Levobupivacaine is the oure S(-)-enantiomer of racemic bupivaciane but is less toxic to the heart and central nervous system. Previous studies have shown that it is of equal potency with Bupivacaine in terms of onset of motor blockade, duration of sensor and motor blockade but a significant delay in the onset motor blackade (21 min versus 10 min). one study was done where aspirated CSF was used instead of adding sodium bicarbonate to adjust the pH-adjusted Levobupivacaine0.5% for spinal anesthesia. Thirty patients undergoing elective minor surgery received either 15mg of Levobupivacaine 0.5% isobaric or solution of 15mg of Levobupivacaine 0.5% isobaric with 1:1 mixture of aspirated CSF. Time of motor block onset and pH level were measured in both groups. Results showed faster motor block onset for pH-adjusted Levobupivacaine (1.87 +/- 0.65min versus 18.70 +/-3.26min) and pH level was also higher (7.12 +/-0.05 versus 6.04 +/-0.28). we conclude that the alkalinization by addition of CSF to Levobupivacaine 0.5% via 1:1 mixture speeds the onset motor block. Time to reach a Bromage score from 0 to 3 was shorter and pH level was more basic from the pH-adjusted Levobupivacaine, which may explain the faster onset since pH of the solution was closer to the pKa of Levobupivacaine.
Human ; LEVOBUPIVACAINE ; ANESTHETICS, LOCAL ;