Unpredictability of regression of analgesia during the continuous postoperative extradural infusion of bupivacaine.
Twenty-four otherwise healthy patients scheduled for elective major abdominal surgery received general anaesthesia plus lumbar extradural analgesia. A loading dose of 0.5% plain bupivacaine was given to produce sensory analgesia (pin prick) from T4 to S5 and followed by a continuous infusion of 0.5% plain bupivacaine 8 ml h-1. Pain, scored on a 5-point scale, and sensory analgesia were assessed hourly for 16 h after skin incision. If sensory analgesia decreased by more than 5 segments from its preoperative level, or if the pain score reached 2 (moderate pain), the patients were removed from the study, and pain was treated otherwise. Only three patients maintained their initial levels of sensory analgesia and a pain score of less than 2. In the remaining patients sensory analgesia decreased at least 5 segments or pain score reached 2 between 4 and 16 h after skin incision. We found a weak correlation between increasing age and the duration of sensory analgesia (r = 0.46, P less than 0.05), but no significant correlations between duration of sensory analgesia and sex, weight, height, body surface area, serum albumin concentration, duration or site of operation.
Mogensen
T
T
Department of Anaesthesia, Hvidovre Hospital, Copenhagen, Denmark.
Hjortsø
N C
NC
Bigler
D
D
Lund
C
C
Kehlet
H
H
D000005:Abdomen / Q000601:surgery; D000767:Anesthesia, Epidural; D000768:Anesthesia, General; D002045:Bupivacaine / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007263:Infusions, Parenteral; D008297:Male; D010149:Postoperative Pain / Q000517:prevention & control*; D013997:Time Factors
D002045:Bupivacaine