Respiratory devices supply respiratory gas mechanically to patients with impaired respiratory function. The respiratory gas is usually enriched with oxygen and conveyed into the lung with a positive pressure generated by the device. There are two fundamentally different respiration methods: During controlled respiration, the ventilator fully assumes the patient's respiration effort with preset respiratory volume or pressures, while in assisted respiration the respiratory device merely supports the spontaneous breathing effort with a set overpressure. Modern respiratory devices automatically adjust the inhalations and exhalations to the patient's needs. Respiratory devices are available in various versions – as emergency respiratory devices for rescue application, long-term respiratory devices for intensive care and mobile home respiratory devices.
An important feature when controlling (triggering) high-quality respiratory devices is the early detection of the patient's inhalation phase via a flow trigger. Only in this way can the device assist a spontaneous breath with a preset overpressure, while keeping the patient's respiratory effort to a minimum. At the same time, the measurements need to be highly accurate over the entire flow range for many treatments in order to detect the patient's respiratory pattern reliably. In today's respiratory devices, the spontaneous breathing effort and entire respiratory activity of the patient is therefore usually monitored by a highly sensitive thermal mass flow sensor or a highly dynamic differential pressure sensor.
In addition, the set respiratory pressure and tidal volume administered to the patient must be monitored precisely in respiratory devices in order to ensure safe functioning and hence treatment success.
First Sensor provides highly sensitive and rapid thermal mass flow sensors as well as special versions of its flow-based LME and LDE differential pressure sensors with resolutions of 0.01% in the lower pressure range and, at the same time, dynamic measuring ranges greater than 10,000. These special sensors detect minute flow rates around the zero point of the respiratory flow and also measure flow rates of several hundred l/min. We also develop and manufacture customized multi-sensor modules as a simple plug-and-play solution for respiratory devices. The modules integrate multiple sensors to form fully calibrated and tested systems with signal processing and definite interfaces.