incidence and severity of shivering, incidence of nausea and vomiting), secondary outcomes (vital signs), and safety data. Data will be shared in a structured Excel or CSV file after removal of all direct identifiers (name, medical record number, phone number) and coding.

Data will become publicly available 12 months after the publication of the primary study results in a peer-reviewed journal and will remain accessible for at least 5 years thereafter.

Access is open to academic researchers and scientists affiliated with credible research or educational institutions, for the purpose of conducting valid scientific secondary analyses or meta-analyses.

Data may only be used for non-commercial research purposes with proper citation of the original study. Requestors must submit a brief scientific analysis proposal (max 1 page) outlining the aims, methods, and intended outputs of the secondary analysis. Use for validation of findings or educational purposes is permitted.

Requests should be submitted via email to the study's corresponding researcher: Title: Assistant/Associate Professor of Anesthesiology Affiliation: Ahvaz Jundishapur University of Medical Sciences

Upon receipt of a formal request and analysis proposal, the Study Data Access Committee will review the request for alignment with the stated purposes and conditions within 4 weeks and communicate its decision via email. If approved, data will be shared within 2 weeks after receiving a signed data use agreement.