Changes in Skin Temperature and Sensory Blockade during Spinal Anesthesia

Kim, Heung Dae; Song, Sun Ok

Abstract

Twenty otherwise healthy patients, scheduled for elective operations below the knee joints, were allocated to spinal anesthesia with 2 ml 0.5% hyperbaric tetracaine or 2.5 ml 0.5% plain bupivacaine. The levels of sensory blockade(analgesia level to pinprick test) and sympathetic blockade(cephalad level of skin temperature elevation with electronic thermometer) were measured at 5, 10, 20, 30, 60, 90, and l20 minutes after injection of the local anesthetics. The results were as follows: 1) The two groups were well matched for age, height and weight. 2) The decrease in systolic pressure was insignificantly more pronounced in the tetracaine group, and heart rate fell slightly and similarly in both groups. 3) In both groups, the uppermost levels of sensory blockade were T(6~7) about 20 minutes after injection, and their levels were decreased from 30 minutes after injection. 4) In both groups, the uppermost levels of skin temperature elevation were T(5~7) about 20 minutes, insignificantly higher in the tetracaine group, and their levels were decreased from 30 minutes after injection. 5) In both groups, the levels of skin temperature elevation were 1-2 segment higher than those of sensory blockade during onset about 20 minutes, similar at 30 minutes, and lower than those of sensory blockade after l hour following injection,of the local anesthetics. The conclusion of this study is that during spinal anesthesia the relation of the levels of sympathetic and sensory blockade is no difference between induced anesthetic agents, and the time interval following intrathecal injection is important factor in their relationship.