Quantitative sensory examination of epidural anaesthesia and analgesia in man; dose-response effect of bupivacaine.
Time and dose-response functions of 4 concentrations of epidural bupivacaine (0.075, 0.125, 0.25, and 0.5%; 20 ml) on somatosensory and motor functions were examined in 10 healthy volunteers. Every hour for 8 h the effect of epidural bupivacaine on perception of painful and non-painful stimuli was quantified with 12 psychophysical measures. In addition knee extension strength, reaction time and skin temperature were examined. The two lowest concentrations of bupivacaine induced hypoalgesia without impairment of motor function. Epidural bupivacaine produced differential blockade of non-painful somatosensory functions in the following order: warmth perception > cold perception > perception of electrical stimuli. Epidural bupivacaine induced more pronounced hypoalgesia for short-lasting than for prolonged stimuli. A modality-related blocking order was observed for prolonged painful stimuli: heat > mechanical > electrical. It is suggested that differential blockade of somatosensory functions is caused by differences both in conduction blockade of nerve fibres and in central integration of afferent nerve impulses.
Brennum
Jannick
J
Laboratory of Sensory Physiology, Department of Neurology, Gentofte Hospital, DK-2900 HellerupDenmark Department of Anaesthesia, Rigshospitalet, DK-2100 København ØDenmark Department of Medical Informatics, Aalborg University, DK-9100 AalborgDenmark.
Nielsen
Pernille T
PT
Horn
Allan
A
Arendt-Nielsen
Lars
L
Secher
Niels H
NH
D000328:Adult; D015360:Analgesia, Epidural; D000767:Anesthesia, Epidural; D002045:Bupivacaine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004558:Electric Stimulation; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007537:Isometric Contraction / Q000187:drug effects; D007834:Lasers; D008297:Male; D010146:Pain / Q000188:drug therapy* / Q000523:psychology; D017288:Pain Threshold / Q000187:drug effects; D010812:Physical Stimulation; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D012881:Skin Temperature / Q000187:drug effects
D002045:Bupivacaine