[Influence of injection speed of the spread of 4.0 ml of 0.5% isobaric bupivacaine in spinal anesthesia].

Influence of injection speed on the spread of isobaric 0.5% bupivacaine 4.0 ml was studied in 100 patients to analyze the correlation between analgesia levels and patient's characteristics. All patients (ASA PS I.II) were scheduled for orthopedic or urological procedures, and received no premedication. They were randomly divided into two groups by injection speed; group 1 of 0.2 ml.sec-1 and group 2 of 0.03 ml.sec-1. Spinal tap was performed in lateral decubitus position at the L 3-4 intenspace with median approach, using a 25 G Quincke needle. Immediately after the injection, the patient was placed in supine position. The maximum sensory block was tested by pinprick method, and no significant difference in the height of sensory block was observed between the two groups. No significant correlation with patient's characteristics was observed except body weight in group 1. This study suggests that the speed of injection does not influence the spread of isobaric 0.5% bupivacaine 4.0 ml.