A comparative study of haemodynamic effects of single-blinded orotracheal intubations with intubating laryngeal mask airway, Macintosh and McGrath video laryngoscopes

Introduction
The efficacy of an intubation technique is crucial to the success of ventilation therapies. Intubating laryngeal mask airway (ILMA), Macintosh and McGrath techniques are yet to be evaluated thoroughly. Orotracheal intubations with ILMA, McGrath, and Macintosh laryngoscopes are compared based on haemodynamic changes, time taken for intubations, and success rate.

Material and methods
This is a prospective, single-blinded, randomised controlled trial. Primary outcome: identification of the most efficient intubation technique. Secondary outcomes: haemodynamic parameters, time taken for intubation and the rate of success of intubation. Patients enrolled: 90. Groups: 3. Each participant is randomly assigned to a group. Inclusion criteria: both sexes, age: 18–55 years, ASA: I or II, Mallampati < III, Mouth opening > 2 fingers, BMI < 40 kg m-2, any elective surgery, general anaesthesia requiring endotracheal intubation. The haemodynamic changes, time taken for intubations, and success rate during ILMA, Macintosh and McGrath intubations were recorded and statistically analysed.

Results
Macintosh and ILMA raised the heart rate (min-1) more than McGrath at the second minute (95% CI: 76.50 ± 1.34 [McGrath] < 81.73 ± 1.46 [Macintosh] < 90.42 ± 1.24 [ILMA]). ILMA required the longest intubation time (s) (95% CI: 71.64 ± 2.14 [ILMA] > 40.26 ± 1.36 [McGrath] > 30.63 ± 1.53 [Macintosh]). Macintosh and McGrath intubations were all successful, whereas ILMA recorded two failures. However, the observed failures were statistically insignificant (95% CI: 93.33 ± 4.35%).

Conclusions
McGrath intubation is the most efficient technique based on its haemodynamics. ILMA required the longest intubation time and statistically, rates of success of the techniques are alike.