In Reply:- I completely agree with the comment made by Dr. Nakura et al. Measurement of the cross-sectional area using an endoscope depends on the position of the image on the fiberoptic view field, as clearly shown by the figures. Distortion of the endoscopic image is inevitable for obtaining a wide-angle view, especially for a thin endoscope. To reduce this limitation, we attempted to obtain pharyngeal images on the center of the view field, as shown by Figure 2of our article. In addition, the limitation was included in the variability of measurement of the cross-sectional area presented in the Method section. Accuracy of our cross-sectional area measurement is described in more detail in our article (Am J Respir Crit Care Med 1998; 157:1204–12). I hope that this short communication stimulates manufactures to develop new technology to solve this problem in the near future.

Shiroh Isono, M.D.

Department of Anesthesiology; Chiba University School of Medicine; Inohana-cho, Chuo-ku, Japan

(Accepted for publication April 7, 1998.)