Dorosz Agata, Urbankowski Tomasz, Zieliński Krzysztof, Michnikowski Marcin, Krenke Rafał, Moskal Arkadiusz
Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland.
Department of Internal Medicine, Pulmonary Diseases and Allergy, Medical University of Warsaw, Warsaw, Poland.
J Aerosol Med Pulm Drug Deliv. 2021 Dec;34(6):346-357. doi: 10.1089/jamp.2020.1663. Epub 2021 Apr 20.
The understanding of the real flow profiles through a dry powder inhaler (DPI), generated by asthma patients, is a prerequisite for satisfactory drug delivery to the lungs. The aims of the study were to assess the relationship between spirometric measures and inhalation profiles through a low-resistance DPI, and to compare parameters of those profiles between optimal and suboptimal inhalation technique type. Both healthy adult volunteers and patients with asthma were included in the study. Spirometry was conducted along with modified flow-volume test to detect expiratory levels (maximum "100%" exhalation to residual volume [RV] and halfway "50%" to RV). These were the reference levels of the depth of exhalation for each patient to simulate the effect of incomplete exhalation. Individual inhalation profiles were recorded using spirometry in-house software as the volumetric airflow through the inhaler versus time. Inspiratory flow parameters were extracted: time to peak inspiratory flow through inhaler (PIF), time at which peak inspiratory flow occurs (tPIF), total inhalation time (T), and inhaled volume during maneuver (V). There are significant relationships between spirometric indices and parameters of inhalation through a low-resistance, cyclohaler-type DPI (assessed by single-factor analysis of Spearman's rank correlation coefficient). Multiple regression models were constructed, predicting inspiratory flow parameters (including spirometric indices, demographic parameters, and inhaler's usage history as determinants). The exhalation halfway to RV before inhalation did not affect significantly PIF and tPIF (and, thus, initial flow dynamics) in asthma patients. T and V parameters were then significantly decreased, but seemed sufficient for successful DPI performance. Both exhalation to RV and incomplete exhalation halfway to RV preceding inhalation allow for effective usage of low-resistance DPI.
了解哮喘患者使用干粉吸入器（DPI）时的实际气流分布情况，是实现向肺部满意给药的前提条件。本研究的目的是评估通过低阻力DPI的肺量计测量值与吸入分布之间的关系，并比较最佳和次佳吸入技术类型之间这些分布的参数。健康成年志愿者和哮喘患者均纳入本研究。进行肺量计检查并同时进行改良流量-容积测试，以检测呼气水平（从最大“100%”呼气至残气量[RV]以及呼气至RV一半的“50%”水平）。这些是每位患者呼气深度的参考水平，以模拟不完全呼气的影响。使用肺量计内部软件记录个体吸入分布，即通过吸入器的体积气流与时间的关系。提取吸气流量参数：通过吸入器达到峰值吸气流量的时间（PIF）、峰值吸气流量出现的时间（tPIF）、总吸气时间（T）以及操作过程中的吸入量（V）。通过低阻力、环式吸入器型DPI的肺量计指标与吸入参数之间存在显著关系（通过Spearman等级相关系数的单因素分析评估）。构建了多元回归模型，以预测吸气流量参数（包括肺量计指标、人口统计学参数以及吸入器使用历史作为决定因素）。哮喘患者在吸入前呼气至RV一半并不显著影响PIF和tPIF（因此，不影响初始流动动力学）。然后T和V参数显著降低，但似乎足以实现DPI的成功性能。在吸入前呼气至RV以及呼气至RV一半的不完全呼气均允许有效使用低阻力DPI。
