Abstract
Background: a2-agonist prolongs the duration of intrathecally administered local anaesthetics. This study was planned to investigate the effects of 45 µg and 90µg clonidine added to 0.5% intrathecal hyperbaric bupivacaine for postoperative analgesia.
Materials and Methods: This prospective study was conducted in 90 patients of ASA grade I and II, both sex and aged between 20-60years. Patients were randomly allocated to Group A receiving normal saline+bupivacaine, Group B receiving a combination of 45µg clonidine+bupivacaine and Group C receiving combination of 90µg clonidine+bupivacaine. Sensory block, Motor block, sedation score and hemodynamic parameters were recorded.
Results: Time for onset of sensory block (2.9±0.78 min) and motor block (6.27±0.98 min) was significantly lowest in group C (2.9±0.78 min). (p<0.01) The duration of analgesia was significantly higher in group C (495.33±34.2 min) (p<0.05). The motor block was most prolonged and intense in group C (2.0±0.0 score at 1.5 hr). Maximum sedation was seen at the end of 3 hrs with mean score of 2.1±0.37 in group C as compared to 2.1±0.3 in group B and 1.06±0.2 in Group A. There was no significance difference between the groups for fall of blood pressure. Hypotension and bradycardia were significantly higher in group B and group C as compared to group A, but was within acceptable limits.
Conclusion: Intrathecal 90 µg clonidine seems to be the optimum safe dose because it significantly prolongs postoperative analgesia and markedly decreases supplementary analgesic demand with minimum hemodynamic changes.