An ex vivo comparison of cuffed endotracheal tubes and self-sealing baffled endotracheal tubes

Abstract

AIMS

To compare cuffed silicone endotracheal tubes with self-sealing baffled silicone endotracheal tubes in an ex vivo canine tracheal model, to determine whether the tubes differed in their maintenance of a seal and their effectiveness in removing fluid from the tracheal lumen, and whether the self-sealing endotracheal tubes would release pressure when a closed anaesthetic circuit reached ≥30 cm H₂O.

METHODS

Twelve cadaver tracheae were randomly selected to be intubated with either cuffed or self-sealing baffled endotracheal tubes. To test tracheal seal efficacy, the tracheae were positioned vertically, 5 mL of water was instilled proximal to the tube cuff or baffles and they were monitored for leakage at 0, 15, 30, 45, and 60 minutes, recording the total volume leaked. To test fluid removal at extubation, the tracheae were intubated, then 5.6 g of 60% barium sulphate suspension was instilled proximal to the seal and left undisturbed for 5 minutes. The tubes were then extubated, with the cuffed endotracheal tubes being partially deflated before extubation, and the amount of barium recovered was weighed. These procedures were repeated on the same tracheae using the other endotracheal tubes. To test whether self-sealing baffled endotracheal tubes would release pressure at ≥30 cm H₂O, the tracheae were intubated, connected to an anaesthetic machine and pressurised to 30 cm H₂O for 5 minutes and then 50 cm H₂O for 5 minutes. Release of pressure was defined as a decrease in pressure within the closed anaesthetic circuit.

RESULTS

More cuffed (7/12) than baffled (0/12) endotracheal tubes leaked water after 60 minutes (p=0.016). The mean amount of barium removed by the self-sealing baffled endotracheal tubes (4.9 (95% CI=3.8–4.4) g) was greater than that removed by the partially deflated cuffed endotracheal tubes (0.4 (95% CI=0.14–0.66) g) (p<0.001). None of the self-sealing baffled endotracheal tubes released pressure at ≥30 cm H₂O in a closed anaesthetic circuit.

CONCLUSIONS AND CLINICAL RELEVANCE

Self-sealing baffled endotracheal tubes were more effective than cuffed endotracheal tubes at both preventing fluid leakage at the tracheal seal and removing fluid from the lumen of the trachea in cadaver tracheae. However they did not release pressure when the closed-circuit system was at ≥30 cm H₂O in a canine cadaver model. The self-sealing baffled endotracheal tubes may be a suitable substitute for cuffed endotracheal tubes.

KEY WORDS:

• Cuffed endotracheal tubes
• self-sealing baffled endotracheal tubes
• intubation
• anaesthesia

Acknowledgements

The authors acknowledge the statistical support provided by Dr. John Gay of the Department of Clinical Sciences, Washington State University. The authors would like to express thanks to Dr. Kelly McCord for his mentorship and support throughout this project.