Letters to the Editor
1 University of Miami, School of Medicine, Miami, FL 33101
2 Childrens Hospital, San Francisco, CA 94118
We appreciate Dr Kattwinkel's concerns and we would like to clarify several of his comments:
1. Comparison of work of breathingDr Kattwinkel correctly points out that, by adding the PE 20 sampling catheter, we have increased the resistance of the nasal prongs over their resistance when used clinically. In fact, the catheter does increase the measured resistance of the nasal prongs by about 36%. We must concur that work of breathing measured with the nasal prongs would have been less if the sampling catheter was not present.




