Prevalence of shivering lower with intrathecal bupivacaine with fentanyl compared to bupivacaine alone in patients undergoing cesarean

The human body has a core temperature that typically falls between the range of 36.5°C to 37.5°C. The core temperature is regulated by the autonomic nervous system via the implementation of behavioral and physiological modifications. The administration of spinal anesthetic has been shown to have negative effects on vasoconstriction below the blocked segments, as well as on the transfer of body heat from the central to peripheral regions. This might result in intraoperative core hypothermia. The present research aimed to evaluate the effectiveness of incorporating a low dosage of fentanyl intrathecally (12.5 μg) in mitigating the incidence of intraoperative shivering and hypothermia, while also documenting any noteworthy adverse effects within this specific group of patients.

The present study included a sample of 148 individuals who had cesarean section while under spinal anesthesia, using a randomized controlled trial design. A total of 148 patients were included in the study, with 74 patients receiving spinal anesthetic using 1.8 mL of hyperbaric bupivacaine (0.5%), while the other 74 patients were provided 12.5 μg of intrathecal fentanyl along with 1.8 mL of hyperbaric bupivacaine. A comparison was conducted between the two groups to determine the occurrence of shivering, as well as the changes in nasopharyngeal and peripheral temperature. Additionally, the temperature at the commencement of shivering and the severity of shivering were also assessed.

The prevalence of shivering was found to be 9.46% in the group receiving intrathecal bupivacaine with fentanyl, which was considerably lower compared to the group receiving intrathecal bupivacaine alone (41.89%). Both groups had a declining trend in nasopharyngeal and peripheral temperature, with the simple bupivacaine group demonstrating higher values.

The present investigation demonstrates that the administration of 12.5 mcg of intrathecal fentanyl as an adjuvant in the subarachnoid block effectively mitigates shivering without eliciting any adverse effects, including pruritus, nausea, vomiting, unfavorable newborn outcomes, or respiratory depression. The observed decrease in shivering, despite similar core temperatures in both groups, may be related to the administration of fentanyl. Fentanyl has been shown to lower the temperature threshold for shivering via its impact on the central nervous system.

Reference –

Thakur, Niraj; Balachander, Hemavathi; Rudingwa, Priya; Panneerselvam, Sakthirajan. Shivering and changes in body temperature in patients undergoing caesarean section under spinal anaesthesia with bupivacaine vs bupivacaine and fentanyl: A randomized clinical study. Journal of Anaesthesiology Clinical Pharmacology 39(1):p 67-73, Jan–Mar 2023. | DOI: 10.4103/joacp.joacp_156_21