Pulmonary aspiration associated with supraglottic airways: Proseal laryngeal mask airway and I-Gel™

Corresponding author: Yoon-Hee Kim, M.D., Ph.D., Department of Anesthesiology and Pain Medicine, Chungnam National University School of Medicine, Munhwa-ro, Jung-gu, Daejeon 301-721, Korea. Tel: 82-42-280-7840, Fax: 82-42-280-7968, E-mail: [email protected] This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. CC Supraglottic airways (SGAs) are increasingly used by SGA friendly users in patients who are traditionally assumed to be at an increased risk for aspiration. For instance, at first, its use was controversial, its airtight seal and the absence of gastric aspiration with the supraglottic airway during laparoscopic surgery was shown throughout “conventional” positive ventilation [1,2]. The evidence to date suggests that pulmonary aspiration associated with the supraglottic airway is rare and has an incidence comparable to that of outpatient anesthesia with the face mask and endotracheal tube [3]. However, in principal, supra glottic airways do not prevent gastric aspiration as reliably as tracheal intubaton does. The insertion of the SGA has been reported to increase the esophageal motility and to reduce the lower esophageal sphincter barrier pressure. A possible mechanism for this situation is that the distension of pharynx induced by large inflated cuff of the SGA trigger the pharyngo-esophago-gastric reflex [4]. When conscious, this reflex will facilitate swallowing. SGA with features, such as airtight sealing, separate access to the gastrointestinal and respiratory tracts and esophageal drainage tube improve the safety and efficacy of positive pressure ventilation, provide a means of gastric suctioning, reduce the gastric distension, and the risk of pulmonary aspiration. There are now several supraglottic airways marketed that are specifically designed to reduce the risk of aspiration. Five devices are designed to separate the respiratory and gastrointestinal tracts: the I-Gel (Intersurgical Ltd, Wokingham, Berkshire, UK), laryngeal tube suction mark II (LTS II) and its disposable version (LTS-D) (VBM GmbH, Sulz, Germany), the proseal laryngeal mask airway, the recently introduced laryngeal mask airway Supreme (Intavent Orthofix, Maidenhead, UK), and the streamlined liner of the pharyngeal airway (Teleflex Medical, High Wycombe, UK, SLIPA). The device SLIPA is designed to prevent aspiration through its large hollow chamber that can store up to 50 ml of regurgitant gastric fluid [5]. In this edition of Korean Journal of Anesthesiology, Jeon et al. [6] presented a clinical study on 30 patients undergoing laparoscopic gynecologic surgery with either a Proseal laryngeal mask airway or an I-Gel to secure the airway. The study showed that there was no significant difference in the leak fraction between the two airways. The authors concluded that I-Gel is a reasonable alternative to the Proseal laryngeal mask airway for controlled ventilation during laparoscopic gynecological surgery. Proseal laryngeal mask airway and I-Gel are second generation SGA that has high esophageal sealing pressure and esophageal drainage tube, effective in preventing gastric aspiration. The use of the Proseal laryngeal mask airway since been reported in a number of clinical situations, including elective laparoscopic surgery and even in patients ventilated in the prone position [7,8]. In addition to the use for planned anesthesia, current guidelines also recommend Proseal laryngeal mask airway as an alternative to tracheal intubation during cardiopulmonary resuscitation [9]. In a fresh cadaver model, where the esophagus was filled with fluid increase pressure, Proseal laryngeal mask airway showed complete protection during esophageal regurgitation when esophageal drainage tube was patent [10].