Evidence of Adequacy of the Performance of the Pulvinal™ by Measuring Through-Device Peak Inspiratory Flow Rate in Severe Airways Obstruction in Adults and Children

Pulvinal™ is a novel DPI designed to deliver inhaled drugs to the airways. Previous in vitro and in vivo data has suggested that the peak inspiratory flow rate (PIFR), measured through Pulvinal™, does not depend on the severity of expiratory airflow obstruction and that the lowest PIFR values seem sufficient to deliver an effective bronchodilator dose. To study this further, we have investigated through-Pulvinal™ PIFR in categories of patients who are likly to generate low inspiratory flow rates. Three different patients' groups were selected (severe asthmatics, n = 52, including elderly) patients with severe chronic obstructive pulmonary disease (COPD, n = 21) and children with asthma (n = 16). This study aimed to measure the through-device PIFR and also to assess whether this correlated with measures of expiratory flow rate. Inspiratory flow measurements were made with a Pulvinal™ inhaler inserted into the adapted mouthpiece of a pneumotochograph. No significant correlations were seen between through-device PIFR and expiratory volumes or flow rates when expressed as percent predicted normal (forced expiratory volume in 1 sec [FEV₁] and peak expiratory flow rate [PEFR]) in any of the three studied populations. A significant correlation was present for FEV₁ (when expressed in liters) and through-device PIFR in the adult asthmatic and COPD study groups. In spite of the disease severity in adult populations and the age of children, the lowest generated PIFR values were within the range producing adequate performance of Pulvinal™ DPI (>20 L/min). We conclude that inspiratory flow rates generated through the Pulvinal™ inhaler can be adequate in asthma and COPD, including patients at the extremes of severity and age, who may theoretically have a limitation in their inspiratory flow.