Abstract: A system for automatically refilling the patient breathing circuit of an anesthesia system wherein the system detects the existence of a large leak in the patient breathing system and reduces the flow of the fresh gas to the patient circuit to minimize the amount of gas that is vented to the atmosphere. As the leak is corrected, the system automatically detects that the leak has been alleviated and increases the fresh gas flow to a high flow to refill the patient breathing circuit in a rapid time. Upon refill, the system detects that the circuit and the system has been refilled and automatically reduces the fresh gas flow back to a lower level desired by the clinician to maintain the anesthesia. The fresh gas flow used to refill the patient circuit is the same composition of gases and anesthetic agent as initially set by the clinician.

Abstract: This apparatus places the laser diode light source in the connector affixed to the distal end of the cable, proximate to the patient. The disposable portion of the probe simply consists of the apparatus required to affix the probe to the patient's appendage and the mating portion of the connector that interconnects with the cable. The disposable portion of the probe can be a minimalistic design since all the expensive elements are located in the medical monitoring instrument or the cable connector.

Abstract: An improved method and apparatus for the photoplethysmographic monitoring of blood analyte parameters, specifically oxyhemoglobin, deoxyhemoglobin (reduced hemoglobin), carboxyhemoglobin and methemoglobin, uses a plurality of beams of light having different spectral contents to trans-illuminate the tissue of a patient. Received light is measured and the normalized differential absorption is used in a forward calibration equation to generate estimated relative blood analyte concentration values. Error in the blood analyte concentration values is minimized by applying constraints to the estimated analytes. Specifically, the constraints require that all relative analyte concentration values are greater than or equal to zero and sum to one hundred percent.

Abstract: An audible waveform system is provided that senses a parameter relating to the ventilation of a patient. The system produces short bursts of sound of a predetermined frequency as the changes occur in that parameter based on certain increments of change. The bursts themselves are preferable at a frequency that is the same for equal pressures but increases and decreases in frequency as the parameter increases or decreases, respectively. In the preferred embodiment, the system provides an audible waveform based on the pressure in the patient airway so that the clinician can receive information relating to that waveform conveniently and without taking attention away from other monitors and/or alarms.

Abstract: The present invention is directed to a charge coupled device in which, during the shifting interval, the charge storage pixels are biased with an electrical potential greater than the absolute value of the CCD inversion potential and, during the charge integration interval, the charge storage pixels are biased with an electrical potential that is less than the CCD inversion potential. In this manner, the present invention substantially reduces error attributable to impact ionization or dark current.

Abstract: A stopcock comprises a hollow barrel which receives in a rotatable manner a co-operating tap. A section of the tap is formed with holes which allow communication between selected hollow spigots extending from the barrel. A further section of the tap of larger diameter than the section is formed with indents which engage with detents formed on a large diameter section of the barrel to provide a positive indication when the tap is rotated within the hollow barrel to one or more selected positions.

Abstract: The present invention is directed to an oximeter sensor that may be employed with a variety of oximeter processing and display units. The oximeter sensor includes a plurality of radiation emitting devices that are capable of providing a spectral content that is useful in the correlation of a number of different oximeter processing and display units. The oximeter sensor further includes a plurality of resistors, with each resistor being connected to a different oximeter processing and display unit to permit the particular oximeter processing and display unit to select an appropriate correlation curve.

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: A respiratory gas monitor for measuring the concentration of certain gases in a respiratory gas stream has a compact and unitary lid assembly having an integral low-profile motor and a cylindrical infrared light beam chopper. The lid assembly also contains a motor position sensor and flex circuit for passing electrical signals through epoxy sealed orifices in the lid to a processing and control unit in the monitor. The flexible circuit uses releasable connectors to facilitate removal of the monitor from an external controller and the removal of the lid assembly from the bottom portion of the monitor.

Abstract: The present invention provides an oximeter sensor holder that includes first and second lateral members for receiving the sensor, a living hinge connecting proximal ends of the first and second lateral members, and first and second press tabs for moving the first and second lateral members about the living hinge. The first lateral member and the first press tab are in an opposed and spaced-apart relationship to the second lateral member and second press tab, respectively. To open and close the lateral members, at least one of the press tabs pivots about the living hinge away from and toward the other press tab. The holder can include one or more retaining walls to inhibit lateral movement of the sensor when positioned between the first and second lateral members.

Abstract: An infant incubator having a base and a hood positioned atop of the base to form an infant compartment therebetween. The hood has a front access door that is hinged so as to move between an open and a closed position. The edge of the door opposite the hinged part has a magnetic strip that mates with a strip of magnetically attractable material positioned on the edge of the hood opening such that the door is retained in its closed position by a magnetic force. At least one door handle is mounted to the door at or near the end of the magnetic strip at the top of the door and can be pulled to open the door. The door is sufficiently flexible that pulling the handle causes a peeling effect such that relatively little force need be exerted to open the door from the corner, yet considerable force is required to open the door from inside the incubator by an infant residing therein.

Abstract: Efficient management of breathing gases and anesthesia is achieved in an anesthesia delivery system which incorporates a flow minimization routine. The breathing circuit is provided with a pop-off valve and a flow sensor for detecting the pop-off flow. The flow rate of fresh gas into the breathing circuit is controlled, preferably via a digital computer, to minimize the amount of gas exhausted from the circuit. A control routine determines the minimal fresh gas flow necessary to maintain appropriate oxygen concentration, anesthetic agent concentration pop-off flow. A minimum value for the fresh gas flow may also be input to the control system. A fresh gas flow boost routine provides quick responses to charges in the user-set oxygen and agent concentrations. A circuit fill routine provides fresh gas to fill the breathing circuit until pop-off flow is sensed.

Abstract: A heat flux sensor is used in conjunction with a patient sensor, such as a patient temperature sensor, and which is secured to the patient in close proximity to the patient sensor. The heat flux sensor monitors the heat flux between the patient and the environment. Upon dislodgement of the patient probe, the heat flux sensor senses a change in heat flux that is of a predetermined amount and provides a signal indicating that the patient probe has become partially or fully dislodged from the patient. In the case of a patient heat sensor, the use of a heat flux sensor provides a quicker and larger signal than would be seen by merely monitoring the change in temperature due to partial or full probe dislodgement.

Abstract: An infrared spectrometer for anesthetic gas monitoring using an infrared light source is divided into two separately sealed sections. A partition wall separating the two sections contains a partition window allowing infrared light to pass from the infrared source into a sealed sample chamber. In case of a failure of the sealed sample chamber the gas does not come into contact with the infrared source, thereby minmizing the risk of possible explosion. A gasket of neoprene or butyl rubber is used to seal the two sections from one another. The signal produced by the spectrometer indicating the composition of the sample gas is monitored to alert the user of a single point failure at the seal of the sample chamber.

Abstract: The integrated multimode optical coupling apparatus comprises an N-to-M optical coupling arrangement that is simple to manufacture, minimizes optical losses and is significantly less expensive than the prior art arrangements of coupling optical signals. The preferred embodiment of the apparatus of the present invention comprises a substrate into which is formed a plurality of optical channels, each of which is joined at one end into a single output optical channel. This integrated optical coupler is formed by diffusing silver ions or other equivalent ions into the glass substrate in these defined areas to form channels of high optical refractive index in the body of the substrate. At one end of each of the optical channels that are formed in the substrate, the plurality of the optical channels are joined together in a volumetric region of the substrate wherein the individual channels merge into one unified common structure.

Abstract: Noise content in the output signal of a system using time division multiplexing (TDM) is measured to determine whether the output signal represents a reliable measurement. A "dark" channel in a TDM input signal may be used to isolate noise which is present in the input signal from desired informational content in the signal. The noise is processed to determine if any component of the noise will be "imaged" into the passband of the system. Any such components are then processed in a manner approximating the system transfer function to produce a noise signal indicative of the noise content of the system output signal. In one embodiment of the invention, the noise signal is used to remove noise from the output signal of the system.

Abstract: The system of the preferred embodiment of the invention contains a processor as well as a permanently mounted programmable FLASH memory in which the firmware resides. The system makes use of a socket in which a memory device can be installed. The socket accepts a firmware update memory device which has stored thereon the firmware revisions or replacement firmware. Once the firmware update memory device is installed, the processor downloads the instructions contained therein to the permanent FLASH memory device. Once the program is transferred to the permanent memory, the system operation is not dependent on the reliability of the socket. In addition, program changes can be input to the system without requiring that the system be equipped with a data input/output device, such as a modem, floppy disk drive or the like.

Abstract: A control system where the clinician can have manual control of the state for various alarms, generally volume alarms and apnea alarms. The control is interactive, that is, while the clinician can manually set the state in a variety of settings, the control system automatically overrides the clinician's selection to activate both the volume and apnea alarms wherever the mechanical ventilator is turned on. In addition, there is another override where a breath is detected by the ventilator to turn all of the alarm systems from both being inactive to both alarms being active.

Abstract: A connection, preferably for use in a medical environment, for joining a rigid circular port from a medical machine to an elastomeric hose cuff having a medical hose extending therefrom. The rigid cuff has an external annular bead formed at its outward end while the elastomeric hose cuff has an internal annular bead formed at its distal end. When the components are coupled together by sliding the hose cuff over the rigid port, a double seal is formed between the various annular beads and the surfaces of the component to provide a substantially leakproof seal between the elastomeric hose cuff and the rigid port to prevent gasses from escaping to the surrounding environment.

Abstract: A system for continuing the monitoring of certain gases delivered to a patient during the administration of nitric oxide to provide therapy to the patient. The nitric oxide is controlled by a electrically operated valve that is operated by means of an electrical signal from a CPU. At times when the various gas monitors are being calibrated, the normal alarms based upon those gas monitors are conventionally disabled during that calibration time. With the present invention, the electrical signal to the electrically operated valve is detected at the time the system goes into a calibration cycle and that detected electrical signal is used to establish limits such as a upper limit and a lower limit. Therefore, when the electrical signal to the valve is thereafter monitored and its value exceeds either of those limits, the overall nitric oxide delivery system will activate an alarm to alert the user of an abnormal condition.