Atmospheric air goes to the blower of the machine through the filters. The blower compresses the air and sends high-pressure air to the connecting tube. Then the air goes to the patient through the nasal mask.
The pressure sensor senses the air pressure in the connecting tube. This sensed pressure goes to the microprocessor. Then the microprocessor analyzes the variation among the set and obtained pressure value. In case of any variation, it either increases or decreases the voltage signal of the driver motor. This, in turn, controls the speed of the blower. Based on the companies there can be some variations
Inspiration increases the volume of the lungs. This causes a sudden drop in intra-alveolar pressure. On sensing this drop of pressure, the machine applies pressure equal to IPAP. The pressure gradient (IPAP> intra-alveolar pressure) causes air to flow from the machine to the lungs. At the end of the inspiration, intra-alveolar pressure becomes equal to IPAP.
The expiration might be triggered by the drop in the air inflow to the threshold value. On, detecting the decreased air inflow, EPAP is applied by the machine. The expiration causes a fall in the intra-alveolar pressure. Once the pressure lowers below EPAP value, IPAP pressure activates again for the next breathing cycle.
