Effect of dexmedetomidine added to spinal bupivacaine for urological procedures

OBJECTIVE: To determine the effect of adding dexmedetomidine to bupivacaine for neuraxial anesthesia.

METHODS: Sixty-six patients were studied between April and May 2008 in the University of Jordan, Amman Jordan. They were randomly assigned into 3 groups, each receiving spinal bupivacaine 12.5mg combined with normal saline (group N) Dexmedetomidine 5ug (group D5), or dexmedetomidine 10ug (group D10). The onset times to reach T10 sensory and Bromage 3 motor block, and the regression times to reach S1 sensory level and Bromage 0 motor scale, were recorded.

RESULTS: The mean time of sensory block to reach the T10 dermatome was 4.7 ± 2.0 minutes in D10 group, 6.3±2.7 minutes in D5, and 9.5±3.0 minutes in group N. The mean time to reach Bromage 3 scale was 10.4±3.4 minutes in group D10, 13.0±3.4 minutes in D5, and 18.0±3.3 minutes in group N. The regression time to reach S1 dermatome was 338.9±44.8 minutes in group D10, 277.1±23.2 minutes in D5, and 165.5±32.9 minutes in group N. The regression to Bromage 0 was 302.9±36.7 minutes in D10, 246.4 ±25.7 minutes in D5, and 140.1±32.3 minutes in group N. Onset and regression of sensory and motor block were highly significant (N vesus D5, N versus D10, and D5 versus D10, p<0.001).

CONCLUSION: Dexmedetomidine has a dose dependant effect on the onset and regression of sensory and motor block when used as an adjuvant to bupivacaine in spinal anesthesia.