Abstract: A method of detecting disconnect of a patient circuit of a ventilation system, wherein a circuit disconnect is detected with a first sensitivity and a second sensitivity. The circuit disconnect detected with the first sensitivity is performed by detecting a volume loss for a minimum period of time, detecting a peak pressure loss for at least two consecutive breathing cycles or a minimum period of time, and detecting a pressure loss continuing for a predetermined period of time. The circuit disconnect detected with the second sensitivity is performed by detecting a volume loss for a single breathing cycle, detecting a pressure loss for a single breathing cycle, and detecting an increase of compliance. The first sensitivity is lower than the second sensitivity. Preferably, an alarm is activated when the circuit disconnect is detected with the first sensitivity, and subsystems of the ventilation system is informed of the circuit disconnect that has been detected with the second sensitivity.

Abstract: A ventilator device and system comprising a rotating compressor, preferably a drag compressor, which, at the beginning of each inspiratory ventilation phase, is accelerated to a sufficient speed to deliver the desired inspiratory gas flow, and is subsequently stopped or decelerated to a basal flow level to permit the expiratory ventilation phase to occur. The ventilator device is small and light weight enough to be utilized in portable applications. The ventilator device is power efficient enough to operate for extended periods of time on internal or external batteries. Also provided is an oxygen blending apparatus which utilizes solenoid valves having specific orifice sizes for blending desired amounts of oxygen into the inspiratory gas flow. Also provided is an exhalation valve having an exhalation flow transducer which incorporates a radio frequency data base to provide an attendant controller with specific calibration information for the exhalation flow transducer.

Abstract: A ventilator, device and system comprising a rotating compressor, preferably a drag compressor, which, at the beginning of each inspiratory ventilation phase, is accelerated to a sufficient speed to deliver the desired inspiratory gas flow, and is subsequently stopped or decelerated to a basal flow level to permit the expiratory ventilation phase to occur. The ventilator device is small and light weight enough to be utilized in portable applications. The ventilator device is power efficient enough to operate for extended periods of time on internal or external batteries. Also provided is an oxygen blending apparatus which utilizes solenoid valves having specific orifice sizes for blending desired amounts of oxygen into the inspiratory gas flow. Also provided is an exhalation valve having an exhalation flow transducer which incorporates a radio frequency data base to provide an attendant controller with specific calibration information for the exhalation flow transducer.

Abstract: A ventilator device and system comprising a rotating compressor, preferably a drag compressor, which, at the beginning of each inspiratory ventilation phase, is accelerated to a sufficient speed to deliver the desired inspiratory gas flow, and is subsequently stopped or decelerated to a basal flow level to permit the expiratory ventilation phase to occur. The ventilator device is small and light weight enough to be utilized in portable applications. The ventilator device is power efficient enough to operate for extended periods of time on internal or external batteries. Also provided is an oxygen blending apparatus which utilizes solenoid valves having specific orifice sizes for blending desired amounts of oxygen into the inspiratory gas flow. Also provided is an exhalation valve having an exhalation flow transducer which incorporates a radio frequency data base to provide an attendant controller with specific calibration information for the exhalation flow transducer.

Abstract: A catheter having a tube and a tip connected to one end of the tube. The tip has a collar, an end member and lowered side walls positioned between the collar and the end member. The lowered side walls define an opening that is biased toward the end member.

Abstract: A ventilator device and system comprising a rotating compressor, preferably a drag compressor, which, at the beginning of each inspiratory ventilation phase, is accelerated to a sufficient speed to deliver the desired inspiratory gas flow, and is subsequently stopped or decelerated to a basal flow level to permit the expiratory ventilation phase to occur. The ventilator device is small and light weight enough to be utilized in portable applications. The ventilator device is power efficient enough to operate for extended periods of time on internal or external batteries. Also provided is an oxygen blending apparatus which utilizes solenoid valves having specific orifice sizes for blending desired amounts of oxygen into the inspiratory gas flow. Also provided is an exhalation valve having an exhalation flow transducer which incorporates a radio frequency data base to provide an attendant controller with specific calibration information for the exhalation flow transducer.

Abstract: An air-to-air heat exchanger for pre-cooling and humidifying a breathing gas supplied to a patient. The air-to-air heat exchanger is made of low specific heat material and has an elongate conduit, a plurality of interior fins and a plurality of exterior fins. The elongate conduit is installed adjacent the output of an inspiratory lumen, through which a breathing gas is supplied to a patient. The interior fins extend from an inner surface toward a central axis of the elongate conduit, while the exterior fins extend radially outwardly from an outer surface of the elongate shell.

Abstract: A ventilator device and system comprising a rotating compressor, preferably a drag compressor, which, at the beginning of each inspiratory ventilation phase, is accelerated to a sufficient speed to deliver the desired inspiratory gas flow, and is subsequently stopped or decelerated to a basal flow level to permit the expiratory ventilation phase to occur. The ventilator device is small and light weight enough to be utilized in portable applications. The ventilator device is power efficient enough to operate for extended periods of time on internal or external batteries. Also provided is an oxygen blending apparatus which utilizes solenoid valves having specific orifice sizes for blending desired amounts of oxygen into the inspiratory gas flow. Also provided is an exhalation valve having an exhalation flow transducer which incorporates a radio frequency data base to provide an attendant controller with specific calibration information for the exhalation flow transducer.

Abstract: A ventilator device and system comprising a rotating compressor, preferably a drag compressor, which, at the beginning of each inspiratory ventilation phase, is accelerated to a sufficient speed to deliver the desired inspiratory gas flow, and is subsequently stopped or decelerated to a basal flow level to permit the expiratory ventilation phase to occur. The ventilator device is small and light weight enough to be utilized in portable applications. The ventilator device is power efficient enough to operate for extended periods of time on internal or external batteries. Also provided is an oxygen blending apparatus which utilizes solenoid valves having specific orifice sizes for blending desired amounts of oxygen into the inspiratory gas flow. Also provided is an exhalation valve having an exhalation flow transducer which incorporates a radio frequency data base to provide an attendant controller with specific calibration information for the exhalation flow transducer.

Abstract: A ventilator device and system comprising a rotating compressor, preferably a drag compressor, which, at the beginning of each inspiratory ventilation phase, is accelerated to a sufficient speed to deliver the desired inspiratory gas flow, and is subsequently stopped or decelerated to a basal flow level to permit the expiratory ventilation phase to occur. The ventilator device is small and light weight enough to be utilized in portable applications. The ventilator device is power efficient enough to operate for extended periods of time on internal or external batteries. Also provided is an oxygen blending apparatus which utilizes solenoid valves having specific orifice sizes for blending desired amounts of oxygen into the inspiratory gas flow. Also provided is an exhalation valve having an exhalation flow transducer which incorporates a radio frequency data base to provide an attendant controller with specific calibration information for the exhalation flow transducer.

Abstract: A medical ventilator having a valve which controls the flow of gas from a pressurized gas source to a patient for inhalation. Flow through the valve is choked and pressure upstream of the valve is held stable so that a known relationship exists between the position of the valve and the flow rate through the valve. An open loop control system causes the valve to open or close as needed to deliver a preselected tidal volume of gas to the patient on each breath. Since the flow rate is known, no feedback to the controller regarding actual flow conditions is required. The exact positioning of the valve and length of time that the valve is to be held open is predetermined by the controller before the breath is delivered, and is repeated for subsequent breaths. Preferably, the valve is driven by a stepping motor, and the controller comprises a microcomputer.

Abstract: A medical ventilator having a valve which controls the flow of gas from a pressurized gas source to a patient for inhalation. Flow through the valve is choked and pressure upstream of the valve is held stable so that a known relationship exists between the position of the valve and the flow rate through the valve. An open loop control system causes the valve to open or close as needed to deliver a preselected tidal volume of gas to the patient on each breath. Since the flow rate is known, no feedback to the controller regarding actual flow conditions is required. The exact positioning of the valve and length of time that the valve is to be held open is predetermined by the controller before the breath is delivered, and is repeated for subsequent breaths. Preferably, the valve is driven by a stepping motor, and the controller comprises a microcomputer.

Abstract: A valve in a medical ventilator opens and closes as is needed to permit venting of respiratory gases from a patient to the atmosphere. Changes in position of the valve are caused by a stepper motor, which is joined to the valve by a mechanical linkage. The stepper motor, in turn, is powered by electronic signals from a microcomputer controller. The position of the valve is controlled on a closed loop basis by the controller, which receives feedback regarding the pressure of the proximal gases from a pressure transducer. The valve is uniquely designed to enable the controller to cause the valve to open quickly once the patient begins to exhale, and to permit accurate control over the proximal pressure as the valve is approaching the closed position. In particular, the valve comprises a poppet and a valve seat which have curved mating surfaces, with the curved surface on the poppet being truncated so that pressure gain variance is minimized over the range of positions of the poppet relative to the valve seat.

Abstract: A gas blender for use with home ventilation equipment where pressurized oxygen is mixed with ambient air, in which a double ended poppet cooperates with two valve seats which are configured and orientated so that axial motion of the double ended poppet simultaneously opens both valves to maintain a constant flow ratio, or simultaneously closes both valves to maintain a constant flow ratio. One of the valve seats may be adjustably positioned to determine the initial flow ratio of gases through the valve seats.

Abstract: An apparatus for detecting fluid flow by obtaining a differential pressure across an obstruction in a fluid conveying channel. The obstruction is hingably connected to the housing of the channel. The connection is of a width substantially less than the periphery of the channel so as to reduce the collection of contaminants which decrease the accuracy of the apparatus. Because the orifice defined by the area between the obstruction and the periphery of the channel is variable according to the fluid flow, the pressure differential versus flowrate relationship is different from the square-law relationship of a fixed orifice, and provides a relatively high pressure differential at low flowrates and a relatively low pressure differential at high flowrates.

Abstract: A ventilator for providing artificial respiration to a patient has a plurality of pneumatic components mounted on a manifold. The manifold is a one piece aluminum casting having a base with ducts formed therein to permit fluid communication between the pneumatic components. The ducts are exposed on the underside of the base and are removably sealed from the atmosphere by a gasket and sealing plate which are secured to the underside of the base so as to cover the exposed portion of the ducts. Several components are formed in the manifold as part of the casting, including an accumulator and pulsation dampener, both of which are gas storage chambers. A plurality of fins are also formed as part of the manifold, and act as a heat sink for a printed circuit board which is secured to the manifold. Removable pneumatic components are secured to mounting blocks which extend upwardly from the base and have threaded bores therein for the receipt of threaded fasteners.