| Objective:The objective of this study was to investigate the influence of sevoflurane(0.3MAC-1.2MAC) on bronchial mucus transport velocity(BTV) in ventilated patients during sevoflurane-based general anesthesia.Methods:Forty patients scheduled for elective general surgery were randomized to one of four groups,receiving sevoflurane(end tidal) targeted at 0.3MAC(group 1),0.6MAC(group 2),0.9MAC(group 3) and 1.2MAC(group 4) after standardised induction with propofol,fentanil and scoline.Other drugs(propofol,fentanil,vecuronium or local anesthetics through an epidural catheter et al.) were adjusted to clinical need.A drop of methylene blue dye(approximately 0.02ml) was placed onto the dorsal surface of the left main bronchus through an epidural catheter inserted into the working channel of a fiberoptic bronchoscope.BTV was measured at 5,15 and 30 min after placement of the dye by observing the movement of it using the scope.Results:At 5min and 15min after placement of the dye,the difference of BTV between group land 2,and between group 3 and 4 was not significant (P＞0.05).BTV in group 3 was significantly lower compared to group 1 and 2(P＜0.05),and BTV in group 4 was sinificantly lower too(P＜0.05). In group 1 and 2,at 5 min after placing the dye,BTV was significantly higher than that at 15min(P＜0.05),but in both group 3 and 4,the difference of BTV at 5 min and 15min was not significant(P＞0.05). Conclusions:Anesthesia with sevoflurane may significantly depress the bronchociliary clearance in patients without lung disease,but this effect is dose dependent.On one hand,when the dose of sevoflurane is low(≤0.6MAC),the reduction of BTV is not significant,whereas when the dose is high(≥0.9MAC),BTV is significantly reduced.But there is no more reduction of BTV when the dose is changed from 0.9MAC to 1.2MAC. On the other hand,when the dose is high(≥0.9MAC),sevoflurane may significantly depress BTV in a relatively short period of time.
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