Xenon recovery from ambient pressure ventilator loop

A method for recovering and reusing Xenon from a patient's exhalations, comprising the steps of:

• administering a Xe-containing inhalation gas to a patient with a ventilator;
• directing exhaled breath comprising CO2, O2, N2, and Xe from the patient to a feed side of a polymeric membrane where a permeate gas enriched in CO2, O2, and N2 and depleted in Xe preferentially permeates through the membrane to a permeate side thereof, the polymeric membrane having the properties of:
• a N2 permeance>40 GPU [10−6 cm3 (STP)/cm2·s·cm(Hg)],
• a CO2 permeance>250 GPU [10−6 cm3 (STP)/cm2·s·cm(Hg)], and
• a N2/Xe selectivity>3 at ambient temperature/pressure conditions;
• withdrawing a residue gas enriched in Xe and depleted in CO2, O2, and N2 from a residue port of the polymeric membrane;
• and
• adding makeup O2 and makeup Xe to the residue gas to provide the inhalation gas mixture.

A method for recovering and reusing Xenon from a patient's exhalations, comprising the steps of:

• administering a Xe-containing inhalation gas to a patient with a ventilator;
• directing exhaled breath comprising CO2, O2, N2, and Xe from the patient to a feed side of a first membrane where a first permeate gas enriched in CO2, O2, and N2 and depleted in Xe preferentially permeates through the first membrane to a permeate side thereof, the first membrane including a primary gas separation medium comprising a perfluorinated cyclic ether polymer;
• withdrawing a first residue gas enriched in Xe and depleted in CO2, O2, and N2 from a residue port of the first membrane;
• directing the first permeate gas from the permeate side of the first membrane to a feed side of a second membrane where a second permeate gas enriched in CO2, O2, and N2 and depleted in Xe preferentially permeates through the second membrane to a permeate side thereof, the second membrane including a primary gas separation medium comprising a perfluorinated cyclic ether polymer;
• withdrawing a second residue gas enriched in Xe and depleted in CO2, O2, and N2 from a residue port of the second membrane;
• and
• combining makeup O2, makeup Xe, and the first and second residue gases to provide the inhalation gas mixture.

A system for recovering and reusing Xe from an Xe-containing exhalations of a patient, comprising:

• a ventilator adapted and configured to administer an inhalation gas containing Xe to a patient and collect the patient's exhalations;
• a membrane based on poly(perfluoro-2,2-dimethyl-1,3-dioxole) having a feed side, a permeate side, and a residue port, said feed side being in fluid communication with said ventilator to receive the patient's exhalations comprising CO2, N2, O2, and Xe, said membrane being adapted and configured to receive the patient's exhalations at said feed side and separate the patient's exhalations into a permeate gas enriched in CO2, N2, and O2 and a residue gas enriched in Xe;
• a return tube in fluid communication with said residue port;
• a source(s) of makeup O2 and makeup Xe in fluid communication with said return tube;
• a microprocessor adapted to control addition of makeup O2 and makeup Xe from said source(s) to a residue gas in said tube;
• and
• a gas analyzer adapted to measure levels of O2 and Xe in the combined makeup O2, makeup Xe, and residue gas, wherein the microprocessor's controlled addition of makeup O2 and makeup Xe is based upon the levels of O2 and Xe measured by said analyzer and predetermined desired levels of O2 and Xe in the inhalation gas.

A method of recovery Xe from a patient's exhalations, comprising the steps of:

• feeding a patient's exhalations from a ventilator to a membrane where it is separated into a CO2 and N2 enriched permeate and a Xe-enriched residue, the membrane being made of polymers or copolymers based on perfluoro-2,2-dimethyl-1,3-dioxole;
• adding makeup Xe and makeup O2 to the Xe-enriched residue;
• and
• directing the combined makeup Xe, makeup O2, and Xe-enriched residue to the ventilator.