The intubating laryngeal mask produces less heart rate response to intubation than conventional laryngoscopy

We compared heart rate and blood pressure changes to intubation produced by conventional laryngoscopic-guided intubation to those produced by blind intubation through the intubating laryngeal mask (ILM) in normotensive adults with normal airways. Forty paralysed, anaesthetised adults undergoing elective surgery were randomly assigned to one of two groups: 1. Blind intubation through the ILM using a straight silicone tracheal tube manufactured for specific use with the ILM; 2. Intubation with a size 3 macintosh laryngoscope using a polyvinyl chloride tube. Intubation success rate, number of intubation attempts, time to intubation were recorded. Heart rate and non-invasive blood pressure preinduction, preintubation and at one minute intervals after intubation until ten minutes post intubation were recorded. The intubation success rate was 90%(68% first attempt)for the ILM group and 100%(all first attempt) for the laryngoscopic group. Time to successful intubation was longer (50 vs 22s) and more intubation attempts were required in the ILM group (p<0.0001). Changes from pre-intubation values showed a significantly lower heart rate response in the ILM group at 4 to 10 minutes post intubation (p<0.05). The ILM may have a role in managing the intubation response in patients where an increase in heart rate is associated with an increased risk, such as in patients with ischaemic heart disease.