O
An oxygen concentrator includes one or more adsorbent sieve beds operable to remove nitrogen from air to produce concentrated oxygen gas at respective outlets thereof, a product tank fluidly coupled to the respective outlets of the sieve bed(s), a compressor operable to pressurize ambient air, one or more sieve bed flow paths from the compressor to respective inlets of the sieve bed(s), a bypass flow path from the compressor to the product tank that bypasses the sieve bed(s), and a valve unit operable to selectively allow flow of pressurized ambient air from the compressor along the one or more sieve bed flow paths and along the bypass flow path in response to a control signal. The valve unit may be controlled in response to a command issued by a ventilator based on a calculated or estimated total flow of gas and entrained air or % FiO 2 of a patient.
1 . A method for estimating a fraction of inspired oxygen % FiO 2 of a patient receiving ventilatory support from a ventilator, the method comprising:
storing, for each of a plurality of measurements of a flow rate of gas expelled by one or more nozzles of a patient ventilation interface connected to the ventilator, a plurality of measurements of % FiO 2 in correspondence with a plurality of measurements of pressure in the patient ventilation interface, the patient ventilation interface including, in addition to the one or more nozzles, one or more apertures for the entrainment of additional ambient air for delivery to the patient;
measuring a flow rate of gas expelled by the one or more nozzles;
measuring a pressure in the patient ventilation interface; and
estimating the % FiO 2 of the patient based on a comparison of the measured pressure to the plurality of measurements of % FiO 2 stored for the measured flow rate.
2 . The method of claim 1 , further comprising transmitting a signal to an oxygen concentrator based on the estimated % FiO 2 .
3 . The method of claim 1 , further comprising:
storing one or more constants in association with each of a plurality of nozzle geometries,
wherein each of the one or more nozzles has a nozzle geometry corresponding to one of the plurality of nozzle geometries,
wherein said estimating the % FiO 2 of the patient is further based on the one or more constants stored in association with the nozzle geometry of the one or more nozzles.
4 . The method of claim 3 , wherein,
for each of the plurality of nozzle geometries, the associated one or more constants are stored in a memory disposed in a patient ventilation interface with a nozzle having that nozzle geometry, and
said estimating the % FiO 2 of the patient includes reading the one or more constants stored in the patient ventilation interface connected to the ventilator.
5 . A non-transitory program storage medium on which are stored instructions executable by a processor or programmable circuit to perform operations for controlling an oxygen concentrator connected to a ventilator based on a fraction of inspired oxygen % FiO 2 of a patient receiving ventilatory support from the ventilator, the operations comprising:
storing, for each of a plurality of measurements of a flow rate of gas expelled by one or more nozzles of a patient ventilation interface connected to the ventilator, a plurality of measurements of % FiO 2 in correspondence with a plurality of measurements of pressure in the patient ventilation interface, the patient ventilation interface including, in addition to the one or more nozzles, one or more apertures for the entrainment of additional ambient air for delivery to the patient;
measuring a flow rate of gas expelled by the one or more nozzles;
measuring a pressure in the patient ventilation interface; and
estimating the % FiO 2 of the patient based on a comparison of the measured pressure to the plurality of measurements of % FiO 2 stored for the measured flow rate.
6 . A ventilator comprising:
the non-transitory program storage medium of claim 5 ;
a processor or programmable circuit for executing the instructions;
a flow sensor; and
a pressure sensor, wherein
said measuring the flow rate includes communicating with the flow sensor, and
said measuring the pressure includes communicating with the pressure sensor.
7 . A ventilation system comprising:
the ventilator of claim 6 ; and
an oxygen concentrator connected to the ventilator, wherein
the operations further comprise transmitting a signal from the ventilator to the oxygen concentrator based on the estimated % FiO 2 .
8 . The ventilation system of claim 7 , wherein the oxygen concentrator includes a controller operable to generate a control signal in response to the signal transmitted from the ventilator, the control signal generated by the controller selectively allowing flow of pressurized ambient air into a product tank of the oxygen concentrator.
9 . The ventilation system of claim 8 , wherein the control signal generated by the controller operates a valve unit of the oxygen concentrator to maintain a preset oxygen concentration in the product tank according to the signal transmitted from the ventilator.
10 . The ventilation system of claim 9 , wherein the control signal generated by the controller operates the valve unit to allow the flow of pressurized ambient air to bypass one or more sieve beds of the oxygen concentrator.
11 . The ventilation system of claim 8 , wherein the control signal generated by the controller operates a compressor of the oxygen concentrator to maintain a preset oxygen concentration in the product tank according to the signal transmitted from the ventilator.
12 . The ventilation system of claim 8 , wherein the control signal generated by the controller operates a compressor external to the oxygen concentrator to maintain a preset oxygen concentration in the product tank according to the signal transmitted from the ventilator.
13 . A ventilation system comprising:
a ventilator;
a patient ventilation interface connectable to the ventilator and including one or more nozzles for expelling a flow of gas and one or more apertures for entrainment of additional ambient air for delivery to a patient;
a data storage storing, for each of a plurality of measurements of a flow rate of gas expelled by the one or more nozzles, a plurality of measurements of % FiO 2 in correspondence with a plurality of measurements of pressure in the patient ventilation interface;
a flow sensor operable to measure a flow rate of gas expelled by the one or more nozzles;
a pressure sensor operable to measure a pressure in the patient ventilation interface; and
a controller operable to estimate the % FiO 2 of the patient based on a comparison of the measured pressure to the plurality of measurements of % FiO 2 stored for the measured flow rate.
14 . The ventilation system of claim 13 , further comprising:
an oxygen concentrator connected to the ventilator, wherein
the ventilator is operable to transmit a signal to the oxygen concentrator based on the estimated % FiO 2 .
15 . The ventilation system of claim 14 , wherein the oxygen concentrator is operable to generate a control signal in response to the signal transmitted from the ventilator, the control signal generated by the oxygen concentrator selectively allowing flow of pressurized ambient air into a product tank of the oxygen concentrator.
16 . The ventilation system of claim 15 , wherein the control signal generated by the oxygen concentrator operates a valve unit of the oxygen concentrator to maintain a preset oxygen concentration in the product tank according to the signal transmitted from the ventilator.
17 . The ventilation system of claim 16 , wherein the control signal generated by the oxygen concentrator operates the valve unit to allow the flow of pressurized ambient air to bypass one or more sieve beds of the oxygen concentrator.
18 . The ventilation system of claim 15 , wherein the control signal generated by the oxygen concentrator operates a compressor of the oxygen concentrator to maintain a preset oxygen concentration in the product tank according to the signal transmitted from the ventilator.
19 . The ventilation system of claim 15 , wherein the control signal generated by the oxygen concentrator operates a compressor external to the oxygen concentrator to maintain a preset oxygen concentration in the product tank according to the signal transmitted from the ventilator.
20 . The ventilation system of claim 13 , wherein the controller is operable to estimate the % FiO 2 of the patient further based on one or more constants stored in association with a nozzle geometry of the one or more nozzles.