Blocking the circulatory responses to tracheal intubation: a comparison of fentanyl and nalbuphine

The effects of three drug administration programmes on the haemodynamic responses to tracheal intubation have been compared. Thirty patients received thiopentone 4 mg/kg. Ninety seconds later, following the injection of either saline, nalbuphine 0.3 mg/kg or fentanyl 5 micrograms/kg, suxamethonium 1.5 mg/kg was given. The pressor response to tracheal intubation which occurred after saline was reduced after nalbuphine (p less than 0.05) but a tachycardia still occurred. In contrast, neither an increase in blood pressure nor heart rate occurred in those patients given fentanyl. It is concluded that nalbuphine 0.3 mg/kg is only partially effective in reducing the cardiovascular responses to laryngoscopy and tracheal intubation.