Pulmonary mechanics during isoflurane, sevoflurane and desflurane anaesthesia

TLDR

The study aimed to compare the bronchial smooth muscle tone effects of desflurane with isoflurane and sevoflurane after intubation. Patients were randomized into three groups receiving isoflurane, sevoflurane, or desflurane, and peak inspiratory pressure, respiratory resistance, and dynamic compliance were measured at baseline, 5 min 1 MAC, and 5 min 2 MAC. At 1 MAC all agents lowered peak inspiratory pressure and respiratory resistance while raising dynamic compliance; at 2 MAC desflurane increased airway resistance and pressure and reduced compliance, whereas sevoflurane and isoflurane maintained bronchodilation.

Abstract

Summary This study was designed to investigate the effects of desflurane on bronchial smooth muscle tone, following intubation and to compare these effects with isoflurane and sevoflurane. Patients were randomly divided into three groups to receive, isoflurane ( n = 22), sevoflurane ( n = 23), or desflurane ( n = 22). Peak inspiratory pressure (PIP), respiratory resistance (Rr) and dynamic compliance (Cdyn) measurements were recorded at three time points; After the beginning of ventilation and before inhalation agent was started, following 5 min of ventilation with 1 MAC (minimum alveolar concentration) inhalation agent and following 5 min of 2 MAC inhalation agent. We found that all inhalation agents caused a significant decrease in Peak Inspiratory Pressure (PIP) and respiratory resistance (Rr), and an increase in dynamic compliance (Cdyn) at 1 MAC concentrations. When the agent concentration was increased to 2 MAC, desflurane caused a significant increase in Rr and PIP and a decrease in Cdyn. We concluded that desflurane, like isoflurane and sevoflurane, exhibits a bronchodilator effect at 1 MAC concentration. However, increasing the concentration to 2 MAC caused an increase in airway resistance with desflurane, whilst sevoflurane and isoflurane continued to have a bronchodilator effect.