Intrathecal morphine during thoracotomy, Part I: Effect on intraoperative enflurane requirements.
The ability of intrathecal morphine to reduce the anesthetic requirements during thoracotomy was investigated. Twenty-four patients scheduled for thoracic surgery were studied. Anesthesia was induced with thiamylal sodium, 4 mg/kg, fentanyl, 100 micrograms, and 100 mg of succinylcholine. Prior to skin incision, 12 patients received intrathecal injection of 12 micrograms/kg of preservative-free morphine sulfate (ITM), while the remaining 12 patients served as controls. The ITM was given undiluted at the L3-4 or L4-5 level. Anesthesia was maintained solely with enflurane, titrated to keep mean arterial pressure within 15% of the preoperative values. Vecuronium was given as required for relaxation. No additional narcotics were administered. Throughout the procedure, end-tidal (ET) enflurane concentration was recorded at 15-minute intervals from the mass spectrometer (Perkin Elmer). The intraoperative mean ET concentration of enflurane was significantly reduced in the ITM group beginning 1 hour after the injection (1.19 +/- .45% in the control group versus 0.73 +/- 0.08% in the ITM group). The enflurane requirements, expressed as percent end-tidal enflurane/hour, were significantly less in the ITM group for the duration of the procedure (0.8 +/- .17 v 1.08 +/- .22, respectively). In conclusion, when administered prior to skin incision for post-thoracotomy pain control, intrathecal morphine reduces intraoperative enflurane requirements.
Cohen
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Department of Anesthesiology, Mount Sinai Medical Center, New York, NY 10029-6574.
Neustein
S M
SM
D000368:Aged; D000769:Anesthesia, Inhalation; D004347:Drug Interactions; D004737:Enflurane / Q000008:administration & dosage* / Q000378:metabolism; D006801:Humans; D007278:Injections, Spinal; D007430:Intraoperative Care; D008168:Lung; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use*; D010149:Postoperative Pain / Q000517:prevention & control*; D012121:Respiration, Artificial; D013908:Thoracotomy / Q000009:adverse effects; D013990:Tidal Volume; D013997:Time Factors
D009020:Morphine; D004737:Enflurane