Comparison of Laryngeal tube suction II (LTS II) and Proseal laryngeal mask airway (PLMA) for controlled ventilation in anaesthetised and paralysed adult patients

Background: LTS II and PLMA are supraglottic devices that may be used for ventilation in patients with normal as well as difficult airways at risk of aspiration. Aim: Comparison of LTS II with PLMA during controlled ventilation in paralysed patients with respect to time to successful insertion, success rate of insertion, attempts at repositioning, airway leak pressure, ease of ventilation and Ryle’s tube insertion, fibreoptic laryngeal view and complications. Methods: Thirty patients were studied using a prospective, randomised cross-over design. Ethical committee clearance and informed consent were obtained from all patients. Anaesthesia was induced with propofol and fentanyl and neuromuscular blockade achieved with vecuronium. Patients were divided into two groups: Group LTS and Group PLMA. In each group, the first airway device was inserted, various parameters observed and then removed. The second airway device was then inserted and the same parameters noted. Anaesthesia was continued with the second device in position. Results: Success with insertion at first attempt and time to insertion were comparable with both devices [LTS II 27/30 (17.5 s) and PLMA 29/30 (15.5 s) respectively]. PLMA required repositioning in fewer patients and provided better fibreoptic view than LTS II. Ryle’s tube insertion failed in four patients with PLMA but in none with LTS II. No significant difference was found in the airway seal pressure [mean, PLMA (27 cm H2 O) and LTS II (26.4 cm H2 O)], ease of ventilation or overall complications. Conclusion: Insertion and ventilation are comparable with PLMA and LTS II. Ryle’s tube insertion is easier with LTS II but requires more repositioning attempts and does not provide a good view of the larynx