title: In Spinal Anaesthesia for Cesarean Section the Temperature of Bupivacaine Affects the Onset of Shivering but Not the Incidence: A Randomized Control Trial.
abstract: BACKGROUND
  Postoperative shivering is a frequent event after cesarean section under spinal anaesthesia. Shivering is uncomfortable for the patient and may interfere with monitoring. The exact aetiology of shivering is unknown and therefore has no definite treatment.
  
  
  OBJECTIVE
  The temperature of injectate affects the spread of drug and so its effect. Therefore the aim of this study was to compare the effect of temperature of bupivacaine on post-spinal shivering in cesarean section.
  
  
  METHODS
  In this prospective, randomized, controlled, double-blind clinical trial 105 ASA-I/II pregnant women scheduled for caesarean section under spinal anaesthesia were selected and randomized into three groups of 35 each. In all pregnant women spinal anaesthesia was achieved with 2.2 ml of 0.5% hyperbaric bupivacaine given either at L3-L4 or L4-L5 interspace. The temperature of bupivacaine was adjusted to 4°C (group T4), 22°C (group T22) and 37°C (group T37). Shivering characteristic, onset and incidence was noted. All three groups were compared using analysis of variance (ANOVA), adverse effects was compared using chi-square test and Kruskal-Wallis H-test. The p-value < 0.05-considered as significant and p-value <0.01-considered highly significant.
  
  
  RESULTS
  There were no differences between the groups regarding age, weight, height, amount of fluid used and blood loss. The incidence of shivering was 51.42%, 51.42% and 45.71% in group T4, group T22 and group T37 respectively, this difference in the incidence was statistically not significant (p=0.858). However, the onset of shivering was earliest (9.87±1.82 min) in group T4 as compared to 14.27±3.02 min and 12.16±2.89 min in group T22 and group T37 respectively and this difference in the onset was highly significant (p= 0.0001).
  
  
  CONCLUSIONS
  In spinal anaesthesia for cesarean section, the temperature of bupivacaine does not influence the overall incidence of post spinal shivering; however cold bupivacaine can provoke early onset of shivering.
authors.affiliation: Senior Resident, Department of Anaesthesiology, Himalayan Institute of Medical Sciences, SRH University , Dehradun Uttarakhand, India .
authors.forename: Nand
authors.initials: N
authors.lastname: Kishore
authors.affiliation: Professor, Department of Anaesthesiology, Himalayan Institute of Medical Sciences, SRH University , Dehradun Uttarakhand, India .
authors.forename: Yashwant Singh
authors.initials: YS
authors.lastname: Payal
authors.affiliation: Assistant Professor, Department of Anaesthesiology, Himalayan Institute of Medical Sciences, SRH University , Dehradun Uttarakhand, India .
authors.forename: Nidhi
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Associate Professor, Department of Obstetrics and Gynaecology, Himalayan Institute of Medical Sciences, SRH University , Dehradun Uttarakhand, India .
authors.forename: Nidhi
authors.initials: N
authors.lastname: Chauhan
keywords: Cold bupivacaine; Hypothermia; Post spinal shivering