Abstract: A system is provided for detecting the breakthrough of CO.sub.2 into the inspiratory limb of a substantially closed circle patient breathing circuit having a CO.sub.2 absorber to remove CO.sub.2 from the continuously recirculating gases. The CO.sub.2 is detected by a gas analyzer located in the inspiratory limb of the patient breathing circuit. Upon detection of that CO.sub.2, the system increases the flow of fresh gas into the circle patient breathing circuit to a flow rate in excess of the minute volume of gas being delivered at that time to the patient. The increased flow of fresh gas basically prevents the further flow of CO.sub.2 from the expiratory limb into the inspiratory limb, thus preventing the CO.sub.2 from being inhaled by the patient.

Abstract: A Raman gas analysis system uses a half-wave plate to match the polarization of Raman scattered light emitted from a gas analysis cell to a preferred polarization orientation of a diffraction grating. The gas analysis system includes a plasma discharge tube for generating a polarized light beam; a gas analysis cell for containing a sample gas which produces Raman scattered light in response to being irradiated with the polarized light beam; an optical subsystem for collecting and providing the Raman scattered light with a preferred polarization orientation; a holographic diffraction grating for dispersing the Raman scattered light into component light signals; and an array detector for detecting the component light signals.

Abstract: A medical device includes a hollow needle for piercing the skin of a patient. Prior to use, the needle is located in a needle protected position within a housing. The needle can be moved outwardly from the needle protected position to an extended position where it is ready for use with the patient. After use, the needle is retracted back into the housing to the needle protected position. A door is positioned at the distal end of the housing and has an aperture. The door is slidable between a first position where the needle is in alignment with the aperture in the door so that the needle can pass through the aperture to be moved to its extended position and a second position where the needle does not line up with the aperture and thus the needle cannot be moved from the needle protected position to the needle extended position.

Abstract: An algorithm is disclosed that enables the display for a medical ventilator to automatically adjust its wave characteristics depending on the settings for that ventilator established by the clinician. As the respiratory rate, or rate at which the ventilator provides breaths to the patient, is changed by the user, the rate of sweep of the waveform generator displaying that data is also changed to insure that the data is displayed in the most relevant manner. As another parameter, as the pressure limit in the patient circuit is set by the clinician, the waveform vertical scale is adjusted to make sure the particular limit of pressure is displayed. As the pressure limit or the respiratory rate are changed in the ventilator by the clinician, the waveform of he data displayed also is automatically modified to make that data best presentable to the clinician.

Abstract: An anesthetic vaporizer having a means of mixing the anesthetic agent with a relatively low flow of carrier gas or a larger amount of carrier gas. A valve is operable by the user to select between the high flow anesthesia where the carrier gas and anesthetic agent are mixed in a mixing chamber and the low flow anesthesia where the carrier gas and anesthetic agent are diverted directly into the patient circuit. Accordingly, the anesthetic vaporizer is usable for high flow anesthesia, however, when used for low flow, the diverted flow allows more rapid response by eliminating the large volume of the mixing chamber.

Abstract: An improved system for the determining the collapse of a bellows within a canister as part of a ventilator system for delivering breaths to a patient via a patient circuit. The system measures the pressure in the bellows canister external of the bellows and measures the pressure within the interior of the bellow. A processor compares the pressures and determines when the pressure within the canister exceeds a predetermined offset in excess of the pressure within the interior of the bellows to conclude that the bellows is in a collapsed condition. In the preferred embodiment, the processor also uses, as input data, the flow delivered by the ventilator to the bellows canister to determine that offset value. When a bellows empty condition is determined, various actions can be taken, among them to signal an alarm and also to change various functions of the ventilator to prevent further difficulties in the overall system.

Abstract: A system of making a connection between the yoke of an anesthetic delivery apparatus and a gas cylinder for supplying a gas to that apparatus. The system includes an adaptor block that has a keying system, such as pegs, that keys the adapter block into a specific gas cylinder, such as by indentations. The adapter block has machine readable indicia and is affixed to the anaesthesia delivery apparatus such that the apparatus can read the indicia to determine the position of the adaptor block and thus identify the particular gas cylinder that is connected to the adapter block. By this system, a plurality of gas cylinders having differing gases can be used to supply a single inlet of an anesthetic delivery apparatus rather than have a separate inlet for each gas. In each instance, the particular gas thus provided is identified by the anaesthetic delivery apparatus to make the necessary adjustments to that apparatus to administer the gas to a patient.

Abstract: An anaesthetic vaporizer for supplying an anaesthetic to a patient and having an inlet for receiving carrier gas and an outlet for delivering carrier gas laden with the anaesthetic to the patient. The vaporizer includes a pump having an expandable body, preferably of a metal, and which expands to draw in the liquid anaesthetic from a reservoir through a valving mechanism and which collapses to meter a precise amount of that liquid anaesthetic into a chamber where it is vaporized for introduction into the carrier gas as it passes between the inlet and the outlet.

Abstract: A method for manufacturing a heat-sealed neo-natal medical monitoring probe requires a pair of light sources and a light detector to be placed between two layers or conformable material used to implement the probe. The layers are designed to be self-aligning when placed in the assembly press for heat-sealing the perimeter of the probe. The heat-sealing process both protects the light sources and detector from fluids and also functions to precisely position and secure these devices.

Abstract: The menu selection device uses a combination of the rotary position of a rotary optical encoder and the operation of a coaxially mounted push-button switch to enable the user to progress through various layers of a hierarchical menu system. The rotary position of the shaft translates to a menu category which is selected by the user activating the push-button switch. The selection of the menu category allows the user to then sequence through the plurality of menu entries within this menu category by again rotating the shaft. The user selects one of these menu entries by again activating the push-button switch.

Abstract: A tilt mechanism for use with an infant care apparatus such as an incubator to place and retain the infant care apparatus in a desired tilt angle. The tilt mechanism includes two sets of crossed links, each set forming an X between the links. One end of each link is rotatable affixed to a fixed base and the other end rotatably affixed to the infant care apparatus. A locking device is used that allows the infant apparatus to be manually moved by means of the crossed link sets to the desired angle and then locked into that position. With this mechanism, the entire infant apparatus is tilted rather than only some internal bed or infant platform.

Abstract: This invention pertains to methods for preparing 5-aroyl-1,2-dihydro-3H-pyrrolo-[1,2-a]pyrrole-1-carboxylic acids represented by formula (I): ##STR1## In a first embodiment, the method comprises the sequential steps of cyclizing, via a free radical ring closure reaction, and hydrolyzing a compound represented by formula (IV): ##STR2## wherein R.sub.1 is lower alkyl.

Abstract: A container (2) for a liquid anaesthetic agent for supplying the agent to an anaesthetic vaporiser comprises a reservoir for the liquid agent, a valve (6) which, when closed, prevents the flow of the liquid agent from the reservoir, a tubular outlet (10) through which the liquid can leave the reservoir when the valve is open. An O-ring (20) at the free end of the conduit provides a sealing surface for forming a seal with a corresponding sealing surface provided at an inlet to a vaporiser to which the anaesthetic agent is to be supplied. A flange (22) engages a guide on the vaporiser, to retain the container in contact with the vaporiser.

Abstract: A heated humidifier for an infant incubator wherein the water in the water reservoir is heated by an active heater located above the surface of the water and a heat exchanger that transfers heat from the active heater and which extends downwardly to a point beneath the water surface to heat the water. In the preferred embodiment, the heat exchanger is an extruded member in the shape of an I-beam to transfer the heat from an electric heater above the surface of the water to heat the volume of water in the reservoir to create water vapor.

Abstract: A system for allowing a user to disable an apnea alarm in an anesthesia system when the anesthesia ventilator is in the mechanical ventilation mode. The system takes advantage of the redundancy of both a CO2 monitor and a volume monitor triggering the apnea alarm based upon a predetermined fault condition. The inventive system allows the user to disable the apnea alarm based upon a signal from the volume monitor to alleviate the problem of spurious alarm signals from the volume monitor. The attempt to disable the volume monitor fault signal to the apnea alarm is prevented, however, without a system check by a CPU to insure that the CO2 monitor is, in fact, fully operational and capable of sending its fault signal to the apnea alarm to trigger that alarm. The system continuously checks the CO2 monitor and immediately restores the viability of the volume monitor as a trigger for the apnea alarm at any time the CO2 monitor becomes disabled and is unable to trigger the apnea alarm itself.

Abstract: A mechanism for aligning the elements of an optical system is disclosed. One aspect of the present invention is an alignment mechanism which includes lead screws placed on opposite corners of the elements to be aligned. The elements are provided with threaded holes of different pitch, and the lead screw is provided with threads of the same unequal pitches as the elements, thereby forming a differential lead screw. The threads include a locking thread which assures a positive lock between the lead screw and the elements to be aligned and eliminates backlash between them. Another aspect of the present invention is an interference fit mechanism which is provided by the employment of a slightly-oversized flexible boss which mates with a cavity. The boss is provided with a thin outer wall capable of flexing when the boss is inserted into the cavity. Yet another aspect of the present invention includes a wobble plate comprising a spherical socket and housing.

Abstract: An anesthetic vaporizer is disclosed having an inlet for receiving carrier gas and an outlet for delivering carrier gas with an anesthetic agent to a patient. The vaporizer has a passage that extends between the inlet and the outlet, a vaporizing chamber and a passageway extending from the vaporizing chamber to the outlet. A means such as a differential pressure transducer monitors the differences in pressure between the carrier gas in the passage and the anesthetic agent in the passageway to control the flow of the anesthetic agent through the passageway.

Abstract: This apparatus makes use of the existing data collection probe connector on the instrumentation as the port through which the software updates are loaded into the programmable memory devices that are used to store the operational software of the instrumentation. Circuitry is provided in the instrumentation to automatically differentiate between software update data being loaded into the instrumentation and the normal monitoring data that is received from the probe. This is accomplished by the use of probe defining circuitry that is able to differentiate between the standard probe used for data collection purposes and the software update probe that is provided to download software into the programmable memory devices.

Abstract: A nitric oxide delivery system that is useable with any of a variety of gas delivery systems that provide breathing gas to a patient. The system detects the flow of gas delivered from the gas delivery system at various times and calculates the flow of a stream of nitric oxide in a diluent gas from a gas control valve. The flow of gas from the gas delivery system and the flow established from the flow control valve create a mixture having the desired concentration of nitric oxide for the patient.The system does not have to interrogate the particular gas delivery system being used but is an independent system that can be used with various flows, flow profiles and the like from gas delivery systems.