Comparison of the I-gel supraglottic airway as a conduit for tracheal intubation with the intubating laryngeal mask airway

Abstract

We read with concern the recent article of Michalek et al.1Michalek P. Donaldson W. Graham C. Hinds J.D. A comparison of the I-gel supraglottic airway as a conduit for tracheal intubation with the intubating laryngeal mask airway: a manikin study.Resuscitation. 2010; 81: 74-77Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar comparing the I-gel supraglottic airway (I-gel) and intubating laryngeal mask airway (ILMA) as conduits for tracheal intubation in a manikin study. The results of this study suggest that fibreoptic intubation through both ILMA and I-gel is a highly successful technique. However, there are several design aspects that have to be clarified. In fact, this study only completely assessed the blind intubation through both ILMA and I-gel. Whereas the other groups only observed the blind tracheal placement of the gum-elastic bougie and Aintree intubating catheter (AIC) and tracheal insertion of fibreoptic bronchoscope (FOB), because railroading of the tracheal tube over these guide devices through the ILMA and I-gel was omitted. Although prior studies have documented the clinical efficacy of AIC, gum-elastic bougie and FOB guided intubations,2Blair E.J. Mihai R. Cook T.M. Tracheal intubation via the Classic™ and Proseal™ laryngeal mask airways: a manikin study using the Aintree Intubating Catheter.Anaesthesia. 2007; 62: 385-387Crossref PubMed Scopus (33) Google Scholar, 3Latto I.P. Stacey M. Mecklenburgh J. Vaughan R.S. Survey of the use of the gum elastic bougie in clinical practice.Anaesthesia. 2002; 57: 379-384Crossref PubMed Scopus (86) Google Scholar, 4Joo H.S. Rose D.K. The intubating laryngeal mask with and without fibreoptic guidance.Anesth Analg. 1999; 88: 662-666Crossref PubMed Google Scholar failed intubation with the guide device through the supraglottic airway device (SAD) may indeed occur in some occasions, particularly at the first attempt.5Danha R.F. Thompson J.L. Popat M.T. Pandit J.J. Comparison of fibreoptic-guided orotracheal intubation through classic and single-use laryngeal mask airways.Anaesthesia. 2005; 60: 184-188Crossref PubMed Scopus (39) Google Scholar Also, there is no study to compare the efficacy of AIC, gum-elastic bougie and FOB guided intubations through the SAD. Therefore, it would have been perhaps more informative to provide and compare the data regarding the AIC, gum-elastic bougie and FOB guided intubations through both ILMA and I-gel, such as successful intubation, resistance to advance tracheal tube over the guide devices, oesophageal intubation and intubation time, as performed in previous studies.5Danha R.F. Thompson J.L. Popat M.T. Pandit J.J. Comparison of fibreoptic-guided orotracheal intubation through classic and single-use laryngeal mask airways.Anaesthesia. 2005; 60: 184-188Crossref PubMed Scopus (39) Google Scholar, 6Hodzovic I. Petterson J. Wilkes A.R. Latto I.P. Fibreoptic intubation using three airway conduits in a manikin: the effect of operator experience.Anaesthesia. 2007; 62: 591-597Crossref PubMed Scopus (12) Google Scholar, 7Sreevathsa S. Nathan P.L. John B. Danha R.F. Mendonca C. Comparison of fibreoptic-guided intubation through ILMA versus intubation through LMA-CTrach.Anaesthesia. 2008; 63: 734-737Crossref PubMed Scopus (14) Google Scholar Based on the findings of this study, we believe it would be more appropriate to conclude that the tracheal placement of FOB through both ILMA and I-gel is a highly successful technique. Except for the ILMA designed for the tracheal intubation, the lengths of an appropriate endotracheal tube (ETT) and a SAD (including I-gel) are almost similar. Once the ETT is inserted into the trachea through a SAD, proximal end of the ETT tends to disappear into the airway tube of a SAD. When the tracheal intubation is performed through a SAD, therefore, the greatest challenge is how to remove the SAD after successful intubation, without dislodging the ETT from the trachea.8Xue F.S. Luo M.P. Liao X. Tang G.Z. Measures to facilitate the classic laryngeal mask airway guided fiberoptic intubation in children with a difficult airway.Paediatr Anaesth. 2008; 18: 1273-1275Crossref PubMed Scopus (16) Google Scholar In managing difficult airway, dislodgement of the ETT from the trachea during removal of the SAD not only can result in the failed intubation, but also may put the patient at a risk of loss of airway control. To provide the further safety data of the tracheal intubations through the ILMA and I-gel, the authors should assess and compare the removal of the two devices after successful intubation. This study was performed in the manikins with a normal airway, rather than in a standardized difficult airway manikin scenario. The authors argued that in a recent study, the I-gel performed well in simulated difficult airway situations.9Theiler L.G. Kleine-Brueggeney M. Kaiser D. et al.Crossover comparison of the laryngeal mask supreme and the i-gel in simulated difficult airway scenario in anesthetized patients.Anesthesiology. 2009; 111: 55-62Crossref PubMed Scopus (123) Google Scholar In patients wearing a neck collar and with cricoid pressure applied in a simulated trauma scenario, however, the ILMA is difficult to insert and ventilation is difficult in a proportion of patients.10Wakeling H.G. Nightingale J. The intubating laryngeal mask airway does not facilitate tracheal intubation in the presence of a neck collar in simulated trauma.Br J Anaesth. 2000; 84: 254-256Crossref PubMed Scopus (51) Google Scholar Also, the FOB-guided intubation through the ILMA seems to be more difficult in a difficult airway than in a normal airway.11Asai T. Eguchi Y. Murao K. Niitsu T. Shingu K. Intubating laryngeal mask for fibreoptic intubation-particularly useful during neck stabilization.Can J Anaesth. 2000; 47: 843-848Crossref PubMed Scopus (30) Google Scholar In patients, moreover, fibreoptic endoscopy can be difficult because of airway trauma, bleeding, secretions and fogging of the lenses. All these factors cannot be replicated in a manikin. For this reason, it must be cautious to extrapolate their results to the patients with a difficult airway. All authors have no financial support and potential conflicts of interest for this work.