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Variations in ILMA external diameters: another cause of device failure

  • Carsten Preis
  • Christian Czerny
  • Irene Preis
  • Michael Zimpfer
Clinical Reports

Abstract

Purpose: To report failure of insertion of #5 and #4 intubating laryngeal mask airways (ILMAs) in a patient with a mouth opening of just under 25 mm, and the variances among same-size ILMAs.

Clinical features: A 53-yr-old man with obstructive sleep apnea underwent elective ENT surgical repair. His mouth opening was just under 25 mm. Ventilation by mask was easy. Direct laryngoscopy failed after induction of anesthesia and neuromuscular block. Neither a #5 nor a #4 ILMA could be passed between the patient’s teeth, despite different twisting maneuvres. A #4 LMA was thus prepared as a conduit for fibreoptic intubation. Placement of the LMA was easy, as was fibreoptic-guided intubation. The LMA was removed over the tracheal tube (TT) to enable ENT surgery, and the further course was uneventful. Manual examination showed that, unlike others of the same type, the failed ILMAs were not sufficiently compressible either to allow insertion in this patient or to the 20 mm reported as the maximal outer dimension of the device. Radiological examination revealed that, at the point of the device where it is intended to be compressible, the silicone layer was thicker in the failed devices than in stock compressible ILMAs, and the end of the steel tube was not so sharply beveled.

Conclusion: Our inability to insert an ILMA in a patient with an interdental distance of just under 25 mm was because the device was not sufficiently compressible although the manufacturer states the maximal outer dimension to be 20 mm.

Keywords

Obstructive Sleep Apnea Remifentanil Mouth Opening Tracheal Tube Laryngeal Mask Airway 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Résumé

Objectif: Rapporter l’échec de l’insertion de masques laryngés d’intubation nos 5 et 4 (MLI) chez un patient dont l’ouverture de la bouche était d’un peu moins de 25 mm et préciser les différences entre les MLI de même taille.

Éléments cliniques: Un homme de 53 ans, souffrant d’appnée du sommeil d’origine obstructive, a subi une réparation ORL. L’ouverture de sa bouche était d’à peine 25 mm. La ventilation par masque a été facile. La laryngoscopie directe a échoué après l’induction de l’anesthésie et le blocage neuromusculaire. Ni le MLI 5, ni le 4 n’ont pu être insérés entre les dents du patient en dépit de différentes manœuvres de torsion. Le ML 4 a alors été préparé comme un tube pour l’intubation fibroscopique. La mise en place du ML et l’intubation avec guidage fibroscopique ont été faciles. Le ML a été retiré du tube trachéale (TT) pour permettre l’intervention ORL qui s’est déroulée sans incident. L’examen manuel a d’abord montré, comparativement à d’autres du même type, que les MLI inefficaces n’étaient pas suffisamment compressibles pour permettre l’insertion ou mesuraient plus que les 20 mm reconnus comme la dimension extérieure maximale. L’examen radiologique a révélé qu’à la pointe de l’appareil, dans sa partie compressible, la couche de silicone était plus épaisse sur les dispositifs inefficaces à l’intubation que sur les autres MLI souples et que l’extrémité du tube d’acier comportait un biseau plus court.

Conclusion: Notre incapacité à insérer un MLI chez un patient dont l’ouverture de la bouche était à peine de 25 mm relevait du manque de compressibilité de l’appareil même si le fabriquant assure que la dimension extérieure maximale est de 20 mm.

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Copyright information

© Canadian Anesthesiologists 2000

Authors and Affiliations

  • Carsten Preis
    • 3
  • Christian Czerny
    • 1
  • Irene Preis
    • 2
  • Michael Zimpfer
    • 3
  1. 1.Department of Osteology/RadiologyUniversity of ViennaAustria
  2. 2.the Department of AnesthesiologyUniversity of WürzburgGermany
  3. 3.Department of Anesthesiology and General Intensive CareUniversity of ViennaViennaAustria

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