Dual Pressure Sensor Patient Ventilator
A patient ventilation apparatus is disclosed. The apparatus includes an inlet port connectible to an oxygen source with pressurized oxygen enriched gas. An outlet port is connectible over a gas delivery conduit to a patient interface configured for fitment on a patient respiratory passageway. A valve is in pneumatic communication with the inlet port and with the outlet port. A first pressure sensor measures a patient interface pressure, which is connectible to the first pressure sensor over a pressure sensor line. A second pressure sensor measures a valve output pressure. A controller is in communication with the first pressure sensor, the second pressure sensor, and the flow sensor, to detect a patient inspiratory phase and a patient expiratory phase based upon a combination of measurements of the first pressure sensor and the second pressure sensor and to regulate the valve to selectively deliver pressurized oxygen enriched gas to the patient interface.
1 . A ventilation apparatus comprising:
an inlet port connectible to an oxygen source with pressurized oxygen enriched gas;
an outlet port connectible over a gas delivery conduit to a patient interface configured for fitment on a patient respiratory passageway;
a valve with an input in pneumatic communication with the inlet port and an output in pneumatic communication with the outlet port;
a first pressure sensor measuring a patient interface pressure, the patient interface being connectible to the first pressure sensor over a pressure sensor line;
a second pressure sensor measuring a valve output pressure; and
a controller in communication with the first pressure sensor and the second pressure sensor, a patient inspiratory phase and a patient expiratory phase being detectable by the controller based upon a combination of measurements of the first pressure sensor and the second pressure sensor to regulate the valve to selectively deliver the pressurized oxygen enriched gas to the patient interface.
2 . The ventilation apparatus of claim 1 , wherein a diameter of the valve in a fully open position is greater than a diameter of the gas delivery conduit.
3 . The apparatus of claim 1 , further comprising:
a flow sensor measuring a gas flow rate and in-line with the output of the valve and the outlet port;
wherein the controller detects the patient inspiratory phase and the patient expiratory phase based upon a combination of measurements of the first pressure sensor, the second pressure sensor, and the flow sensor.
4 . The apparatus of claim 3 , wherein the controller regulates the delivery of the pressurized oxygen enriched gas to the patient interface according to a trigger limit and a cycle limit reached by the gas flow rate.
5 . The apparatus of claim 4 , wherein an average gas flow rate over one or more patient breathing cycles defines a leak constant.
6 . The apparatus of claim 5 , wherein the trigger limit is defined by the leak constant added to a trigger constant.
7 . The apparatus of claim 4 , wherein the cycle limit is defined by a cycle constant fraction of a maximum flow rate.
8 . The apparatus of claim 3 , wherein the controller opens the valve to induce a flow of the pressurized oxygen enriched gas to the patient interface and closes the valve to reduce the flow.
9 . The apparatus of claim 3 , wherein the controller includes a first proportional-integral-derivative (PID) controller and a second PID controller, the first PID controller being part of a first control loop over the gas flow rate, and the second PID controller, together with the first control loop, being part of a second control loop for minimizing error between the patient interface pressure and a set pressure.
10 . The apparatus of claim 1 , wherein the controller opens the valve to induce a pressure differential at the patient ventilation interface and closes the valve to reduce the pressure differential.
11 . The apparatus of claim 1 , wherein the controller regulates the delivery of the pressurized oxygen enriched gas to the patient interface according to a trigger limit and a cycle limit reached by the pressure differentials between the patient interface pressure and the valve output pressure.
12 . The apparatus of claim 11 , wherein an average pressure differential over one or more patient breathing cycles defines a leak constant.
13 . The apparatus of claim 12 , wherein the trigger limit is defined by the leak constant added to a trigger constant.
14 . The apparatus of claim 11 , wherein the cycle limit is defined by a cycle constant fraction of a maximum pressure differential.
15 . The apparatus of claim 1 , wherein the controller includes a first proportional-integral-derivative (PID) controller and a second PID controller, the first PID controller being part of a first control loop over the valve pressure, and the second PID controller, together with the first control loop, being part of a second control loop for minimizing error between the patient interface pressure and a set pressure.
16 . The apparatus of claim 1 , wherein the gas delivery conduit and the pressure sensor line are integrally formed.
17 . The apparatus of claim 1 , wherein the gas delivery conduit and the pressure sensor line are separated.
18 . The apparatus of claim 1 , wherein the oxygen source is a tank containing the pressurized oxygen enriched gas.
19 . The apparatus of claim 1 , wherein the oxygen source is an oxygen concentrator in pneumatic communication with a compressor.
20 . The apparatus of claim 19 , wherein:
the oxygen concentrator outputs oxygen enriched gas at a first pressure level to the compressor; and
the compressor includes a pump having an input pneumatically coupled to the oxygen concentrator and an output pneumatically coupled to an accumulator which outputs the pressurized oxygen enriched gas at a second pressure level different from the first pressure level.