Respiratory mechanics and Histology during sevoflurane anesthesia in a murine model of chronic asthma

Abstract

Sevoflurane is an anesthetic routinely used and there are no studies disclosing its effects on a chronically inflamed and remodeled airway as that found in asthma. The present study aimed to define the respiratory effects of sevoflurane in a model of chronic allergic asthma. Methods: Thirty-six BALB/c mice (20-25 g) were randomly divided into four groups. In OVA groups, mice were sensitized with ovalbumin and exposed to repeated ovalbumin challenges. In SAL groups, mice received saline using the same protocol. Twenty-four hours after the last challenge, the animals were anesthetized with pentobarbital sodium (PENTO, 20 mg/kg i.p.) or sevoflurane (SEVO, 1 MAC). Lung static elastance (Est), resistive (ΔP1) and viscoelastic/inhomogeneous (ΔP2) pressures were analyzed by end-inflation occlusion method. Lungs were fixed and stained for histopathological analysis. Results: OVASEVO group showed lower ΔP1 (38%), ΔP2 (24%), and Est (22%) than animals of OVAPENTO group (p < 0.001). Histopathology demonstrated greater airway dilation (16%) and a lower degree of alveolar collapse (25%) in OVASEVO compared to OVAPENTO group. ΔP1 was lower (35%) and airway diameters larger (12%) in SALSEVO compared to SALPENTO group. Conclusion: Sevoflurane anesthesia acted both at airway level and lung periphery reducing airway resistance, viscoelastic pressure and static elastance in chronic allergic asthma.