[Is 0.5% bupivacaine solution isobaric?]

Bupivacaine 0.5% 3 ml was administered by subarachnoid injection to 100 patients. They were divided to four equal groups, according to the body position immediately following the injection: horizontal supine and lateral, sitting and Trendelenburg position. 15 min after the injection was the median dermatome in the later group at T 8.64, and after 60 min at T 7.44 level. The corresponding values for sitting patients were T 5.48 respect. T 3.08. It was concluded that subarachnoidally applied bupivacaine 0.5% shows hypobaric characteristics. This is in agreement with already reported in vitro determinations.