Christensen E F, Nørregaard O, Jensen L W, Dahl R
Department of Respiratory Diseases, University Hospital of Aarhus, Denmark.
Chest. 1993 Oct;104(4):1108-13. doi: 10.1378/chest.104.4.1108.
Positive expiratory airway pressure seems to dilate narrowed or collapsed airways, but this may be accompanied by a maintained and harmful increase in resting lung volume in obstructive pulmonary disease.
To evaluate the influence of inhaled terbutaline and positive expiratory pressure (PEP) on airway resistance (Raw) and functional residual capacity (FRC) in bronchial asthma.
Randomized crossover design, single blind with regard to inhaled medication, open with regard to PEP (PEP can be felt).
Ten patients with bronchial asthma inhaled placebo and terbutaline in doses of 0.125 mg, 0.5 mg, and 1.5 mg by cone spacer combined with a facemask giving 0, 10, or 15 cm H2O PEP on separate days. FRC and Raw were measured by body plethysmography before and after inhalations. Data were analyzed by analysis of variance with terbutaline dose and PEP as factor levels.
The effect of terbutaline: Raw decreased significantly (p < 0.0001) after 0.125 mg and 1.5 mg. The FRC did not change significantly. The effect of PEP: Raw decreased, but significantly only when the dose of 1.5 mg terbutaline was excluded from the analysis. Raw decreased with PEP 10 and 15 cm H2O, mean 0.6 (95 percent CI: -1.1, -0.2) and 0.9 (95 percent CI: -1.3, -0.4) cm H2O/L/s. The FRC did not change significantly with the PEP level.
PEP only had influence on Raw when insufficient doses of terbutaline were inhaled, whereas once an efficient dose of terbutaline was administered, significant bronchodilation was achieved with or without PEP. Positive expiratory pressure did not increase FRC.
呼气末正压似乎可扩张狭窄或塌陷的气道，但在阻塞性肺疾病中，这可能伴随着静息肺容积的持续且有害的增加。
评估吸入特布他林和呼气末正压（PEP）对支气管哮喘患者气道阻力（Raw）和功能残气量（FRC）的影响。
随机交叉设计，对吸入药物采用单盲，对PEP采用开放设计（可感觉到PEP）。
10例支气管哮喘患者通过锥形 spacer 联合面罩，在不同日期分别吸入安慰剂以及剂量为0.125mg、0.5mg和1.5mg的特布他林，同时给予0、10或15cmH₂O的PEP。在吸入前后通过体容积描记法测量FRC和Raw。以特布他林剂量和PEP作为因素水平，采用方差分析对数据进行分析。
特布他林的作用：吸入0.125mg和1.5mg后，Raw显著降低（p<0.0001）。FRC无显著变化。PEP的作用：Raw降低，但仅在分析中排除1.5mg特布他林剂量时才具有显著性。PEP为10cmH₂O和15cmH₂O时Raw降低，平均分别为0.6（95%CI：-1.1，-0.2）和0.9（95%CI：-1.3，-0.4）cmH₂O/L/s。FRC随PEP水平无显著变化。
仅在吸入特布他林剂量不足时，PEP才对Raw有影响，而一旦给予有效剂量的特布他林，无论有无PEP均可实现显著的支气管扩张。呼气末正压未增加FRC。
