Divya Sujatha Sivadasan1 , Aswathy Sarath2
BACKGROUND Shivering is a very unpleasant, physiologically stressful sensation for the patient undergoing surgery. Spinal anaesthesia impairs the thermoregulatory control, increasing the sweating threshold and decreasing vasoconstriction and shivering threshold.1 The combination of anaesthetic induced thermoregulatory impairment and exposure to a cool environment makes most unwarmed surgical patients hypothermic. Around 40-60% of patients under regional anaesthesia develop shivering.2,3 The aim of this study was to evaluate the efficacy and safety of oral clonidine in the control of shivering in patients undergoing elective urological surgeries under subarachnoid block. METHODS The study was an observational study including 100 patients fulfilling the inclusion criteria who had given a written informed consent. Patients were divided into study and control groups of 50 each with the test group receiving 150 mcg of oral clonidine 90 mins prior to the surgery. Grading of shivering was done as per the grading in the study of Wrench et al (1997) for six 10 min. intervals for first hour of surgery and sedation was assessed using Modified Ramsay Sedation Scale4 for 30 min intervals for the first 3 hours following onset of surgery. RESULTS The overall incidence of shivering was significantly low (p<0.0001) across all the time periods in the Clonidine group. The severity of shivering was also significantly low in Clonidine group across all time periods. No statistically significant difference in sedation was seen among the two groups across all time intervals. CONCLUSIONS Oral clonidine at a dose of 150 µg administered 90 minutes before subarachnoid block in urological surgeries affected a significant reduction in the intensity and severity of post subarachnoid block shivering.
