ORAL CLONIDINE AS A PREMEDICATION IN SPINAL ANESTHESIA: EFFECTS ON THE DURATION OF BLOCK AND HEMODYNAMIC STATUS A RANDOMIZED DOUBLE BLIND CLINICAL TRIAL

Introduction. Valuable effects of oral clonidine hemodynamic instability during general anesthesia and prolongation of spinal anesthesia were approved in previous studies. In this study, the effects of clonidine as an oral premedication on the duration of block, hemodynamic status and ephedirine requirements in patients undergoing spinal anesthesia, has been evaluated.
 Methods. In a double blind controlled clinical trial, sixty patients of ASA class I and II, who were candidates for spinal anesthesia for lower abdominal and lower extremity surgical procedures of less than 90 minutes duration, were randomly divided into two equal groups. In interventional group, clonidine and in another control group placebo, was taken orally, 90 minutes before begining of operation. Blood pressure and pulse rate in predetermined times, the amounts of ephedrine being used, duration of sensory and motor blocks and the block level were compaired.
 Results. Mean changes in MAP and pulse rate at 10 minutes before and 10 minutes after induction of spinal anesthesia from basic values in the study group was more than control group (P < 0.05). Mean duration of sensory and motor block in the study group was more than the control group (P < 0.001). Mean of the ephedrine requirements in the study group (5.47 ± 7.5rng) was more than the control group (1.9 ± 4.97mg) (P < 0.05). Block levels was the same (P > 0.05).
 Discussion. It is implicated that the effect of oral clonidine premedication in prolongation the block time in spinal anesthesia is almost conclusive. But regarding more hemodynamic flactuations in the study group, the results of this study was different from studies that performed with general anesthesia. This may be due to additive effects of spinal anesthesia or inappropriate dose of clonidine. More ephedrine requirements in the study group was due to more hemodynamic instability in this group which may be decreased by modifying the clonidine dose. It is suggested that for the routine use of oral clonidine in spinal anesthesia, further evalutions with greater number of patients and various doses of clonidine is necessary