In Reply:—
We thank very much Dr. Gunter for his useful and kind comments on our article.1His observation that in our figure 4 the interval from baseline minimal alveolar concentration (MAC = 0) to MAC 1 is the same as that between 1 and 1.5 MAC and between 1.5 and 2 MAC is precise. This is a point that has been overlooked by the authors, but it does not alter the figure significantly (fig. 1). We decided to use only the mean values in our original figure 4 to keep it simple and easily apprehensible. Furthermore, because of the use of a laboratory model, the variations of the measurements of resistance were minimal.
The lung model used for the experiment simulates the central part of the respiratory system, mainly the trachea and the main bronchi, and our results are not explained by modeling the laboratory lung as a simple orifice. Nevertheless, our findings suggest that desflurane can increase the work of breathing in patients with upper airway obstruction. The respiratory system is much more complicated than our laboratory model, and many factors affect the overall pulmonary resistance. Because desflurane may possess a degree of bronchodilatory properties, we should await further studies in humans to clarify the clinical relevance of our observation.
*University Hospital of Heraklion, Crete, Greece. fraidako@med.uoc.gr