Comparison of pulmonary mechanics during isoflurane, sevoflurane, and desflurane anesthesia

Abstract

Background: Practicing anesthesia clinicians are aware that tracheal intubation increases resistance and alters pulmonary mechanics; thus, comparison of bronchodilating effects of volatile agents is desirable. This study was aimed to compare the respiratory mechanics during isoflurane, sevoflurane, and desflurane anesthesia at 1 minimum alveolar concentration (MAC) and 2 MAC. Materials and Methods: Seventy patients undergoing moderate duration surgery were sequentially allocated into one of the three groups: Group I (Isoflurane; n = 23), Group S (Sevoflurane; n = 24), and Group D (Desflurane; n = 23). Peak inspiratory pressure (PIP), dynamic lung compliance (Cdyn), and airway resistance (Raw) values at three different time points were noted: 3 breaths after the start of mechanical ventilation (T1), 5 min after 1 MAC (T2), and 2 min after 2 MAC (T3). Results: PIP increased significantly in the desflurane group by 6% at 1 MAC and 8.06% at 2 MAC from the baseline. Statistically significant increase in Cdyn by 1.59% at 1 MAC and 9.9% at 2 MAC was found in sevoflurane group. Raw decreased significantly by 24.28% at 1 MAC and by 45.65% at 2 MAC from the baseline in sevoflurane group. Conclusions: We conclude that increasing concentrations from 1 MAC to 2 MAC show more consistent bronchodilating effect of Sevoflurane compared to isoflurane and desflurane. Sevoflurane increased Cdyn and reduced Raw from 1 MAC to 2 MAC.