The present disclosure generally relates to systems and methods for delivery of therapeutic gas to patients, using techniques to compensate for disruptions in breathing gas flow measurement, such as when breathing gas flow measurement is unavailable or unreliable. Such techniques include using historical breathing gas flow rate data, such as moving average flow rates, moving median flow rates and/or flow waveforms. At least some of these techniques can be used to ensure that interruption in therapeutic gas delivery is minimized or eliminated.

Described here are closed-circuit breathing devices and methods for their use. In general, the closed-circuit breathing device is configured to achieve a steady-state equilibrium, whereby therapeutic gas is introduced into the breathing circuit in small, controlled volumes until a steady state concentration of the therapeutic gas is reached. During this time, the closed-circuit breathing device is operated in a true closed circuit, such that the therapeutic gas is not lost to the atmosphere. Safety measures are built into the closed-circuit breathing device so that a hypoxic mixture is not delivered to the subject. The therapeutic gas may be xenon.

Systems and method are provided for monitoring a patient during surgery. An anesthetic machine includes a ventilator configured to provide breathable gas to a patient, an oxygen concentration sensor configured to monitor the concentration of oxygen in gas inhaled and exhaled by the patient, and a respiratory monitor configured to monitor a respiratory rate and a tidal volume of the patient. An uptake rate estimator is configured to estimate a pulmonary oxygen uptake rate (ViO2) for the patient from the concentration of oxygen in gas inhaled and exhaled by the patient and a minute volume of the patient. A risk score calculator is configured to determine a risk score for the patient at each interval as a function of the estimated ViO2 value. An output device is configured to provide the determined risk score to a human operator.

The invention relates to a mechanical ventilation system (10) for respiration of a patient (5), the system being adapted for providing decision support for mechanical ventilation. Control means (12) is adapted for using both first data (D1) and second data (D2), indicative of the respiratory feedback in the blood, in physiological models (MOD) descriptive of, at least, lung mechanics, and/or gas exchange in the lungs of the patient, the physiological models comprising a number of model parameters (MOD_P). The control means is further arranged for simulating the effect on one, or more, model parameters (MOD_P) of the physiological models for a suggested value of the positive end expiratory pressure (PEEP) setting for the ventilation means, and thereby provide decision support in relation to said suggested PEEP value. The invention is advantageous for providing mathematical based models of changes in physiology in response to changes in ventilator settings of the PEEP thereby allowing mathematical physiological models to predict changes in clinical variables for a given value of PEEP.

A method of detecting hypoxia. Detecting hypoxia includes detecting, in exhaled breath, at least one indicator for hypoxia. The at least one indicator is selected from the group consisting of pentanal, 2-pentanone, 2-hexanone, 2-heptanone, 2-cyclopenten-1-one, and 4-butyrolactone.

The embodied invention is a new inspiration/expiration ventilator flow design, with a constant inspiration flow and intermittent-concurrent expiratory flow based on lung pressure setpoints. This mode is possible by using a new dual lumen tube inserted into a patient Trachea. Additionally, the control provides support for patient initiated breathing which is initiated by a lung pressure drop. This control provides continuous and gentle recruitment of lung alveoli.

A universal respiratory detector for detecting a respiratory gas. The universal respiratory detector may include a plurality of layers with a visual indicator to quickly and reversibly change color to detect a respiratory gas parameter such as carbon dioxide. The color change may be visible from both sides of the detector. In some examples, the respiratory detector may be a biocompatible and conformable sticker for mounting on a person's face or an oxygen delivery device.

A check valve can include a pressure actuator or an electromagnetic actuator. The check valve includes a valve inlet, a valve outlet, and flap disposed between the valve inlet and the valve outlet. The pressure actuator in fluid communication with the valve inlet. The check valve has an open state and a closed state. The check valve is configured to allow an input gas to flow from the valve inlet to the valve outlet when the check valve is in the open state. The check valve is configured to preclude the input gas from flowing from the valve inlet to the valve outlet when the check valve is in the closed state. Upon actuation of the pressure actuator or the electromagnetic actuator, the flap moves away from the valve inlet to allow the inlet gas to move from the valve inlet to the valve outlet.

A check valve can include a pressure actuator or an electromagnetic actuator. The check valve includes a valve inlet, a valve outlet, and flap disposed between the valve inlet and the valve outlet. The pressure actuator in fluid communication with the valve inlet. The check valve has an open state and a closed state. The check valve is configured to allow an input gas to flow from the valve inlet to the valve outlet when the check valve is in the open state. The check valve is configured to preclude the input gas from flowing from the valve inlet to the valve outlet when the check valve is in the closed state. Upon actuation of the pressure actuator or the electromagnetic actuator, the flap moves away from the valve inlet to allow the inlet gas to move from the valve inlet to the valve outlet.

The subject matter of the application is a device for adjustment and/or regulation of the CO.sub.2, carbon dioxide content of the inhaled air. Device based on the invention where a CO.sub.2 vessel 30 is connected to the CO.sub.2 input aperture 22, a measuring tool 15 determining the CO.sub.2 content of the exhaled air is connected to the exhaled air pipe 11, the output aperture of the measuring tool 15 is connected to the input aperture of a control unit 50, and the output aperture of the control unit 50 is connected to the valve 28 adjusting the blending rate of blending vessel 20 and so adjusting the CO.sub.2 content of the inhaled air.