Haemodynamic response to tracheal intubation or laryngeal mask insertion in hypertensive patients

The haemodynamic response to laryngeal mask insertion and tracheal intubation was studied in 27 hypertensive patients who underwent elective ophthalmic surgery. Both groups received alfentanil 15 micrograms/kg, thiopentone 3-4 mg/kg and vecuronium 0.1 mg/kg and were ventilated with oxygen, nitrous oxide and isoflurane for 3 minutes prior to laryngeal mask insertion or tracheal intubation. Blood pressure and heart rate decreased equally in both groups after induction of anaesthesia. Haemodynamic variables increased after tracheal intubation but were unchanged after laryngeal mask insertion (P < 0.05 for intergroup differences). Heart rate, but not blood pressure, increased above baseline levels in the tracheal intubation group. The anaesthetic technique used blunted the haemodynamic response to tracheal intubation, but completely blocked the response to laryngeal mask insertion.