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Laryngeal mask airway during percutaneous dilatational tracheostomy
- Ulf Linstedt (1 February 2008)
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Intubating laryngeal mask (ILMA) as a ventilatory device
- Peter V Dimitrov, Chandy Verghese (22 January 2008)
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Use of the ProSeal LMA during percutaneous dilatational tracheostomy
- George M Haslam, Stephen R Laver, Jerry P Nolan, Kim Gupta, Tim M Cook (10 January 2008)
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Ulf Linstedt Diako Hospital Flensburg
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Editor, we would like to thank Dr. Dimitrov and Dr. Verghese as well as Dr. Haslam et al. for their letters in response to our article. We are delighted and encouraged to hear about the use of the LMA by such experienced teams. Colleagues who routinely use an endotracheal tube (ETT) during percutaneous dilatational tracheostomy (PDT) can be difficult to convince of the advantages and benefits of Laryngeal Mask Airways. Firstly, we would like to respond to Dimitrov and Verghese's first and third questions. In our study the change over from the ETT to an Intubating Laryngeal Mask (ILM) was performed just before the tracheostomy. To do this, the ILM was inserted behind the endotracheal tube (ETT) in situ, immediately followed by removing the ETT and then connecting the ILM to the ventilator. The question as to when after PDT lowest oxygen saturation (SaO2) occurs is, clearly, judged differently. We observed a very rapid recovery of oxygenation after connecting the ventilator to the tracheostomy tube. Therefore, we considered SaO2 values taken one minute after the surgery to be particularly meaningful. The second question from Dimitrov and Verghese, as well as the comment by Haslam et al., refers to the same issue. Which is the best LMA for PDT? Obviously, different authors prefer different types of Laryngeal Mask Airways and achieved good results with them. When planning our proposed study to compare LMA and ETT, we chose neither the ILM nor the ProSeal-LMA, but the LMA-classic. The ILM appears not to be the ideal LMA, because in our study breathing difficulties occurred in 21% of cases, (n=18), all of which were related to incorrect positioning of the ILM. In these cases, the ILM was not situated above the larynx (verified by bronchoscopy). Despite carrying out manipulations similar to the “Chandy- manoeuvre”, with four patients, sufficient ventilation could not be established. In trials with LMA-classic we achieved better results: in all cases, a correct positioning above the glottis was verified by bronchoscopy. The advantages of the ProSeal-LMA, described by Haslam et al., are easy to understand; clearly it is a suitable airway during PDT. Nevertheless, we do not use ProSeal-LMA for two reasons: 1. The risk of aspiration seems to be not as high as Haslam et al. presumed. It has never occurred in any of the more than 250 procedures in our institutions. (Routine procedures before PDT include abstaining from feeding for six hours and suctioning before removing the gastric tube). 2. The main advantage for us, in using the LMA-Classic, is that its lumen is much larger than that of the ProSeal-LMA. As a result, there is substantially less airway resistance with the bronchoscope inside. Our study comparing ETT with LMA (LMA-classic) has been completed. However, discussion about the different types of airway management continues ("none are a panacea" (Haslam)). Therefore, we would suggest a randomized study, which would focus solely on comparing the different types of LMAs during PDT. Literature: U. Linstedt, F. Möller, N. Grote, M. Zenz, and A. Prengel Intubating laryngeal mask as a ventilatory device during percutaneous dilatational tracheostomy: a descriptive study Br. J. Anaesth. 2007; 99: 912-915 Conflict of Interest:None declared |
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Peter V Dimitrov , Chandy Verghese
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Editor – We read with interest the article by Linstedt et al (1). We entirely agree with the authors’ conclusions and support their findings. We would like to add the following comments based on our experience of the technique (2). Firstly, the authors do not make it clear whether the endotracheal tube was completely removed at the beginning of the procedure. In our series the endotracheal tube (ETT) was electively removed at the start of the procedure following the insertion of the ILMA, behind the ETT; i.e. the ILMA was the ventilatory device for the PDT. It also allowed the passage of a fibreoptic laryngoscope (FOL) without interruption of ventilation during the PDT. Secondly, the initial leakage and subsequent reduction in minute ventilation can be reduced by optimising the position of the ILMA using the Chandy manoeuvre: the metallic handle of the ILMA can be used to lift the device in the direction used for direct laryngoscopy. We found this manoeuvre useful, though a bit uncomfortable for the user, in patients requiring high PEEP. Finally, we question the use of oxygen saturation at one minute as the end point for PDT. We consider this to be too early to judge that the procedure has been successful, and would suggest five minutes as a more appropriate end point, as per the ILMA group in this paper. The ILMA is a unique device that allows complete control of the airway in patients for PDT in the Intensive Care Unit. It allows easy control of the airway; a conduit for rapid re-insertion of an ETT either blindly, or using the fibreoptic scope if required; and the continuous application of PEEP using the Chandy manoeuvre. We agree with Linstedt et al that a randomised trial is needed to confirm the benefits of the ILMA in PDT. References: 1. Intubating laryngeal mask as a ventilatory device during percutaneous dilatational tracheostomy: a descriptive study. Linstedt U, Möller F, Grote N, Zenz M, Prengel A. British Journal of Anaesthesia. 2007; 99 (6): 912-915. 2. Airway control during percutaneous dilatational tracheostomy: pilot study with the intubating laryngeal mask airway. Verghese C, Rangasami J, Kapila A, Parke T. British Journal of Anaesthesia. 1998; 81: 608-609. Conflict of Interest:None declared |
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George M Haslam , Stephen R Laver, Jerry P Nolan, Kim Gupta, Tim M Cook
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Dear Editor – we read with interest the study by Linstedt and colleagues describing their experience of the intubating laryngeal mask airway (ILMA, Intavent-Orthofix, Maidenhead, United Kingdom) as a ventilatory device during percutaneous dilatational tracheostomy (PDT)1. Their conclusion that the ILMA can be recommended as a standard device for ventilation during bronchoscope-guided PDT and that a prospective randomised trial of ILMA and tracheal tube (TT) for PDT should be considered is to be welcomed. However, our accumulated experience of using the ProSeal Laryngeal mask airway (PLMA, Intavent Orthofix,) during PDT would suggest the need for a study arm examining the use of the PLMA during PDT. While several different supraglottic airway devices have been advocated for this procedure2,3, we believe the PLMA has several features that make its use close to optimal. The main potential benefit of a supraglottic airway device (SAD) instead of a TT to manage the airway during PDT is that bronchoscopy can include the whole of the trachea enabling correct identification of the site and level of tracheal puncture, which is not possible when a TT is in place. Use of the PLMA eliminates the risk of damaging a tracheal tube cuff and ‘spearing’ a Murphy eye, and reduces considerably the risk of puncturing the bronchoscope. In selecting the ideal SAD for this role in patients with ‘at risk lungs’ various features of the device are desirable including easy insertion, reliable ventilation even in patients with reduced pulmonary compliance (and with a bronchoscope placed within the device tube), easy access to the larynx with a bronchoscope and protection from the consequences of regurgitation and aspiration. Several features of the PLMA favour its use over the ILMA for PDT. The ILMA is the laryngeal mask least likely to sit directly over the glottis4 , whereas the PLMA, like the LMA-classic (cLMA), sits over the glottis in more than 90% of insertions5. The greater capacity of the PLMA bowl and absence of aperture bars (compared to the cLMA) or an epiglottic elevator (compared to the ILMA) is likely to make it easier to access the larynx. Unlike the ILMA, the PLMA is designed to minimise the risk of gastric distension, regurgitation and aspiration during use, and considerable evidence supports these goals5. Perhaps the only caveat to the use of the PLMA is the belief that it is harder to insert than other laryngeal masks. Brimacombe’s study showed that when a gum elastic bougie (GEB, Smiths Medical, Hythe, UK) guided technique is used, the PLMA can be inserted with almost complete first time success and without increasing airway trauma or patient sequelae6. The oesophageal drainage channel also allows the venting of fluid or gas reducing the risk of aspiration during the procedure. This is an important factor given that patients undergoing PDT often have non-compliant lungs requiring high airway pressures and the use of higher than normal PEEP. We described this technique in 23 patients in 20037. Since then we have gained further experience and refined our technique. As with all such procedures the patient’s lungs are ventilated with 100% oxygen, and the patient anaesthetised and given a neuromuscular blocking drug before airway manipulation. The TT is kept in place while a GEB lubricated is passed into the oesophagus. The bougie should be of the re-usable gum elastic type and is inserted ‘upside down’ (i.e. inserting the straight end, not the coude tip): both measures reduce the potential risk of oesophageal trauma. A PLMA of the appropriate size is ‘rail-roaded’ over the GEB, using the oesophageal drainage channel, until it is fully inserted. Once the PLMA cuff is inflated and the PLMA tied in place the TT is removed. The ventilator tubing is immediately attached to the PLMA with almost no interruption to ventilation. The combination of the GEB in the oesophagus and the TT tube in the trachea optimises the position of the PLMA8. Bronchoscopy is then achieved through the PLMA with all the advantages listed by the authors. We have performed over 250 PDTs in the last five years. The majority of these have been performed with the PLMA, though not all consultants in our department prefer this technique. Problems have been minor and largely restricted to difficulties with PLMA placement and adequacy of ventilation. The problems occurred mainly during the learning curves of individual practitioners and have reduced as experience has increased and since the technique has evolved to include GEB-guided PLMA placement. Problems have also occurred during the same period with PDT performed with a TT partially withdrawn or placed outside the vocal cords. These have included loss of airway control, puncture of the TT cuff and damage to the bronchoscope with the advancing needle. The fact that several techniques are advocated for this routine procedure suggests that none are a panacea. The technique chosen at present appears to be largely based on personal experience and opinion. A recently presented randomised controlled study comparing the PLMA with TT for airway management for PDT was performed in 52 patients. Although there were no differences in performance between the groups we consider this study was too small to identify clinically important differences in performance and should be considered as a pilot for a larger study9. We quite agree with the authors that a prospective study comparing techniques for airway management during PDT would be useful but believe strongly that the PLMA should be one of the designs evaluated. GM Haslam S Laver JP Nolan K Gupta TM Cook Acknowledgements We acknowledge the contributions of all of the consultant intensivists at our hospital in contributing to the information contained in this letter. References: 1. Linstedt U, Möller F, Grote N, Zenz M, Prengel A. Intubating laryngeal mask as a ventilatory device during percutaneous dilatational tracheostomy: a descriptive study. Br J Anaesth. 2007; 99: 912-5. 2. Agrò F, Carassiti M, Magnani C, Alfery D. Airway control via the CobraPLA during percutaneous dilatational tracheotomy in five patients. Can J Anaesth. 2005; 52: 418-20. 3. Johnson R, Bailie R. Airway management device (AMD) for airway control in percutaneous dilatational tracheostomy. Anaesthesia. 2000; 55: 596-7. 4. Brimacombe J. Laryngeal mask anaesthesia: principles and practice. 2nd edition. Elsevier Ltd, Philadelphia, USA 2005. ISBN 0-7020-2700-6 5. The ProSealTM laryngeal mask airway: a review of the literature. TM Cook, G Lee, JP Nolan. Can J Anesth 2005; 52: 739-760 6. Brimacombe J, Keller C, Judd DV. Gum elastic bougie-guided insertion of the ProSeal™ laryngeal mask airway is superior to the digital and introducer tool techniques. Anesthesiology 2004; 100: 25–9 7. Craven RM, Laver SR, Cook TM, Nolan JP. Use of the Pro-Seal LMA facilitates percutaneous dilatational tracheostomy. Can J Anaesth. 2003; 50 (7):718-20. 8. Dop DP, Shannon CN, Bailey PM. Efficacy and safety of the laryngeal mask airway vs Guedel airway following tracheal extubation. Can J Anaesth. 1999; 46(2):179-81. 9. Narayan P, Jagadeeswaran A, Raghuraman G. A prospective randomised controlled study comparing proseal laryngeal mask airway with endotracheal tube for the airway management during percutaneous tracheostomy in the intensive care unit. Poster presentation. The Intensive Care Society State of the Art 2007 Meeting, London 17-18th December 2007. Conflicts of Interest Dr TM Cook has been paid by the LMA company and Intavent Orthofix (both of whom manufacture the ILMA and PLMA) for lecturing. Conflict of Interest:Dr TM Cook has been paid by the LMA company and Intavent Orthofix (both of whom manufacture the ILMA and PLMA) for lecturing. |
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