A comparison of the Laryngeal Tube S and the LMA ProSeal laryngeal mask airway

Abstract

I was interested to see the paper by Dr Klaver and colleagues comparing novice anaesthetists' performance with the LMA ProSeal® (PLMA, Intavent Orthofix, Maidenhead, UK) and Laryngeal Tube-S (LTS, VBM GmbH, Sulz, Germany) [1]. Unfortunately, much of the data in the paper are redundant as the LTS was withdrawn by the manufacturers in 2005 when it was superseded by the LTS mark II (LTS II, VBM GmbH). There are marked physical and performance differences between the devices. Amongst the changes are that the LTS II is considerably longer and the distal tip and cuff are both reshaped to improve anatomical fit (Fig. 1). There are also minor changes to the airway orifices and to the pilot balloon. The Laryngeal Tube Suction (LTS) (bottom) and Laryngeal Tube Suction mark II (LTS II) (above). Prior to the change of design there were four papers comparing the PLMA and LTS, with three reporting very similar performance [2–5] and one reporting markedly better performance by the PLMA [6]. The decision to redesign the LTS was made because of feedback to the manufacturers from users of the original device (F. Haegele, VBM GmbH, personal communication). We have recently completed an evaluation of the LTS II and found considerably better performance than our previous evaluations of the LTS [6]. In particular, insertion was easier and more successful, axial stability was improved and ventilation failures were less frequent. Insertion performance of the LTS by novices is an important issue as laryngeal tubes were originally designed for airway rescue and for use outside hospital; however, the performance of the LTS is unlikely to be the same as that of the LTS II, which is already showing promise in this field [7]. More work comparing the performance of the LTS II with alternative supraglottic airway devices that offer protection against aspiration (such as the PLMA, i-gel (Intersurgical, Wokingham, UK), LMA-Supreme (Intavent Orthofix) and perhaps the SLIPA (Hudson RCI, Ashby-de-la-Zouch, UK) is to be welcomed, and some work has already been performed [8]. Sadly, however, Dr Klaver and colleagues' article offers no useful new information as it evaluated a device that is now not available and the performance of which cannot be assumed to be similar to its successor. Publication of such papers adds little except to increase confusion surrounding the topic. Dr Cook has been paid for lecturing by the LMA Company and Intavent Orthofix, both of which produce LMA ProSeal laryngeal mask airways. He has received free equipment from VBM GmbH (and also from other medical manufacturers) for research and evaluation.