[The effect of the local anesthetic temperature on spinal anesthesia using 0.5% bupivacaine].

The aim of this study was to compare spinal anaesthesia with 0.5% bupivacaine at 20 degrees C and 5 degrees C. One hundred two patients ASA I-II were randomized into two groups. After atropine and IV fluid administration, patients of group I received intrathecally at L3-L4 level 0.02 ml.cm-1 of plain 0.5% bupivacaine at 20 degrees C, while patients of group II received the same solution and the same doses but at 5 degrees C. No significant difference was found between the times for installation of sensory and motor blocks nor between the durations of motor block in the two groups. On the other hand significant differences were found between the durations of sensory block in group I (283.33 min +/- 9.40 min) and group II (314.35 +/- 8.80 min) (P < 0.001) and all the more (P < 10(-9)) between the cephalad block extensions in group I (D 7.45 +/- 0.14) and group II (D 4.82 +/- 0.20). Therefore plain bupivacaine 0.5%, isobaric at 20 degrees C, seems to get the properties of an hyperbaric solution when cooled at 5 degrees C.