Abstract: A method of identifying alveolar ventilation (VA) in a subject, the method comprising: (1) using a breathing circuit which, at exhalation, keeps exhaled gas separate from inhaled gas and at inhalation, when a first gas set (FGS) flow is less than the subject's minute ventilation (VE), results in a subject inhaling FGS first and then a second gas set (SGS), for the balance of inhalation; (2) setting the FGS flow at a rate greater that VE; (3) measuring an end tidal CO2 concentration at a steady state; (4) progressively lowering the FGS flow until a time equal to a recirculation time of CO2 in the subject; and (5) deriving VA as the rate of FGS flow at the intersection between an average PETCO2 in a steady state and a line fit to the PETCO2 values after the rise in PETCO2 values begins until the recirculation time.

Abstract: A breathing circuit for use with a first gas set (FGS) and a second gas set (SGS), said circuit comprising means for keeping separate the FGS and SGS, and a means for sequentially delivering to a patient, first the FGS, and, on inspiration, when the patient inspires so as to deplete the supply of FGS into the circuit, subsequently delivers substantially SGS for the balance of inspiration.

Abstract: An apparatus to measure pulmonary blood flow and cardiac output (Q) comprising: a) a breathing circuit which, at exhalation, keeps exhaled gas separate from inhaled gas and at inhalation, when VE is greater than first gas set (FGS) flow, results in a subject inhaling FGS first and then a second gas set (SGS), for the balance of inhalation; b) a gas sensor for monitoring gas concentrations at the patient-circuit interface; c) a gas flow control means for controlling the rate of FGS flow into the breathing circuit; d) machine intelligence consisting of a computer or logic circuit capable of controlling the gas flow control means which receives the output of the gas sensor means and outputs pulmonary blood flow.

Abstract: A breathing circuit for sequential gas delivery of a first gas set (FGS) and a second gas set (SGS) employs an arrangement of conduits and active or passive valves to prevent mixing of the FGS and SGS including a valve triggered by depletion of FGS that makes the SGS available for inspiration after the FGS is depleted.

Abstract: A method of calculating the flux of any gas (x) in a CBC circuit for a ventilated or a spontaneous breathing subject, for example said gas(x) being; a) an anesthetic such as but limited to; i)N2O; ii) sevoflurane; iii) isoflurane; iv) halothane; v) desflurame; or the like b) Oxygen; c) Carbon dioxide; or the like utilizing the following relationships; Flux of gas(x)=SGF (FSX?FEX) wherein SGF=Source of gas flow into the breathing circuit (CBC circuit) in liters/minute as read from the gas flow meter as set by the anesthesiologist; FSX=Fractional concentration of gas X in the source gas (which is set by the anesthesiologist); FEX=Fractional concentration of gas X in the end expired gas as determined by a portable gas analyzer, or the like.

Abstract: A particulate blocking oxygen delivery mask includes a face piece constructed at least partially of a filtering material, a securing member such as a strap attached to the face piece, and an gas entry port disposed on the face piece. The gas entry port may include an optional one-way valve. The mask may be coupled to a continuous flow of oxygen or may be used as a partial or non-rebreathing mask. The mask permits the administration of high concentrations of oxygen to the patient while at the same time isolating the patient from any potentially contagious airborne particles in their surroundings. It also isolates any potentially contagious droplets or aerosolized particulate matter exhaled by a patient from entering the environment and potentially infecting others.

Abstract: A breathing circuit for use with a first gas set (FGS) and a second gas set (SGS), said circuit comprising means for keeping separate the FGS and SGS, and a means for sequentially delivering to a patient, first the FGS, and, on inspiration, when the patient inspires so as to deplete the supply of FGS into the circuit, subsequently delivers substantially SGS for the balance of inspiration.

Abstract: An apparatus to measure cardiac output (Q) and other parameters such as alveolar ventilation (VA), minute CO2 elimination from the lung (VCO2 ), minute oxygen consumption (VO2), oxygenated mixed venous partial pressure of CO2, (PvCO2-oxy), true mixed venous partial pressure of CO2(PvCO2), PaCO2, mixed venous oxygen saturation (SvO2), pulmonary shunt, and anatomical dead space, consisting of: a) a breathing circuit with characteristics that: i. on exhalation, exhaled gas is kept substantially separate from inhaled gas; ii.

Abstract: A method of calculating the flux of any gas (x) in a CBC circuit for a ventilated or a spontaneous breathing subject, for example said gas(x) being; a) an anesthetic such as but limited to; i)N2O; ii) sevoflurane; iii) isoflurane; iv) halothane; v) desflurame; or the like b) Oxygen; c) Carbon dioxide; or the like utilizing the following relationships; Flux of gas(x)=SGF (FSX?FEX) wherein SGF=Source of gas flow into the breathing circuit (CBC circuit) in liters/minute as read from the gas flow meter as set by the anesthesiologist; FSX=Fractional concentration of gas X in the source gas (which is set by the anesthesiologist); FEX=Fractional concentration of gas X in the end expired gas as determined by a portable gas analyzer, or the like.