Purpose: The present study is focused on designing an automated jet nebulizer that possesses the capability of dynamic flow regulation. In the case of existing equipment, 50% of the aerosol is lost to the atmosphere through the vent, during the exhalation phase of respiration. Desired effects of nebulization may not be achieved by neglecting this poor administration technique. There may be adverse effects like bronchospasm and exposure to high drug concentrations.
Methods: The proposed nebulizer is composed of two modes as "Compressed Air" mode and the "Oxygen Therapy" mode. The automated triggering from one mode to another will be dependent upon the percentage of oxygen saturation of the patient, monitored from the SpO2 sensor. The compressed airflow will be delivered to the patient according to the minute ventilation, derived with the aid of a temperature sensor-based algorithm. The compressor controller circuitry ensures that the patient receives optimum level of compressed air as per the flow rate. At the end of the drug delivery, if the liquid level sensor detects the absence of medication within the nebulizer chamber, the nebulization process will be terminated. The dynamic regulation of the motor speed with respect to the minute ventilation was accomplished.
Results: A laminar flow was obtained from the outlet of the compressor towards the nebulizer tubing, and a turbulent flow was obtained within the chamber. No excessive turbulent flows or rotational flow patterns were detected.
Conclusion: Detecting the drug levels in the nebulizing chamber will prevent continuous workup and useful in situations where back-to-back nebulization is required. Oxygen therapy mode identifies the patient's desaturation and important where the patient can be already hypoxic or have a ventilation-perfusion mismatch, but may be disadvantageous in severe COPD patients. The aforesaid results could certainly lead to the improvements of the existing nebulizers.
Keywords: Computational fluid dynamics; Inhalation therapy; Jet nebulizer; Proportional Integral Derivative controller.
© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2021.