A Comparison of Laser-Protected Endotracheal Tubes

Abstract

Objectives

To compare the physical characteristics of 3 laser-protected endotracheal tubes (LPETs) commonly used in endoscopic laser surgery. To report potential intraoperative problems related to LPET use and suggest practical solutions.

Study Design

Comparative analysis.

Setting

Academic laboratory.

Subjects and Methods

Physical characteristics of the Mallinckrodt Laser-Flex (MTL), Medtronic Laser-Shield II (ML-II), and Rusch LaserTubus (RL) were compared. The effect of bending LPETs on airflow resistance was estimated with a pressure transducer. The force required to pull each tube through the glottis and the pressure exerted during this maneuver were measured in a fresh cadaveric human larynx.

Results

The design features and physical characteristics of LPETs differ, including varying balloon-tip lengths. Bending LPETs to acute angles caused significant pressure increase within the RL tube (Δ 3.42 cm H₂O) and minimal change within the ML-II (Δ 0.12 cm H₂O) and MTL (Δ 0.21 cm H₂O) tubes. The average force required to pull the RL (48.12 g, P = .003) and MTL (282.4 g, P = .001) tubes through the glottis was 7.6× and 44.5× greater than that for the ML-II (6.39 g). When pulled through the vocal folds, the ML-II cuff exerted no detectable pressure, whereas higher pressures were measured for the RL (2.2 cm H₂O) and MTL (6.5 cm H₂O) tubes.

Conclusion

The ML-II tube had the most favorable characteristics, with minimal pressure during extubation and resistance to kinking. The RL tube kinks readily with a resultant increase in resistance to airflow. The MTL tube extends farther into the trachea due to a relatively elongated balloon-tip configuration. Future LPET designs should incorporate features that avoid intraoperative difficulties related to airway protection and ventilation.