title: The role of halothane and fentanyl in the production of balanced anaesthesia.
abstract: The aim of the study was to quantitate the degree of respiratory depression when tolerance of superficial nociception and of an endotracheal tube was achieved by supplementing N2O + O2 anaesthesia either with halothane alone or with halothane in combination with fentanyl. Eighty-four patients, matched into seven groups, were studied after induction of anaesthesia with thiopental (4 mg/kg) and suxamethonium (3 mg/kg) using the following supplementation: 0.8, 0.6, 0.4% halothane alone or 0.4, 0.2, 0% halothane with 0.5-2 micrograms/kg fentanyl. After 10 min administration of the anaesthetic mixture using manual intermittent positive pressure ventilation (IPPV) (end-tidal CO2 c. 5.5%), IPPV was discontinued and spontaneous respiration allowed to return. When the end-tidal CO2 had stabilized, samples for blood gas analysis were taken and superficial antinociception was tested by pinching an inguinal skin fold. Supplementation of an N2O + O2 mixture with 0.8% halothane without fentanyl or with 0.4% halothane with 0.5 microgram/kg fentanyl seemed to come closest to the optimum in producing tolerance of an endotracheal tube and of superficial nociception (in about 85% of cases with an increase in PCO2 to only 7 kPa.
mesh_terms: D000328:Adult; D000758:Anesthesia; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood; D005283:Fentanyl; D006221:Halothane; D006801:Humans; D007385:Intermittent Positive-Pressure Ventilation; D007442:Intubation, Intratracheal; D009609:Nitrous Oxide; D012119:Respiration / Q000187:drug effects
chemical_list: D002245:Carbon Dioxide; D009609:Nitrous Oxide; D005283:Fentanyl; D006221:Halothane