Flow measurement in smart inhalers for connected drug delivery

Figure 1: Inhalation flow profile - calibrated flow rate in standard liters per minute (l/min) vs inhalation time in seconds (s)
Figure 2: Drug deposition when drug is released in optimal timing window (left) vs when drug is released too late (right)
Figure 3: Parameters derived from the inhalation airflow characteristic
Figure 4: Airway resistance (RAW) can be determined from calibrated inhalation airflow characteristics
Figure 5: Typical spirometer plot of flow rate versus inhaled volume
Figure 6: Peak inspired airflow (PIF), inspired vital capacity (IVC) and airway resistance (RAW) monitored over time
Figure 7: 3D-printed inhaler clip-on containing the Sensirion flow sensor SDP3x