Intravenous dexmedetomidine prolongs bupivacaine spinal analgesia.

BACKGROUND The prolongation of spinal anesthesia by using clonidine through the oral, intravenous and spinal route has been known. The new alpha 2 agonist, dexmedetomidine has been proved to prolong the spinal anesthesia through the intrathecal route. We hypothesized that dexmedetomidine when administered intravenously following spinal block, also prolongs spinal analgesia. METHODS 48 patients were randomly allocated into two equal groups following receiving spinal isobaric bupivacaine 12.5 mg. Patients in group D received intravenously a loading dose of 1 microg/kg dexmedetomidine over 10 min and a maintenance dose of 0.5 microg/kg/hr. Patients in group C (the control group) received normal saline. The regression times to reach S1 sensory level and Bromage 0 motor scale, hemodynamic changes and the level of sedation were recorded. RESULTS The duration of sensory block was longer in intravenous dexmedetomidine group compared with control group (261.5 +/- 34.8 min versus 165.2 +/- 31.5 min, P < 0.05). The duration of motor block was longer in dexmedetomidine group than control group (199 +/- 42.8 min versus 138.4 +/- 31.3 min, P < 0.05). CONCLUSION Intravenous dexmedetomidine administration prolonged the sensory and motor blocks of bupivacaine spinal analgesia with good sedation effect and hemodynamic stability.