In respiratory monitoring, breathing activity, frequency, intensity, and the function of the involved organs are measured using pressure sensors. The following devices employ relative pressure sensors, differential pressure sensors, and absolute pressure sensors:
Healthy sleep through CPAP therapy
CPAP* Devices
Sleep apnea is a sleep disorder affecting millions of people, characterized by abnormal pauses in breathing or unusually shallow breathing during sleep. CPAP devices use a low, positive air pressure to keep the airways open and enable regular breathing patterns.
- Differential or bidirectional differential pressure sensors in the low-pressure range of 50 to 100 mbar, such as the AMS 5935, are used in these applications.
*Continuous Positive Airway Pressure (CPAP)
Respirators
Respirators are life-saving devices for patients who cannot breathe independently, such as during anesthesia. They deliver breathable air into and out of the lungs and are found everywhere, from intensive care units to portable home devices. In addition to an absolute pressure sensor to measure ambient pressure, a low-pressure sensor is required to provide feedback to a microcontroller about the air pressure in the mask or supply hose for measuring and regulating the respiratory pressure. OEM sensors are particularly well-suited for these applications:
- AMSYS offers a variety of differential and bidirectional low-pressure sensors operating in the range of 40 to 100 mbar, including the analog/digital AMS 5812 or the purely digital AMS 5935.
- Ambient pressure is measured using barometric pressure sensors (absolute pressure range 700–1250 mbar), such as the MS5849 or AMS 5915. These measurements allow the adjustment of respiratory air to changes in altitude or atmospheric pressure in the patient’s environment.
Spirometers
Spirometers are non-invasive devices used to measure the flow volume of inhaled and exhaled air. They dynamically measure lung volume, providing insights into lung function.
- A proven method for this measurement involves using a bidirectional low-pressure sensor in the range of 20–150 mbar, which can directly measure the air volume in both directions.
Enhanced media compatibility for HVAC applications can be achieved with bidirectional pressure sensors such as the SM9336 or AMS 5935.
Oxygen Concentrators
Oxygen concentrators are used to extract oxygen from a gas reservoir (typically ambient air). The oxygen-enriched air can then be used for oxygen therapy. Alternatively, they can be used to treat patients with pulmonary conditions requiring a higher oxygen concentration than what is available in ambient air.
- To measure the increased oxygen concentration, absolute pressure sensors operating in the range of 1 to 2 bar, such as the highly accurate MS5803, are employed. This sensor is also available in variants for 1, 2, 5, 7, 14, and 30 bar absolute pressure.