In vivo direct measurement of the bronchodilating effect of sevoflurane using a superfine fiberoptic bronchoscope: Comparison with enflurane and halothane

摘要: Objectives: Although volatile anesthetics have been shown to spasmolytic effects on constricted airways, most previous studies were performed assess bronchodilation with indirect methods such as measurement of airway resistance, whose reliability is controversial. As the authors developed a new direct method using superfine fiberoptic bronchoscope (SFB) and confirmed accuracy this method, study assessed effect sevoflurane (S) compared enflurane (E) halothane (H). Design: Open-labeled, randomized study. Setting: The protocol was approved by Animal Care Committee in school medicine. Participants: Twenty-two mongrel dogs. Interventions: dogs anesthetized pentobarbital, IV, paralyzed pancuronium, lungs mechanically ventilated. endotracheal tube had an additional lumen insert SFB (outer diameter 2.2 mm). tip located between second third bronchial bifurcation continuously monitor cross-sectional area (BCA) or fourth generation bronchi. BCA printed out videoprinter at end expiration calculated Macintosh Ilci computer NIH (National Institutes Health) image program. Bronchoconstriction produced histamine (HA: 10 μg/kg + 500 μg/kg/hr). In first protocol, 4 used method. measured 30 60 minutes after placement also start (HA) infusion. Arterial blood (4 mL) collected measure plasma concentration catecholamines gas chromatographic mass spectrometry. 18 randomly allocated 3 groups 6 each: group S, E, H. Thirty HA infusion, subsequently inhaled following concentrations H for 15 minutes: 0.2, 0.4, 0.8, 1.6 minimum alveolar concentrations. before inhalation period each concentration. Measurements Main Results: study, no significant differences found HA. norepinephrine epinephrine changed from 138 ± 45 162 188 48 136 pg/mL, respectively. all significantly increased dose-dependent manner. There difference among three groups. Conclusion: did not change SBF could be well fixed, 30-minute interval long enough infusion produce stable bronchoconstriction. catecholamine suggest that pentobarbital anesthesia deep inhibit irritant airway. This indicates S dilates HA-constricted proximal same potency E