Cardiovascular responses following laryngoscope assisted, fibreoptic orotracheal intubation

The Macintosh laryngoscope has recently been used successfully as an airway clearance device during fibreoptic intubation in patients who presented difficult intubation, but it is not known whether this approach will increase the pressor response to intubation. The aim of this investigation was to compare the cardiovascular responses of this method of facilitating airway clearance with the lingual traction plus jaw thrust method. 40 ASA I or II adult patients were given a standardised general anaesthetic and were randomly allocated to receive either lingual traction with jaw thrust (lingual traction group) or direct laryngoscopy with a Macintosh laryngoscope (laryngoscopy group) as the airway clearance manoeuvre prior to fibreoptic orotracheal intubation. Following intubation there was a significant rise in arterial pressure above pre-induction levels in both groups (p < 0.05); however, the arterial pressure in the laryngoscopy group was significantly greater than that in the lingual traction group (systolic: p = 0.031, diastolic: p = 0.002). It appears therefore that the mechanical stimulus of the Macintosh laryngoscopy evokes a greater pressor response than that of lingual traction plus jaw thrust when these interventions are followed by fibreoptic intubation.