Effect of High Laryngeal Mask Airway Intracuff Pressure on the Laryngopharyngeal Mucosa of Dogs

Authors

  • Regina Helena Garcia Martins MD, PhD,

    Corresponding author
    1. Departments of Otorhinolaryngology, Ophthalmology, and Head and Neck Surgery, University of São Paulo State, Botucatu, São Paulo, Brazil
    • Send Correspondence to Regina H. G. Martins, MD, PhD, Departamento de Oftalmologia, Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, UNESP, Distrito de Rubião Junior, Botucatu (SP), Brazil, 18.618–000.
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  • José Reinaldo Cerqueira Braz MD, PhD,

    1. Anesthesiology, University of São Paulo State, Botucatu, São Paulo, Brazil
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  • Júlio Defaveri MD, PhD,

    1. Pathology of the College of Medicine, University of São Paulo State, Botucatu, São Paulo, Brazil
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  • Elisa Aparecida Gregório PhD,

    1. Department of Morphology of the Institute of Bioscience, University of São Paulo State, Botucatu, São Paulo, Brazil
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  • Tânia Mara Vilela Abud MD

    1. Anesthesiology, University of São Paulo State, Botucatu, São Paulo, Brazil
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Abstract

Objectives To evaluate the effect of increased of laryngeal mask airway (LMA) intracuff pressures on the laryngopharyngeal mucosa.

Study Design Animal model.

Methods Sixteen mixed-breed dogs were randomly allocated to two groups, G1 (intracuff volume, 30 mL; n = 8) and G2 (intracuff volume, 54 mL; n = 8), to produce, respectively, high or very high intracuff pressures. Anesthesia was induced and maintained with pentobarbital. Intracuff pressures were measured immediately after insertion and inflation of a No. 4 laryngeal mask airway (LMA) and 30, 60, 90, and 120 minutes thereafter. The dogs were euthanized, and biopsy specimens from eight predetermined areas of the laryngopharynx in contact with LMA cuff were collected for light microscopic (LM) and scanning electron microscopic (SEM) examination.

Results Initial LMA cuff inflation in G1 and G2 resulted in intracuff pressures of 119 mm Hg ± 4 mm Hg and 235 mm Hg ± 13 mm Hg, respectively. Over a 2-hour period, the intracuff pressure decreased significantly in G1 (P < .001) and G2 (P < .01), and there was a significant difference between the groups over time (P < .001). The LM study of laryngopharyngeal mucosa in both groups showed mild congestion in the subepithelial layer. There were no differences between the groups (P > .10) or among the areas sampled (P > .10). In some areas of G2, the SEM study showed epithelial desquamation that was more intense than that in G1.

Conclusions The increase in LMA intracuff pressure caused only mild alterations in the laryngopharyngeal mucosa of the dog.

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