The Influence of age on sensitivity to Dexmedetomidine sedation during Spinal Anaesthesia in Infra Umbilical Surgeries

Abstract

Background: Dexmedetomidine is a highly selective alpha 2 adrenergic receptor agonist that has been used for sedation under spinal anaesthesia. The aim of this study was to evaluate the influence of age on sensitivity to dexmedetomidine sedation in adult patients scheduled for infra umbilical surgery under spinal anaesthesia to identify dexmedetomidine ED50 for adequate sedation among different age groups.Material & Method: In this study, 90 patients of ASA grade I and II, between 18-79 years of age scheduled for infra umbilical surgery under spinal anaesthesia were recruited and randomly allocated into three age groups (30 in each) young age group (18-40yrs), middle-age groups (41-60yrs) and elderly age group (61-79yrs). After a spinal anaesthesia loading dose of dexmedetomidine @ 1mcg/kg for the young and middle age group and 0.7mcg/kg for the elderly age group was administered over 15 minutes. Dixon’s up-and-down method was used to determine the ED50 of the drug for adequate sedation. We assessed the depth of sedation with the Ramsay sedation scale and measured vital signs and oxygen saturation.Result: ED50 in the elderly group was lower than the other 2 groups (elderly: 0.66 ± 0.04; middle aged: 0.80 ± 0.07; young: 1.12 ± 0.06μg/kg; both P < .001). Bradycardia and Hypotension were more common in elderly patients.Conclusion: Elderly patients are more sensitive to dexmedetomidine sedation as compared to younger patients