Abstract

The ProSeal laryngeal mask airway (PLMA) has become an essential supraglottic airway device in modern anesthetic practice, yet predicting insertion difficulty remains a clinical challenge that can impact patient safety and operating room efficiency. This prospective observational study aimed to evaluate the predictive accuracy of various pre-operative bedside airway assessment tests for determining ease of PLMA insertion in adult patients undergoing elective surgery. A total of 280 patients aged 18-70 years, ASA physical status I-III, scheduled for elective procedures under general anesthesia with planned PLMA insertion were enrolled between January 2022 and December 2023. Pre-operative airway assessment included systematic evaluation of Mallampati classification, thyromental distance, sternomental distance, mouth opening, neck circumference, upper lip bite test, neck extension, and mandibular protrusion test. The primary outcome was ease of PLMA insertion categorized as easy (successful insertion within first 2 attempts), moderately difficult (3-4 attempts), or difficult (>4 attempts or failure requiring alternative airway). Secondary outcomes included insertion time, seal pressure, and complications. Easy insertion was achieved in 198 patients (70.7%), moderately difficult in 58 patients (20.7%), and difficult insertion in 24 patients (8.6%). Multivariate analysis identified Mallampati class III-IV (OR 5.2, 95% CI: 2.8-9.7, p<0.001), thyromental distance <6.5 cm (OR 4.1, 95% CI: 2.2-7.6, p<0.001), mouth opening <4 cm (OR 3.4, 95% CI: 1.8-6.4, p<0.01), neck circumference >42 cm (OR 2.8, 95% CI: 1.5-5.2, p<0.01), and upper lip bite test class III (OR 3.7, 95% CI: 1.9-7.1, p<0.001) as independent predictors of difficult insertion. A composite scoring system incorporating these five parameters achieved 84.2% sensitivity and 91.3% specificity for predicting difficult PLMA insertion, with area under the curve of 0.93. Multiple pre-operative bedside airway assessment tests can effectively predict PLMA insertion difficulty, with the strongest predictors being Mallampati classification, thyromental distance, and mouth opening. The developed composite scoring system provides a practical clinical tool for risk stratification, enabling anesthesiologists to anticipate insertion challenges and optimize perioperative airway management strategies.