Journal of Sound and Vibration, 1995
Authors: J. P. Mansfield and G. R. Wodicka
Conclusion: “The acoustical guidance system developed in this study offers the potential to become an inexpensive and reliable clinical device.”
“The Accuracy of distance estimation measured in the trachea to
+/- 0.8 cm over the entire insertion range is adequate to be useful in adults as well as infants. For prospective clinical use, one the ETT tip is placed through the vocal folds, the system can confirm that the tube is in the trachea and not in the esophagus through the detection of the airway reflection and an estimated cross-sectional airway area that is greater than that of the ETT. The tube can then be advanced a desired distance past the vocal cords as guided by the system.”
“In additions, any condition that reduces lumen patency such as excessive build-up of mucous or a kinked tube will be detected by the system, at which time corrective measures can be taken.”