A simple mechanical device reduces subglottic injury in ventilated animals

Authors

  • Alexander J. Osborn MD, PhD,

    Corresponding author
    1. Department of Otolaryngology–Head and Neck Surgery, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
    • Send correspondence to Vito Forte, MD, Otolaryngologist in Chief, The Hospital for Sick Children, 555 University Ave., Room 6110 Elm Wing, Toronto ON M5G 1X8, Canada. E-mail: vito.forte@sickkids.ca

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  • Rose Chami MD,

    1. Department of Pathology, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
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  • Evan J. Propst MD,

    1. Department of Otolaryngology–Head and Neck Surgery, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
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  • Igor Luginbuehl MD,

    1. Department of Anesthesiology, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
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  • Glenn Taylor MD,

    1. Department of Pathology, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
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  • Joseph A. Fisher MD,

    1. Department of Anesthesiology, University of Toronto, The Toronto General Hospital, Toronto, Ontario, Canada
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  • Vito Forte MD

    Corresponding author
    1. Department of Otolaryngology–Head and Neck Surgery, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
    • Send correspondence to Vito Forte, MD, Otolaryngologist in Chief, The Hospital for Sick Children, 555 University Ave., Room 6110 Elm Wing, Toronto ON M5G 1X8, Canada. E-mail: vito.forte@sickkids.ca

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  • Presented at the American Academy of Otolaryngology–Head and Neck Surgery Annual Meeting, San Francisco CA, September 11–14, 2011.

  • Drs. Forte and Fisher have registered for a patent for the pressure modulating in-line valve under the auspices of the Commercialization Offices of the Hospital for Sick Children and the University Health Network, respectively. The authors have no other funding, financial relationships, or conflicts of interest to disclose.

Abstract

Objectives/Hypothesis

To test whether a simple inexpensive device that dynamically minimizes endotracheal cuff pressure throughout the respiratory cycle reduces endotracheal cuff pressure-related subglottic injury.

Study Design

Hypoxic animal model with one control and one experimental group.

Methods

Twelve S. scrofa domesticus piglets (14–16kg) were intubated with standard endotracheal tubes and maintained in a hypoxic state to accelerate airway injury. Animals in the control group (n = 6) were ventilated with a constant pressure of 20 cm H2O in the endotracheal tube cuff. Animals in the experimental group (n = 6) were ventilated using a custom-designed circuit that altered the pressure in the endotracheal tube cuff in synchrony with the ventilatory cycle. Larynges were harvested at the end of the experiment and examined histologically to determine the degree of airway injury induced by the endotracheal cuff.

Results

Animals in the experimental group suffered significantly less airway damage than those in the control group. The differences were seen primarily in the subglottis (aggregate damage score 6.5 vs. 12, P <0.05), where the experimental endotracheal tube cuff exerted the least pressure. There was no difference in damage to the glottic or supraglottic structures.

Conclusions

A simple, reliable, and inexpensive means of modulating endotracheal tube cuff pressure with the ventilatory cycle led to a substantial decrease in airway injury in our animal model. Such reduction in cuff pressure may prove important for humans, particularly those in intensive care units who tend to have underlying conditions predisposing them to tracheal damage from the endotracheal tube cuff.

Level of Evidence

N/A. Laryngoscope, 123:2742–2748, 2013

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