Marik P, Hogan J, Krikorian J
Division of Critical Care, Washington Hospital Center, Washington, DC 20010-2975, USA.
Chest. 1999 Jun;115(6):1653-7. doi: 10.1378/chest.115.6.1653.
The optimal method of delivering bronchodilators in mechanically ventilated patients is unclear. The purpose of this study was to compare the pulmonary bioavailability of albuterol delivered by the nebulizer, the metered-dose inhaler (MDI) and spacer, and the right-angle MDI adaptor in ventilated patients using urinary analysis of drug levels.
Mechanically ventilated patients who had not received a bronchodilator in the previous 48 h and who had normal renal function were randomized to receive the following: (1) five puffs (450 microg) of albuterol delivered by the MDI with a small volume spacer; (2) five puffs of albuterol delivered by the MDI port on a right-angle adaptor; or (3) 2.5 mg albuterol delivered by a nebulizer. Urine was collected 6 h after the administration of the drug, and the amounts of albuterol and its sulfate conjugate were determined in the urine by a chromatographic assay.
Thirty patients were studied, 10 in each group: their mean age and serum creatinine level were 62 years and 1.3 mg/dL, respectively. With the MDI and spacer, (mean +/- SD) 169+/-129 microg albuterol (38%) was recovered in the urine; with the nebulizer, 409+/-515 microg albuterol (16%) was recovered in the urine; and with the MDI port on the right-angle adaptor, 41+/-61 microg albuterol (9%) was recovered in the urine (p = 0.02 between groups). The level of albuterol in the urine was below the level of detection in four patients in whom the drug was delivered using the right-angle MDI adaptor.
The three delivery systems varied markedly in their efficiency of drug delivery to the lung. As previous studies have confirmed, this study has demonstrated that using an MDI and spacer is an efficient method for delivering inhaled bronchodilators to the lung. The pulmonary bioavailability was poor with the right-angle MDI port. This port should not be used to deliver bronchodilators in mechanically ventilated patients.
在机械通气患者中，支气管扩张剂的最佳给药方法尚不清楚。本研究的目的是通过尿液药物水平分析，比较雾化器、定量吸入器（MDI）加储雾罐以及直角MDI适配器在通气患者中输送沙丁胺醇的肺部生物利用度。
将在过去48小时内未接受支气管扩张剂且肾功能正常的机械通气患者随机分组，接受以下治疗：（1）使用小容量储雾罐的MDI输送5喷（450微克）沙丁胺醇；（2）通过直角适配器上的MDI端口输送5喷沙丁胺醇；或（3）雾化器输送2.5毫克沙丁胺醇。给药6小时后收集尿液，通过色谱分析测定尿液中沙丁胺醇及其硫酸酯结合物的含量。
共研究了30例患者，每组10例：他们的平均年龄和血清肌酐水平分别为62岁和1.3毫克/分升。使用MDI加储雾罐时，尿液中回收的沙丁胺醇平均为（169±129）微克（38%）；使用雾化器时，尿液中回收409±515微克沙丁胺醇（16%）；使用直角适配器上的MDI端口时，尿液中回收41±61微克沙丁胺醇（9%）（组间p = 0.02）。在4例使用直角MDI适配器给药的患者中，尿液中的沙丁胺醇水平低于检测限。
三种给药系统在将药物输送到肺部的效率上有显著差异。正如先前研究所证实的，本研究表明使用MDI加储雾罐是将吸入性支气管扩张剂输送到肺部的有效方法。直角MDI端口的肺部生物利用度较差。在机械通气患者中不应使用该端口输送支气管扩张剂。
