Comparative study of breathing parameters of severe asthma patients under biologic therapy through Breezhaler ® , Turbuhaler ® , NEXThaler ® and Ellipta ® dry powder inhalers
This single-center cross-sectional study demonstrates that severe asthmatic patients undergoing biologic therapy exhibit inhalation performance across four dry powder inhalers comparable to healthy subjects and superior to COPD patients, with their device-specific peak inspiratory flow and inspiratory volume showing strong correlations to baseline spirometric parameters and asthma control test scores.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
For millions of people living with severe asthma, the daily struggle is not just about the tightness in their chest, but about the mechanics of getting medicine into their lungs. Modern treatment often involves powerful biologic drugs that calm the body's overactive immune response, yet these patients still rely on handheld devices to deliver additional medication directly into their airways. The most common of these are dry powder inhalers, which look like small plastic containers. To work, they demand a specific kind of breath: the user must inhale sharply and deeply to pull the fine powder out of the device and deep into the lungs. If the breath is too weak or the technique is off, the medicine stays in the mouth or throat, leaving the lungs untreated. For decades, doctors have known that patients with chronic obstructive pulmonary disease often struggle to generate the necessary force, but it has been less clear how patients with severe asthma, especially those on the newest biologic therapies, perform when using these devices. The question is whether the improvement in their health translates to a better ability to use the tools of their treatment.
In a recent study conducted at a specialized lung center in Hungary, researchers set out to measure exactly how well these patients could breathe through four different types of dry powder inhalers. The team recruited fifty adults with severe asthma who had been receiving biologic therapy for at least two months. These patients were not just asked to take their medication; they were asked to perform a series of breathing exercises through empty versions of four specific inhaler brands: Breezhaler, Turbuhaler, NEXThaler, and Ellipta. The devices were empty to ensure the patients were not inhaling extra medication, and the researchers attached each one to a digital spirometer, a machine that records the speed and volume of air moving through the lungs. Before testing the inhalers, the patients underwent standard lung function tests to establish a baseline of their natural breathing capacity. The goal was to see if the patients' performance on the inhalers matched their general lung health and to determine if their disease control, measured by a standard questionnaire, influenced how they breathed.
The results painted a picture of patients who are surprisingly capable. When the researchers measured the speed of the air as it rushed through each device, they found that the patients generated impressive forces. On average, the patients pulled air through the Breezhaler at a speed of 103.2 liters per minute and through the Ellipta at 109.8 liters per minute. The Turbuhaler and NEXThaler, which are known to have higher internal resistance and require more effort, still saw average speeds of 75.1 and 88.9 liters per minute, respectively. Crucially, every single patient in the study was able to exceed the minimum threshold of 30 liters per minute required for these devices to work effectively. In fact, more than half of the group could generate speeds over 200 liters per minute during their standard tests, and over a quarter could reach speeds above 300 liters per minute. This performance was notably better than what has been observed in patients with chronic obstructive pulmonary disease in previous studies, suggesting that severe asthma patients on biologic therapy retain a strong ability to generate the necessary airflow.
Beyond just speed, the study looked at how much air the patients could pull into their lungs with each breath. The average volume of air inhaled through the devices ranged from 2.1 to 2.6 liters, depending on the specific inhaler used. These volumes were significantly higher than those recorded for patients with chronic obstructive pulmonary disease in similar past research. The researchers also investigated whether a patient's general lung health or their current symptom control could predict how well they would use a specific device. They found that a patient's natural peak inhalation flow, measured during standard testing, was a strong predictor of how fast they would breathe through an inhaler. Similarly, their total lung capacity predicted the volume of air they would inhale. Interestingly, the patients' scores on an asthma control test also played a role; those with better symptom control tended to generate slightly higher flow rates through the devices. This suggests that the feeling of being well-controlled is linked to the physical ability to use the inhaler effectively.
However, the study also revealed the limits of using general lung tests to predict individual performance. While the researchers could build mathematical models that accurately predicted the average performance of the entire group, these models were not precise enough to predict exactly how a single person would perform on a specific day. There was too much variation from person to person. A patient might have excellent lung capacity on paper but still struggle with the specific mechanics of one device, or vice versa. The researchers concluded that while standard lung tests and symptom scores can give doctors a good idea of what to expect from a population of patients, they cannot replace the need to observe how an individual actually uses their inhaler. The findings confirm that patients on biologic therapy are physically capable of using dry powder inhalers effectively, but the choice of device should remain a personalized decision, guided by observation rather than just general lung numbers.
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