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Reversal of Fentanyl‐Induced Narcotic Depression with Naloxone Following General Anaesthesia
Author(s) -
Tigerstedt Irma
Publication year - 1978
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1978.tb01297.x
Subject(s) - medicine , fentanyl , anesthesia , (+) naloxone , normocapnia , narcotic , hypercapnia , morphine , ventilation (architecture) , opioid , mechanical engineering , acidosis , engineering , receptor
To study the need for and mode of naloxone reversal after liberal use of fentanyl during anaesthesia, a fixed‐dose schedule of fentanyl (mean 6.5 μg/kg/h) was applied intraoperatively to 60 patients, randomly divided into four treatment groups. After surgery and reversal of muscle relaxation, end‐tidal CO 2 was allowed to rise to 8% by manually assisted ventilation. Thereafter, 0.04 mg increments of naloxone were given i.v. every 3 min until spontaneous respiration maintained ET co2 below 8% (group I) or below 6.5% (group II). After similar intravenous reversal to that in groups I or II, an additional intramuscular dose of naloxone, identical to that given i.v., was given to groups III and IV after awakening from nitrous oxide. If ET co2 remained above 6.5%, mean spontaneous minute ventilation was lower than before anaesthesia and significantly (P<0.05) less than if ET co2 had decreased below that value. This difference had disappeared 45 min postnal‐oxone. Arterialized venous P co2 showed normocapnia (6.0 kPa) in patients with ET co2 <6.5%, hut slight hypercapnia (6.6 kPa) in patients with ET co2 >6.5% after intravenous naloxone. After 15 min, the patients with additional intramuscular naloxone had significantly ( P< 0.05) lower values of P co2 than those with intravenous naloxone only. Postoperatively, a positive correlation (R = 0.35) between the total dose of naloxone and pain intensity could be demonstrated (P<0.01). As acute postoperative pain could not be avoided after naloxone reversal to normoventilation, titration of naloxone after liberal use of analgesics is recommended with the help of capnography, until an acceptable ET co2 of about 7% is maintained.