Preventing Gas Leakage Around Cuffed Endotracheal Tubes

In the Literature

Tayari H, Felisberto R, Shortland J, Briganti A, Dugdale A. Gas leakage around cuffed endotracheal tubes and the effect of gel lubrication: in vitro and ex vivo models. Vet Anaest Analg. 2026;53(1):101164. doi:10.1016/j.vaa.2025.11.008

The Research …

Endotracheal intubation is routinely performed in dogs undergoing general anesthesia to facilitate administration of oxygen and inhaled anesthetic agents and to allow the anesthetist to breathe for the patient if needed.¹ The endotracheal tube also facilitates maintenance of patency of the airway, which can be especially important in certain breeds (eg, bulldogs) and procedures (eg, rhinoscopy). Another important benefit is protection of the airway by minimizing potential for aspiration of secretions (eg, saliva and blood during dental prophylaxis) and regurgitated material.¹ Several veterinary and human studies have evaluated the impact of cuff type (high vs low pressure), changes in body position, use of sterile lubricants, and cuff inflation pressures.^2-4 The goal is to provide a good seal that prevents foreign material from contaminating the lungs without causing tracheal mucosal trauma or rupture.^1,3

This study evaluated the effect of endotracheal tube size at fixed and variable inflation pressures and the additional influence of gel lubrication in both in vitro (polyvinyl chloride [PVC] pipe to mimic a trachea) and ex vivo (pig trachea) models. The models consisted of an ≈18- to 22-mm internal diameter PVC pipe or similar-sized pig trachea (as a surrogate for the dog trachea). High-volume, low-pressure endotracheal tubes ranged from an internal diameter of 7 to 10 mm and were inflated to a cuff pressure of 30 cm H₂O. Positive pressure ventilation to an inspiratory pressure of 10 cm H₂O was then applied to assess the leak (measured by the difference in inspiratory vs expiratory volume); a leakage value of >5 mL was considered relevant for this study.

Leakage decreased as tube size increased in both models and was further reduced with application of a water-soluble gel (1 mL) prior to cuff inflation, allowing for a reduction in cuff inflation pressure. The authors noted a tracheal bulge in the ex vivo model when endotracheal tubes were inflated to a cuff pressure of 30 cm H₂O with all but the 7-mm internal diameter endotracheal tubes, raising concerns for potential mucosal damage if this pressure is routinely applied in clinical practice.

… The Takeaways

Key pearls to put into practice:

• The ex vivo model is more representative of evaluation of endotracheal tube cuff pressure that results in tracheal sealing, likely due to the expansile properties and recoil resulting from the dorsal tracheal membrane.

• Routine endotracheal tube cuff inflation to 30 cm H₂O does not consistently seal the trachea and may cause tracheal trauma.

• When possible, an endotracheal tube that more closely approximates the tracheal size allows better cuff sealing at a lower inflation pressure, resulting in less tissue trauma.

• Although evaluation was only over a short period, gel lubrication of the cuff enhanced the cuff-to-trachea sealing capacity in both models, minimizing leakage and allowing for lower cuff inflation pressures.