Airway Dimensions in the Human Determined by Non-invasive Acoustic Imaging

Study Draft to Bruno Louis at INSERM U.292, 1997 Authors: B. Louis, P. Drinker, G. M. Glass, D. Isabey and J. J. Fredberg Conclusion: “The acoustic reflection method is a powerful tool to study the physiopathological properties of the upper airways. It permits, at the bedside and in the clinical situation, an accurate non-invasive and…

Acoustic Reflectometry and Endotracheal Intubation

Anesthesia and Analgesia, 1996

Authors: D. M. Eckmann, PhD, JD, R. Glassenberg, MD, N. Gavriely, DSc, MD

Conclusion: “As an adjunct to physical examination, acoustic reflection measurements may provide a simple method to identify difficult-
to-intubate and potential failed endotracheal intubation patients not identified by physical examination and relevant medical history alone.”

Using Acoustic Reflectometry to Determine Breathing Tube Position and Patency

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…

Is Area of the Retroglossal space Differently Affected by Posture in Apneic and Nonapneic Snorers?

European Respiratory Journal, 1995 Authors: A. Monnier, B. Lousis, F. Lofaso, l. Gilain, C. Van Surell, D. Touchard, A. Harf, J. Fredberg and D. Isabey Conclusion: “In conclusion, the present acoustic results do not reveal geometrical differences between apneic and nonapneic which could have been masked in previous acoustic studies. Above all, our results demonstrate…

Acoustic Method to Estimate the Longitudinal Area Profile of Endotracheal Tubes

American Journal of Respiratory Critical Care Medicine, 1994 Authors: C. Van Surell, B. Louis, F. Lofaso, L. Beydion, L. Brochard, A. Harf, J. Fredberg, and D. Isabey Conclusion: “This study has demonstrated the feasibility of the acoustic reflection method in the intensive care unit and that the decrease in hydraulic diameter and the change in…

Pulmonary Airway Area by the Two-microphone Acoustic Reflection Method

Journal of Applied Physiology, 1994 Authors: B. Louis, G. M. Glass, and J. J. Fredberg Conclusion: “In summary, we have shown that the two-microphone method permits accurate measurement of human pulmonary airway area of breathing subjects. We established a high-pass filter signal- processing method that lessened artifacts associated with nonrigidity. This is important because it…

Acoustic Reflectometry for Airway Measurements in Man: Implementation and Validation

Clinical Physics and Physiological Measurements, 1993 Authors: I. Marshall, N.J. Maran, S. Martin, M.A. Jan, J.E. Rimmington, J.J.K. Best, G.B. Drummond, and J.J. Douglas Conclusion: “The real-time display of airway areas is able to show the complex interdependencies of movement of the mouth, tongue, soft palate, naso-pharynx and glottis. These aspects have not been accessible…

Airway Area by Acoustic Reflection: The Two-Microphone Method

Journal of Biomechanical Engineering, 1993 Authors: B. Louis, G. Glass, B. Kresen, J. Fredberg Conclusion: “In summary, the principal findings of this report are as follows. 1) Areas inferred using the two-microphone method compared favorably with the standard single microphone approach and with water displacement methods. 2) We established a correction procedure that secured both…

The Acoustic Reflection Technique for Non-invasive Assessment of Upper Airway Area

European Respiratory Journal, 1991 Authors: V. Hoffstein, J. J. Fredberg Conclusion: “It is clear from the already accumulated evidence that the acoustic technique may become a valuable tool for studying the clinical and physiological properties of the upper airway. So far this technique is the only one which allows non-invasive, accurate, reproducible and inexpensive measurements…

Acoustic Reflectometry for Airway Measurement. Principles, Limitations and Previous Work

Clinical Physics and Physiological Measurement, 1991

Authors: I. Marshall, M. Rogers, and G. Drummond

Conclusion: “Acoustic pulse reflectometry is a relatively recent technique which allows the non-invasive measurement of human airways. The technique consists of guiding an acoustic impulse through the subject’s mouth and into the airway. Suitable analysis of the
resulting reflection (the

Improvement in Upper Airway Function after Weight Loss in Patients with Obstructive Sleep Apnea

American Review of Respiratory Disease, 1988 Authors: I. Rubinstein, N. Colapinto, L. E. Rotstein, I. G. Brown, and V. Hoffstein Conclusion: “In summary, we have demonstrated that in overweight patients with OSA and abnormal pharyngeal mechanics, weight loss is associated with marked improvement in pharyngeal function, which may partly explain the observed improvement in sleep…

Effect of Mouthpiece, Nose Clips, and Head Position on Airway Area Measured by Acoustic Reflections

Journal of Applied Physiology, 1987

Authors: I. Rubinstein, P.A. McClean, R. Boucher, N. Zamel, J.J. Fredberg, and V. Hoffstein

Conclusion: “Acoustic reflection technique is so far the only relatively simple, noninvasive, reproducible, and inexpensive technique that permits the measurements of upper airway anatomy under dynamic conditions.”