Simulated laryngoscopy with supraglottic high-pressure source ventilation: an in vitro study of tracheal airflow to determine optimal positioning of laryngoscope and jet ventilation cannula.

PURPOSE: To investigate how variations in positioning of laryngoscope and location of jet cannula on the laryngoscope body influence tracheal airflow during simulated high-pressure source supraglottic (HPSV) jet ventilation laryngoscopy using an anatomical model.

METHODS

A Broncho Boy Bronchoscopy model was modified to allow recording of tracheal airflow. A laryngoscope was suspended and positioned to simulate laryngoscopy. HPSV was delivered by a jet cannula attached to the body of the laryngoscope. Different combinations of laryngoscope angulation and cannula attachment were used and air flow recorded for each combination. Statistical analysis assessed the variations in flow.

RESULTS

Significant statistical differences in flow effect (P < 0.05) were shown, indicating that laryngoscope position and attachment of jet cannula have a significant effect on tracheal airflow. Highest flows were achieved by anterior positioning of laryngoscope combined with anterolateral attachment of cannula (> 1 L/s) compared to downward or either side (< 0.6 L/s).

CONCLUSION

Significant differences in tracheal airflow arise from different positions of both laryngoscope and jet cannula with supraglottic HPSV. Optimal locations for both are apparent and collaborative interaction with anaesthetist emphasised. The experimental setup could be a potential simulation tool.