Malliotakis Polychronis, Linardakis Manolis, Gavriilidis George, Georgopoulos Dimitris
Intensive Care Medicine Department, University Hospital of Heraklion, University of Crete, PO Box 1352, 71110 Heraklion, Crete, Greece.
Crit Care. 2008;12(6):R140. doi: 10.1186/cc7117. Epub 2008 Nov 14.
Delivery of bronchodilators with a metered-dose inhaler (MDI) and a spacer device in mechanically ventilated patients has become a widespread practice. However, except for the short-acting beta2-agonist salbutamol, the duration of action of other bronchodilators, including long-acting beta2-agonists, delivered with this technique is not well established. The purpose of this study was to examine the duration of bronchodilation induced by the long-acting beta2-agonist salmeterol administered with an MDI and a spacer in a group of mechanically ventilated patients with exacerbation of chronic obstructive pulmonary disease (COPD).
Ten mechanically ventilated patients with acute exacerbation of COPD received four puffs of salmeterol (25 microg/puff). Salmeterol was administered with an MDI adapted to the inspiratory limb of the ventilator circuit using an aerosol cloud enhance spacer. Static and dynamic airway pressures, minimum (Rint) and maximum (Rrs) inspiratory resistance, and the difference between Rrs and Rint (DeltaR) were measured before and at 15, 30, and 60 minutes as well as at 2, 3, 4, 6, 8, 10, and 12 hours after salmeterol administration. The overall effects of salmeterol on respiratory system mechanics and heart rate during the 12-hour study period were analyzed by nonparametric Wilcoxon signed rank test.
Salmeterol caused a significant decrease in dynamic and static airway pressures, Rint, and Rrs. These changes were evident at 30 minutes and remained significant for 8 hours after salmeterol administration. The duration of bronchodilation varied significantly among patients, lasting in some patients more than 10 hours and wearing off in others in less than 6 hours.
It is concluded that four puffs of salmeterol delivered with an MDI and a spacer device induces significant bronchodilation in mechanically ventilated patients with COPD exacerbation, the duration of which is highly variable, precluding definite conclusions in regard to optimum dosing schedules.
在机械通气患者中，使用定量吸入器（MDI）和储雾罐装置输送支气管扩张剂已成为一种广泛应用的做法。然而，除了短效β2激动剂沙丁胺醇外，包括长效β2激动剂在内的其他支气管扩张剂通过这种技术输送后的作用持续时间尚未明确。本研究的目的是在一组慢性阻塞性肺疾病（COPD）加重的机械通气患者中，研究使用MDI和储雾罐给予长效β2激动剂沙美特罗所诱导的支气管扩张持续时间。
10例COPD急性加重的机械通气患者接受4喷沙美特罗（每喷25微克）。沙美特罗通过一个与呼吸机回路吸气支适配的MDI并使用雾化增强储雾罐给药。在给予沙美特罗前以及给药后15、30和60分钟以及2、3、4、6、8、10和12小时测量静态和动态气道压力、最小（Rint）和最大（Rrs）吸气阻力以及Rrs与Rint的差值（DeltaR）。通过非参数Wilcoxon符号秩检验分析沙美特罗在12小时研究期间对呼吸系统力学和心率的总体影响。
沙美特罗使动态和静态气道压力、Rint和Rrs显著降低。这些变化在30分钟时明显，并在给予沙美特罗后8小时内仍显著。支气管扩张的持续时间在患者之间差异显著，在一些患者中持续超过10小时，而在另一些患者中不到6小时就消退了。
得出的结论是，使用MDI和储雾罐装置给予4喷沙美特罗可在COPD加重的机械通气患者中诱导显著的支气管扩张，其持续时间高度可变，无法就最佳给药方案得出明确结论。
