To compare clinical versus ultrasound assessment of correct placement of ProSeal Laryngeal mask airway (PLMA): a prospective randomized study

Abstract

Extraglottic airway devices (EAD) have revolutionized the perioperative airway management. The accuracy of clinical tests to identify malposition has been questioned by recent studies where fibreoptic evaluation identified various malpositions that were undiagnosed by a clinical test. Ultrasound (USG) has evolved to guide various airway interventions. However, USG is under-evaluated in the assessment of the EADs position. Our study aimed to compare clinical versus USG assessment of optimal placement of ProSeal laryngeal mask airway (PLMA). This randomized control trial was done in 212 consenting patients undergoing onco-surgery with PLMA as an airway device. Patients were randomized in Group CL (n-107) and US (n-105). Following primary assessment-using clinical tests and USG evaluation using a scoring system, fibreoptic evaluation of the placement of PLMA was done and then assessed for optimal position. The accuracy of each technique for optimal placement was compared statistically. We found that the sensitivity and specificity of the clinical evaluation were 98.77% and 34.62% with a diagnostic accuracy of 83.18% when compared with fibreoptic evaluation. While USG evaluation using the scoring system has sensitivity and specificity of 95.45% and 29.41% with a diagnostic accuracy of 84.76%. It was noted that USG assessment has a higher positive predictive value (87.5%) as compared to clinical assessment (82.47%). The incidence of rotation was higher in the clinical group. There was no difference in airway related morbidity. USG is comparable to clinical tests for evaluation of the optimal placement of PLMA. However, USG has various advantages over clinical assessment as it is quick and identifies the unacceptable placement of PLMA where the tip of PLMA may not lie over the tip of the esophagus, thereby, avoiding unnecessary mucosal injury during forceful or repeated attempts for gastric drainage tube insertion.Trial registration: Clinical Trials Registry (CTRI/2017/11/010359) dated 3rd November 2017.