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1030 CANADIAN JOURNAL OF ANESTHESIA
CAN J ANESTH 54: 12 www.cja-jca.org December, 2007
Marc Fischler MD Hôpital Foch, Suresnes, FranceE-mail: [email protected] for publication August 29, 2007.
References 1 Bussieres JS, Lacasse Y, Cote D, et al. Modified right-
sided Broncho-CathTM double lumen tube improves endobronchial positioning: a randomized study. Can J Anesth 2007; 54: 276–82.
2 Mercier FJ, Fischler M. Is it possible to improve the shape of right double-lumen endobronchial tubes? J Cardiothorac Vasc Anesth 1995; 9: 236.
3 Lohser J, Umedaly HS, Fitzmaurice BG. Do-it-yourself modified right-sided Broncho-CathTM double lumen tube (Letter). Can J Anesth 2007; 54: 675.
Reply:We sincerely thank Professor Fischler for his interest and comments regarding our recently published article.1 The work of his team,2 published in 1995, was a trigger to our interest for right-sided double-lumen tube (R-DLT) modification. Their proposed modification consisted of cutting the distal part of the endobronchial portion to
completely remove the lateral orifice (Figure A, B). With their method, great improvement in ventilation of the right upper lobe and easier tube positioning was possible. Unfortunately, there were unresolved concerns about possible obstruction of the intermediate or superior bron-chus due to external compression by the mediastinum or from surgical manipulations. This situation can happen in the right lateral decubitus position due to the struc-tural change.
Our modification proposes an enlargement of the lateral orifice with preservation of an annulus in the distal part of the tube (Figure C, D). This conserva-tion of the extremity of the endobronchial portion of the tube acts as a stent to prevent intermediate or superior bronchial obstruction (Figure, arrows). This option also helps to stabilize tube position after insertion of the endobronchial portion. Finally, our modification is also different from Fischler’s with the broader opening it creates. This gives a larger aperture, about 180° wide, which facilitates apeture alignment with the origin of the right superior bronchus.
Thanks to the numerous readers for their positive comments. We appreciate Dr. Fischler’s support for a commercially available R-DLT. This interest is shared by many thoracic anesthesiologists.
Jean S. Bussières MD
Michel Rheault MD
Laval University Heart and Lung Institute, Laval Hospital, Québec City, CanadaE-mail: [email protected]
Laryngeal mask airways: proprietary issues
To the Editor:I write further to the letter written by Drs. Jee and van Hasselt commenting on disposable laryngeal mask airways.1 Several important points are raised by this letter. First, the letter erroneously identifies the defec-tive product as an ‘LMA’. The symbol LMA has been trademarked and identifies products (Figure, panel A) designed by Dr. Archie Brain and manufactured by the Laryngeal Mask Company Limited. There are many years of clinical investigation and superior man-ufacturing that have gone into the production of each LMA™ which might go unobserved by the user. Both ‘LMA’ and ‘LMA™’ are interchangeable. Second, it is a basically accepted principle that clinicians must inspect medical devices prior to their use. The issue of overuse and pre-use inspection of LMA™ devices was
FIGURE Photographs and schematic representation of the Broncho-Cath™ right-sided double lumen tube: the “Paris modification” (A-B) and “Quebec modification” (C-D). Note the presence of the distal part of the endobronchial portion (annulus: arrows) in the Quebec modification.
CORRESPONDENCE 1031
CAN J ANESTH 54: 12 www.cja-jca.org December, 2007
highlighted in the Journal seven years ago.1 Thirdly, single use products are subject to extreme storage and transportation stresses. LMA™ single use products have a protective “clamshell” to protect against cuff deformity during storage and transport (Figure, panel B). All LMA™ devices have features to protect against inadvertent contact with the epiglottis. The device described by Drs. Jee and van Hasselt does not.
Single use LMA™ devices have a protective and removable valve ‘stent’ to allow escape of gases used in sterilization. Injecting air into the cuff to add shape, as suggested in the letter,2 may not allow this gas to vent properly. In addition, the air will diffuse through the silicone cuff reducing the desired effect.
William StewartCEO Vitaid (Canadian distributors of the LMA™)E-mail: [email protected] for publication August 24, 2007.
References 1 Wong DT, McGuire GP. Fractured laryngeal mask air-
way (LMA) (Letter). Can J Anesth 2000; 47: 716. 2 Jee RA, van Hasselt GL. Manufacturer’s response to
a defective cuff in a disposable laryngeal mask airway (Letter). Can J Anesth 2007; 54: 681–2.
Verification of vocal cord function using the Pentax-AirwayScope®
To the Editor:The Pentax-AirwayScope® (AWS; Pentax, Tokyo, Japan) is a new rigid indirect video laryngoscope for tracheal intubation. It consists of a charge-coupled device camera, built-in colour liquid crystal device monitor and an anatomically shaped disposable intro-ducer (Pblade®) through which the camera cable passes. When the epiglottis is lifted with the tip of the Pblade®, the camera provides a view of the glottis on the monitor. The tracheal tube set in the Pblade®
is easily inserted into the trachea after adjusting the centre of the target mark in the monitor to the glot-tic opening.1,2 As a consequence of its structural features, the AWS improves the glottic view over the conventional Macintosh blade.3 Also, patients can comfortably tolerate conscious intubation, due to the anatomically shaped blade configuration.4
We recently used the AWS to verify the vocal cord function in 56-yr-old female with suspected bilateral recurrent laryngeal nerve injury following a subtotal thyroidectomy. General anesthesia was induced and maintained with propofol, remifentanil and fentanyl. The patient’s trachea was intubated after obtaining muscle relaxation with vecuronium. At the end of the operation, the surgeon identified the possibility of bilateral recurrent laryngeal nerve injury and request-ed examination of vocal cord function. The propofol and remifentanil infusions were discontinued. At the point during emergence when the patient could fol-low simple instructions such as ‘take a deep breath’, the AWS, with the rescue tube set in the channel, was inserted in the patient’s mouth and a clear view of the patient’s vocal cords was easily achieved (Figure, panel 1). The tracheal tube was then carefully withdrawn and the patient was first asked to breath hold (Figure, panel 2) and then inhale deeply (Figure, panel 3). Normal vocal cord mobility was observed, and the
FIGURE Panel A) Photo of LMA-Unique™ identifiers; Panel B) Photo of LMA-Unique™ size 3 showing “clam-shell” cuff protector.
