Study of dexmedetomidine in hypertension patients undergoing subarachnoid block

Objective To investigate the effect of dexmedetomidine(DEX) on sedation and on the cardiovascular and respiratory system responseses in hypertension patients undergoing total hip replacement with subarachnoid block.Methods Forty hypertension patients(ASAII-III) aged 34～82 years old undergoing total hip replacement were randomized equally into two groups,midazolam group(M group) and dexmedetomidine group(D group).The patients in the midazolam group were administrated 10min preoperatively with 30/kg midazolam then received continuous infusion of midazolam at the rate of 0.05mg/(kg·h),the patients in the dexmedetomidine group were administrated 10min preoperatively with 1μg/kg dexmedetomidine then received continuous infusion of dexmedetomidine at the rate of 0.5μg/(kg·h).Ramsay sedation scale,Blood pressure,Heart rate(HR) and SpO2 were recorded prior to anesthesia,10min after administration,5min,30min and 90min after anaesthesia.Results There was no significant difference in SBP、DBP、HR at prior to anesthesia both of groups(P0.05).SBP、DBP、HR at 10min after administration,5min,30min and 90min after anaesthesia significantly decreased than that at prior to anesthesia both of groups(P0.05) but comparison between the two groups SBP、DBP had no significant difference(P0.05).HR of D group at 10min after administration,5min,30min and 90min after anaesthesia significantly decreased than M group(P0.05).The incidence rate of respiratory inhibition was lower in the dexmedetomidine groups compared with the M group(P0.05),but the incidence rate of bradycardia was higher in D group compared with the M group(P0.05).Conclusion Circulation is stabilize in hypertension patients undergoing total hip replacement with subarachnoid block by dexmedetomidine administrated with sedation and center depressurization and no respiratory inhibition,which is safe for sedation in hypertension patients undergoing total hip replacement with subarachnoid block.