Are there predictive tests that determine the difficulty in Laryngeal Mask Airway Insertion?

Objective: To determine the predictive tests for difficulty in laryngeal mask airway insertion, and to observe the success rate of insertion in the first attempt.

Methods: The prospective, observational study was conducted at Bülent Ecevit University Hospital, Turkey, from September 2013 to 2014, and comprised patients of American Society of Anaesthesiologists grade I to IV adult patients who underwent elective surgery under general anaesthesia. The supraglottic airway device was randomly selected for each patient, and the laryngeal mask airway was used as per the decision of an anaesthesiologist who was not part of the study. Patients were divided into three groups according to laryngeal mask airway types as classic group A, i-gel group B and suprema group C. These were inserted by anaesthesia residents with the same seniority when bispectral index value reached 40-60. Data was noted and analysed using SPSS 24.

Results: Of the 120 patients, 40(33.33%) were in cLMA, 38(31.66%) in i-gel, and 42(35%) in sLMA. There was no significant difference among the groups in terms of demographics (p>0.05). Apart from the height/thyromental distance ratio (p=0.046), no predictive test was statistically significant in identifying the difficulty in laryngeal mask airway insertion (p>0.05). There was no significant difference involving number of attempts, difficulty in insertion, and patient response (p>0.05). Placement success rate at first attempt was similar among the groups (p>0.05).

Conclusions: Higher height/thyromental distance ratio values were associated with difficulty in laryngeal mask airway insertion, and first-attempt success rate was similar in all the three laryngeal mask airway types.