Extradural fentanyl for postoperative analgesia: predominant spinal or systemic action?

• Published in: British journal of anaesthesia : BJA Vol. 74; no. 2; pp. 184 - 187
• Main Authors: COOPER, D.W., RYALL, D.M., DESIRA, W.R.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.1995; Oxford University Press
• Subjects: Adolescent; Adult; Anaesthetic techniques; Anaesthetic techniques, extradural; Analgesia; Analgesia, Epidural; Analgesia, Obstetrical; Analgesia, Patient-Controlled; Analgesics; Analgesics opioid; Analgesics opioid, fentanyl; Biological and medical sciences; Cesarean Section; Double-Blind Method; extradural; Female; fentanyl; Fentanyl - administration & dosage; Humans; Injections, Intravenous; Medical sciences; Neuropharmacology; Pain, Postoperative - prevention & control; patient-controlled; Pharmacology. Drug treatments; Pregnancy; Analgesics opioid, fentanyl; Analgesia, patient-controlled; Anaesthetic techniques, extradural; Human; Postoperative; Spinal cord; Intravenous administration; Opiates; Narcotic analgesic; Site of action; Analgesia; Chemotherapy; Pain; Treatment; Extradural administration; Comparative study
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/74.2.184

This randomized, double-blind study of 40 patients was designed to determine if the predominant analgesic effect of extradural fentanyl is mediated by a direct spinal action or an indirect systemic one. After Caesarean section, postoperative analgesia was provided for 24 h by patient-controlled extradural analgesia (PCEA group) or by patient-controlled i.v. analgesia (PCIVA group). Both groups received a bolus dose of fentanyl 20 μg with a 10-min lockout interval. In the PCIVA group, nine patients stopped early (compared with none in the PCEA group) because of inadequate analgesia. Mean visual analogue pain scores (0–100 mm) at 8 and 12 h were lower for PCEA (23 (SD 13) mm at rest, 31(23) mm on coughing) than for PCIVA (50 (25) mm at rest, 67 (24) mm on coughing) (P < 0.0005). The mean dose of fentanyl self-administered between 4 and 8 h was lower in the PCEA group (38 (So 30) μg h−1 compared with the PCIVA group (59 (27) μg h−1 (P < 0.05). Our results support the hypothesis that the predominant analgesic effect of extradural administration of fentanyl is mediated by a direct spinal action rather than an indirect action from systemic absorption.