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Correspondence  |   February 2007
Desflurane and Density
Author Affiliations & Notes
  • Alexandra A. Papaioannou, M.D., Ph.D., D.E.A.A.
    *
  • *University Hospital of Heraklion, Crete, Greece.
Article Information
Correspondence
Correspondence   |   February 2007
Desflurane and Density
Anesthesiology 2 2007, Vol.106, 402-403. doi:
Anesthesiology 2 2007, Vol.106, 402-403. doi:
In Reply:—
We thank very much Dr. Gunter for his useful and kind comments on our article.1 His 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.
Fig. 1. Comparison of the effect of different volatile anesthetics at equivalent concentrations on total pulmonary resistance. At 1 minimal alveolar concentration (MAC), only desflurane significantly increased pulmonary resistance compared with isoflurane and sevoflurane (  P  < 0.001 for both comparisons). The difference between isoflurane and sevoflurane was not statistically significant (  P  = 0.15). At 1.5 MAC, sevoflurane significantly increased total pulmonary resistance compared with isoflurane (  P  = 0.015), whereas desflurane caused a more pronounced increase compared with isoflurane and sevoflurane (  P  < 0.001 for all comparisons). The same findings apply at 2 MAC concentrations. Sevoflurane significantly increased pulmonary resistance compared with isoflurane (  P  < 0.001), and desflurane caused a significant increase compared with the other two volatile agents (  P  < 0.001 for both comparisons). 
Fig. 1. Comparison of the effect of different volatile anesthetics at equivalent concentrations on total pulmonary resistance. At 1 minimal alveolar concentration (MAC), only desflurane significantly increased pulmonary resistance compared with isoflurane and sevoflurane (  P  < 0.001 for both comparisons). The difference between isoflurane and sevoflurane was not statistically significant (  P  = 0.15). At 1.5 MAC, sevoflurane significantly increased total pulmonary resistance compared with isoflurane (  P  = 0.015), whereas desflurane caused a more pronounced increase compared with isoflurane and sevoflurane (  P  < 0.001 for all comparisons). The same findings apply at 2 MAC concentrations. Sevoflurane significantly increased pulmonary resistance compared with isoflurane (  P  < 0.001), and desflurane caused a significant increase compared with the other two volatile agents (  P  < 0.001 for both comparisons). 
Fig. 1. Comparison of the effect of different volatile anesthetics at equivalent concentrations on total pulmonary resistance. At 1 minimal alveolar concentration (MAC), only desflurane significantly increased pulmonary resistance compared with isoflurane and sevoflurane (  P  < 0.001 for both comparisons). The difference between isoflurane and sevoflurane was not statistically significant (  P  = 0.15). At 1.5 MAC, sevoflurane significantly increased total pulmonary resistance compared with isoflurane (  P  = 0.015), whereas desflurane caused a more pronounced increase compared with isoflurane and sevoflurane (  P  < 0.001 for all comparisons). The same findings apply at 2 MAC concentrations. Sevoflurane significantly increased pulmonary resistance compared with isoflurane (  P  < 0.001), and desflurane caused a significant increase compared with the other two volatile agents (  P  < 0.001 for both comparisons). 
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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.
Reference
Reference
Nyktari VG, Papaioannou AA, Prinianakis G, Mamidakis EG, Georgopoulos D, Askitopoulou H: Effect of the physical properties of isoflurane, sevoflurane and desflurane on pulmonary resistance in a laboratory lung model. Anesthesiology 2006; 104:1202–7Nyktari, VG Papaioannou, AA Prinianakis, G Mamidakis, EG Georgopoulos, D Askitopoulou, H
Fig. 1. Comparison of the effect of different volatile anesthetics at equivalent concentrations on total pulmonary resistance. At 1 minimal alveolar concentration (MAC), only desflurane significantly increased pulmonary resistance compared with isoflurane and sevoflurane (  P  < 0.001 for both comparisons). The difference between isoflurane and sevoflurane was not statistically significant (  P  = 0.15). At 1.5 MAC, sevoflurane significantly increased total pulmonary resistance compared with isoflurane (  P  = 0.015), whereas desflurane caused a more pronounced increase compared with isoflurane and sevoflurane (  P  < 0.001 for all comparisons). The same findings apply at 2 MAC concentrations. Sevoflurane significantly increased pulmonary resistance compared with isoflurane (  P  < 0.001), and desflurane caused a significant increase compared with the other two volatile agents (  P  < 0.001 for both comparisons). 
Fig. 1. Comparison of the effect of different volatile anesthetics at equivalent concentrations on total pulmonary resistance. At 1 minimal alveolar concentration (MAC), only desflurane significantly increased pulmonary resistance compared with isoflurane and sevoflurane (  P  < 0.001 for both comparisons). The difference between isoflurane and sevoflurane was not statistically significant (  P  = 0.15). At 1.5 MAC, sevoflurane significantly increased total pulmonary resistance compared with isoflurane (  P  = 0.015), whereas desflurane caused a more pronounced increase compared with isoflurane and sevoflurane (  P  < 0.001 for all comparisons). The same findings apply at 2 MAC concentrations. Sevoflurane significantly increased pulmonary resistance compared with isoflurane (  P  < 0.001), and desflurane caused a significant increase compared with the other two volatile agents (  P  < 0.001 for both comparisons). 
Fig. 1. Comparison of the effect of different volatile anesthetics at equivalent concentrations on total pulmonary resistance. At 1 minimal alveolar concentration (MAC), only desflurane significantly increased pulmonary resistance compared with isoflurane and sevoflurane (  P  < 0.001 for both comparisons). The difference between isoflurane and sevoflurane was not statistically significant (  P  = 0.15). At 1.5 MAC, sevoflurane significantly increased total pulmonary resistance compared with isoflurane (  P  = 0.015), whereas desflurane caused a more pronounced increase compared with isoflurane and sevoflurane (  P  < 0.001 for all comparisons). The same findings apply at 2 MAC concentrations. Sevoflurane significantly increased pulmonary resistance compared with isoflurane (  P  < 0.001), and desflurane caused a significant increase compared with the other two volatile agents (  P  < 0.001 for both comparisons). 
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