Liquid injector for wetting mechanically delivered intrapulmonary gases having a reservoir adapted to contain a quantity of liquid. A tube extends downwardly into the reservoir to a level below the level of the liquid in the reservoir. A one-way check valve controls the flow of liquid from the tube. Tubing including an additional one-way check valve is provided for delivering gas under pressure to the reservoir above the liquid in the reservoir to apply pressure to the liquid in the reservoir to force the liquid up through the tube. An orifice is provided which is in communication with the first named one-way check valve means. A body is provided forming a chamber surrounding the orifice. A valve is provided for adjusting the flow of liquid from the orifice. Gas under pressure is supplied to the chamber to cause the gas to come in contact with the liquid passing through the orifice means. Gas is withdrawn from the chamber after liquid has been introduced into the gas.

An arrangement for connecting a patient to a respirator (1) comprising a humidifier (8) for humidifying gas inspired by the patient. The arrangement also comprises a moisture-heat-exchanger (10) whose one side is connected to the respirator inlet and outlet (2,3) and whose other side is connected to the patient such that inspired gases pass the humidifier (8) before reaching the patient and expired gases do not pass the humidifier.

A flow probe for use in a humidification system is disclosed. The flow probe is adapted to be positioned in a humidified gases flow (for example oxygen or anesthetic gases) such as that which is provided to a patient in a hospital environment. The flow probe is designed to provide both temperature and flow rate sensing of the gases flow by incorporating two sensors (preferably thermistors) and the shape and alignment of the probe enables accurate readings by reducing the occurrence of condensation on the sensors. A number of possible applications are disclosed wherein the flow sensor is included in humidification control systems which provide a patient with a desired humidity level or simplify the amount of user input required or wherein the flow sensor provides a controller with flow information which may then be used to determine certain, possibly dangerous, conditions (such as incorrect flow sensor placement, breathing circuit disconnected, no water in the humidification chamber or humidity out of required limits).

A constant flow and controlled-ventilation pulmotor responsive to the respiration pressure in the respiratory circuit of a patient in which the intervention of a processor causes visually observable information to be presented to the operator to allow immediate control of mechanical ventilation and the adaptation of same to the clinical requirements of the patient. First, second and third desired pressure, time and flow rate parameters are set by a control board. A maximum pressure-responsive valve is responsive to the first pressure, time, and flow rate parameters, a minimum pressure-responsive valve is responsive to the second pressure, time, and flow rate parameters, and a solenoid valve is responsive to third pressure, time, and flow rate parameters. A transducer continuously detects in real time the value of the instantaneous pressure in the respiratory circuit of the patent and supplies an electrical signal indicative thereof to the processor. The processor processes the signals from the transducer and the control board and respectively visualizes them on a video display as breathing waveforms and as numerals representative of the first, second, and third sets of parameters.

Breathing circuits for medical respiratory devices which have an inspiratory conduit for delivery of respiration-related aeriform substances to a patient, may also have a expiratory conduit, and, in any case are arranged to communicate with a patient interface, such as a wye (14), and have heating means for respiration-related aeriform substances in at least the inspiratory conduit. The heating means may be a heated-liquid heating tube (11) within at least the inspiratory conduit or an electrical heating wire (38) on or in an inspiratory conduit comprising respiratory hose (37). The tube is in circulatory relationship with a heated-liquid reservoir (13) and is arranged internally to contain heated liquid (30) from the reservoir, and to transfer heat from the liquid--by radiation and conduction from the tube wall--to the substances in the conduit. This transferred heat tends to inhibit or to control formation of dangerous aqueous condensate from the substances by compensating heat losses they otherwise sustain, enhancing their capacity to retain water vapor and providing an intra-conduit environment in which the condensate is unlikely to form. A manifold (12) enables the tube to extend to the expiratory conduit.