Background: Post-spinal shivering poses a common challenge following regional anesthesia, presenting patients with an undesirable and distressing experience, and potentially leading to various complications. This study aimed to investigate the efficacy of intravenous midazolam, midazolam-ketamine, and ketamine in reducing the incidence of post-spinal shivering.

Methods and materials: A double-blind clinical trial was conducted on 124 patients aged 18-40 undergoing cesarean section with spinal anesthesia at Fatemieh Hospital, Hamadan. Spinal anesthesia was induced with 0.5% bupivacaine (10 mg) plus 2.5 μg sufentanil. Patients were randomly assigned to four groups: Midazolam 0.075 mg/kg (Group A), Ketamine 0.5 mg/kg (Group B), Ketamine 25.0 mg/kg plus Midazolam 37.5 μg/kg (Group C), and Normal saline 0.9% (Group D). Shivering severity, hemodynamic effects, nausea and vomiting, arterial oxygen saturation, hallucinations, sedation, and pethidine consumption were recorded during surgery and recovery.

Results: There were no statistically significant differences in shivering severity among the four groups. Additionally, no significant disparities were observed in hallucination occurrence or pethidine consumption. However, notable physiological changes were noted, including reductions in systolic and diastolic blood pressure, mean arterial pressure, and arterial oxygen saturation across all groups. Moreover, the midazolam-ketamine group exhibited increased heart rate and sedation scores, along with a higher incidence of nausea and vomiting. These findings highlight the diverse effects of the interventions on various physiological parameters and patient experiences.

Conclusion: Prompt administration of pharmacological agents following regional anesthesia may offer a more effective approach to prevent post-spinal shivering.