Abstract: A nebulizer jet (10) having complementary portions (12 and 14) molded as a single part and joined by an integral hinge (16) for ease and precision of assembly. When the complementary portions are folded together about the hinge, they form a nebulizer chamber (22) with a jet inlet port (32), a liquid inlet tube (36), and an outlet port (34). A fractionating ball (40) is also molded integrally with the nebulizer jet, and is folded about another integral hinge (44) and secured in an operative position adjacent to the outlet port.

Abstract: A pneumatically powered oxygen pressure loss alarm system for use in conjunction with a gas anesthesia machine having an oxygen supply circuit and a gas mixing circuit. The oxygen pressure loss alarm system comprises a volume chamber in which a pressurized volume of oxygen is maintained, an oxygen escape valve for venting the chamber when pressure within the oxygen supply circuit falls below a critical minimum level, and an audible alarm operable in response to the flow of oxygen vented from the chamber through the oxygen escape valve. In addition, a reverse flow of residual gas from the gas mixing circuit, through a master valve also used to shut off the gas anesthesia machine, is coupled to the alarm to provide an audible indication of machine shut-down.

Abstract: An assembly of isolation valves (42, 44, 46) coupled to vaporizers (54, 56, 69), and a corresponding number of valve control levers (66, 68, 70) connected by an interlock mechanism that allows only one of the levers to be in an on position at any time. The interlock mechanism includes a cable (80, 81, 82) between each unique pair of control levers, the cables being only long enough to permit one lever of each unique pair to be moved to the on position. Each lever has a camming roller (66d, 68d, 70d) that engages and rotates a forked valve cam (86) to switch the valve on or off.

Abstract: A pop-off valve (92) having a significantly improved pressure-flow characteristic and resistance to vibration or "honking." The valve includes a poppet (154) having a flat bottom end wall exposed to pressure and a peripheral lip with a frusto-conical surface (158) for engagement with a valve seat 140. A vent-hole (196) in the poppet further enhances the vibration characteristics of the valve, and a dampening chamber (186) downstream of the poppet dampens any remaining vibrations.

Abstract: An improved overall arrangement is provided for resuscitators of the class adapted for administering substantially pure oxygen from a pressurized source thereof, and especially those of the kind functionally employing a demand responsive type oxygen supply valve in conjunction with a manually compressible squeeze bag. The demand type supply valve is mounted on and communicates with the end of the squeeze bag opposite from the end thereof on which the patient non-rebreathing valve (and the face mask associated with the latter) is mounted and communicates with the bag.

Abstract: A volume ventilator having a plurality of integrated modes of operation for providing a patient with a flow of breathing gas under pressure. A plurality of adjustable setting devices each producing an individual threshold signal related to a parameter of the gas flow. Mode switching means provides for the selection of at least one mode signal. Each threshold signal is compared with a common variable signal for producing a plurality of control signals. At least one of the control signals is selected in accordance with the selected mode signal and that control signal is applied to a valve system for controlling flow of gas to the patient. In this manner, the setting devices may be continuously adjusted to change one or more of the threshold signals without varying any of the other threshold signals. There is further provided a comprehensive system of alarms.

Abstract: In a pulmonary diagnostic instrument that includes a breath transducer for use in conjunction with the instrumentation for detecting respiratory functioning of a patient or specimen, the transducer comprises a flow tube in which is suspended for lineal displacement a partial diaphragm generally constructed as a foraminous plate, and which during testing, the specimen's breath flows therethrough to achieve some degree of displacement of said diaphragm. The diaphragm incorporates and operates in association with various ferrous rings for enhancing the transfer of magnetic lines of flux which are generated by a charged E-core for determining the extent of said lineal displacement which is representative of and can be interpreted to provide information pertaining to pulmonary functioning for diagnosis of the respiratory system of the specimen.

Abstract: In a vacuum pump, of the type being a single stage operative pump, a stator housing is provided and having rotatively mounted therein an eccentrically disposed rotor, which rotor is revolved by means of a motor, with the eccentric mounting of the rotor providing a point of contiguity between the rotor and the stator housing; a slot is provided approximate the location of the point of contiguity between the rotor and stator, and an oil reservoir supplies a quantity of oil to and through the slot to form a seal at this point of contiguity between the pump rotor and stator housing.

Abstract: A method and apparatus for initiating a positive-pressure-assisted inspiration phase in response to a patient's inspiratory effort, and independently of the absolute pressure at the time of the inspiratory effort, since the absolute pressure may vary from patient to patient or depend upon a particular mode of operation of the respiration system. The invention apparatus includes a differentiator circuit for obtaining a time-differentiated pressure signal, and a circuit for detecting a change in the sign of the slope of the differentiated signal. The patient's inspiratory effort is manifested as an increased rate of pressure drop, and this shows up as a change in the sign of the slope of the differentiated pressure, which is detected independently of absolute pressure, and is utilized to initiate an assisted inspiration phase.

Abstract: A method and appartus for determining patient lung pressure, compliance and resistance, for use in conjunction with a respirator system of the compensated-volume type wherein a predetermined volume of gas is delivered to the patient in each breathing cycle. The method and apparatus of the invention determine both the system pressure at the point of delivery to the patient and the patient lung pressure, both at the end of the inspiration phase of the breathing cycle, and utilize these values, together with a compensated volume signal, to compute the values of patient compliance and resistance. Control circuitry, actuated periodically or on demand, substitutes an enforced plateau period following inspiration, to allow the system pressure to fall to the value of lung pressure which is obtained at the end of the inspiration phase, thereby permitting the measurement of lung pressure by sampling system pressure at the end of the plateau period.

Abstract: An improved respirator gas delivery means of the type having a pneumatically-actuated piston slidably mounted in a cylinder, and separated therefrom by a resilient seal, such as a rolling seal or a bellows. An initial flow of air used to actuate the piston is established prior to delivery of a desired volume of breathable gas to a patient. The piston has a valve seal attached to its lower side, cooperating with a valve seat at an exit port in the cylinder, and tending to close the exit port under the weight of the piston. The initial flow of actuating air supports the piston at an equilibrium position allowing the flow to escape through exit port, and prestressing the resilient seal to minimize errors in the delivered volume. Closure of an external exit port valve halts the exit of actuating air, and allows the piston to move upwardly immediately in response to the continued admission of actuating air.

Abstract: Apparatus and a corresponding method for the protection of an ultrasonic transducer operating immersed in a liquid, such as in an ultrasonic nebulizer. Surface motion of the liquid is detected by analysis of the voltage across the transducer terminals, and this surface motion indication is combined with a transducer temperature indication to determine whether or not the transducer should be shut off to prevent destruction or damage due to overheating or absence of surrounding water. Once turned off, the transducer cannot be re-energized without the removal and reapplication of electrical power to the apparatus. Provision is made for allowing the transducer to remain on even when no surface motion is present, provided the temperature is below a certain value, to permit adjustment of the transducer circuit while the transducer is in operation. An alarm is actuated when the transducer is turned off to call attention to the high temperature or loss of surface motion.

Abstract: A method for determining the maximum and minimum lung pressure during the breathing cycle of a patient undergoing positive pressure breathing therapy by utilizing a respiration system which includes a console with a gas supply and control unit located at a substantial distance from the patient, and a transfer unit in proximity to the patient. The delivery hose from the transfer unit to the patient is very short and of relatively small volume, so that a pressure sensor located in the transfer unit can monitor the system pressure at a point which has a relatively low volume spacial separation from the patient's lungs.