Dosage of Intrathecal Hyperbaric Bupivacaine and the Incidence of Post Spinal Shivering.

Shivering is very common after spinal anaesthesia. Many studies have investigated the role of adding adjuvants to the local anaesthetics to decrease the incidence of post-spinal shivering. Non of the studies n the literature review have investigated the role of different dose of local anaesthetic alone in reducing the incidence of post-spinal shivering. In the present study the investigators aimed to compare the effect of different local anaesthetic dose in reducing post-spinal shivering.

After approval of the ethics committee, department of anaesthesia, Menoufia University and written informed consent, a hundred full-term pregnant ladies undergoing elective cesarean section were enrolled in this study. The pregnant ladies were randomly assigned using a computerised software to one of two groups, low dose bupivacaine (LB) and high dose bupivacaine (HB), 50 patients each according to bupivacaine dose. Group LB received low dose bupivacaine (8 mg hyperbaric bupivacaine) Group HB received high dose bupivacaine (10 mg hyperbaric bupivacaine). Vital signs including heart rate and mean arterial blood pressure intra-operatively until the end of surgery. The severity of shivering was the primary endpoint. Shivering was graded using a scale: 0, no shivering; 1, piloerection but no visible muscle activity; 2, muscular activity in one group of muscle; 3, muscular activity in more than one muscle group but not generalized movement; and 4, shivering involving the movement of the whole body. Shivering score was recorded for the whole study period.