Flow Measurement in Smart Medical Inhalers I nhalers are among the most commonly used devices for treating respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). With each inhalation through the inhaler, the device delivers a specific amount of medication to the lungs. However, it is commonly misused because patients often have problems adopting the correct inhaler technique and thus re ceive insufficient medication. This leads to poor disease control and increased healthcare costs. Global annual costs associated with asthma and COPD management are substantial from both the healthcare and the societal perspectives. Research findings show that healthcare spending for an uncontrolled patient is payer Figure 5. 3D-printed inhaler clip-on containing the Sensirion flow sensor SDP3x in the side view (left) and top view (right) showing the unobstructed flow path of the inhaler. (Image: Sensirion AG) 10 20 30 40 50 60 70 80 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Time (s) Figure 1. Inhalation flow profile showing the calibrated flow rate in standard liters per minute (l/min) versus the inhalation time in seconds (s). (Image: Sensirion AG) 18 www.techbriefs.com 3.5 4.0 4.5 5.0 more than double that of a controlled patient.1 Optimal timing to release dose Studies have also found that most patients make at least one mistake during inhaler drug intake, resulting in only 7% to 40% of the drug being delivered to the lungs. The two biggest and most serious errors when using metered dose inhalers (MDIs) are both related to patient inhalation. The first error is related to the coordination between inhalation and triggering the dose release of the inhaler. Even a short delay can result in only 20% of the medication being delivered to the lungs. The second most significant error is not breathing deeply enough, which can cause another 10% less medication to reach the lungs. To address these problems, Sensirion AG (Stäfa, Switzerland) has developed a prototype that can be clipped on to the Sensor Technology, June 2022 ST Applications 0622_1.indd 18 Cov ToC 5/18/22 2:14 PM Calibrated inhaled Air-Flow Rate (I/min)http://www.techbriefs.com http://info.hotims.com/82322-850