Abstract: An apparatus and method for facilitating the respiration of a patient detects patient airway sounds and resolves these sounds into audio component bands whereupon an analysis is performed to produce a trend value. In response, a pressure action is determined using the trend value for controlling the pressure delivered to a patient for preventing the onset of obstructive apnea.

Abstract: The method of stabilizing a carbon dioxide sensor involves formulation of a bicarbonate buffer solution in the sensor with a bicarbonate ion concentration of from about 100 mM to about 200 mM bicarbonate. The method also involves treatment of the sensor to reduce the instability that may occur in carbon dioxide sensors when such sensors are exposed to either very low or very high carbon dioxide levels for extended periods of time. The sensor is treated by exposing the sensor to an aqueous solution containing at least 2 weight percent carbon dioxide, for from several days to several months. The solution may be prepared in advance, or may be dynamically infused with carbon dioxide to provide the desired carbon dioxide content.

Abstract: The configuration of its housing facilitates the assembly of a hybrid electrical optical connector plug in order to minimize manufacturing costs and thereby render the plug especially well suited for use with a disposable peripheral device. The housing consists of two snap-together housing halves that cradle the electrical and optical terminals in a properly aligned orientation and prevent their longitudinal as well as radial displacement.

Abstract: A humidifier (10) is provided which includes a body (16) defining a plenum (32) for receiving air and a quantity of water therewithin, said body (16) further presenting a tubular inlet (18) and a-tubular outlet (20), and a baffle (34) for directing the flow of air therethrough, said body (16) being integrally formed. A shelf (58) is provided adjacent the outlet (20) for minimizing the effect of waves generated by the flow of circulating air and inhibiting the discharge of water droplets through the outlet (20) which would otherwise be carried by the circulating air. The body (16) is preferably provided with a U-shaped sidewall (55) with the baffle (34) positioned between first and second sidewalls (36, 38) thereof so that the air introduced through the inlet (18) is directed in a U-shaped flow path to enhance humidification before it is exhausted through the outlet (20).

Abstract: A sensor element includes an analyte-permeable matrix which supports and maintains a sensing solution containing an analyte-sensitive indicator substance in a plurality of tiny vesicles. The sensor element is prepared by combining the sensing solution with an emuslifier that renders the solution dispersed within the matrix material. The sensing solution remains suspended in these dispersed vesicles after the matrix solidifies. A sensor element made in accordance with the present invention may be placed at the end of an optical fiber.

Abstract: The solution for storage and calibration of an intravascular blood sensor is an aqueous solution of from 10-35 mM of a first buffer component of bicarbonate, and at least one additional buffer component selected to maintain the pH of the solution substantially at or slightly below a neutral pH, and preferably below approximately pH 8. The first and additional buffering components preferably are selected to act in two separate pH regions with substantially no overlap of the buffering capacity of the different buffering components, and the concentration of the first buffer component in the solution is selected to permit a two point calibration of the intravascular multiparameter blood sensor by carbon dioxide and oxygen gas tonometry.

Abstract: The improved gas flow control apparatus controls the flow of multiple gases to a tonometer for calibration of a blood gas or pH sensor and compensates for the failure of gas supply solenoid valves to operate properly in controlling gas flow. Intermediate gas supply solenoid valves select between gas flow of the supplied gas in an open position, and venting to the atmosphere in a closed position. A common selector valve is also provided in the gas flow path to the tonometer to select gas flow from one of the intermediate gas flow valves. A control unit is provided for controlling the operation of the intermediate and common selector valves.

Abstract: The optical signal channel selector apparatus includes one or more first optical channels, and a plurality of a secondary optical channels for carrying an optical signal. A parabolic mirror is rotatable to provide optical communication between a first optical channel and any one of the secondary optical channels. A position encoded stepper motor is coupled to the parabolic mirror for controlling the position of the mirror. Solid state optical interface blocks having one or more filters receive the optical signal and transmit output optical signals with filtered wavelength ranges in the secondary optical channels. The rotation of the mirror by a position encoded stepper motor allows selection of a desired secondary channel, and automatically shutters the remaining channels closed.

Abstract: The method of stabilizing a carbon dioxide sensor involves treatment of the sensor to reduce the instability that may occur in carbon dioxide sensors when such sensors are exposed to either very low or very high carbon dioxide levels for extended periods of time. This is accomplished by storing the sensor in an aqueous solution containing at least 2 weight percent carbon dioxide, for from several days to several months. The solution may be prepared in advance, or may be dynamically infused with carbon dioxide to provide the desired carbon dioxide content.

Abstract: An improved chemical oxygen generator (10) includes an oxygen generating candle (12) having an oxygen source, which upon decomposition will yield oxygen, and a nontoxic additive to smooth decomposition and suppress formation of toxic free chlorine gas. The nontoxic additive may be taken from the group consisting of: (1) the oxides, hydroxides and carbonates of calcium and the rare earth elements; (2) the hydroxides and carbonates of magnesium; and (3) mixtures of the foregoing. A complete chemical oxygen generator utilizes the candle (12) of the invention. The oxygen generator preferably includes a canister (14), oxygen-generating candle (12), and an ignition device (16). Triggering of the ignition device ignites an ignition pellet (52) which initiates decomposition of the candle body (50). Once initiated, the candle will sustain decomposition to release breathable oxygen until the candle is completely reacted.

Abstract: A calibration cuvette apparatus for storing and calibrating a chemical sensor in a tonometered solution includes an upper cuvette section and a lower cylindrical valve section for alternately sealing the cuvette section and admitting a gas mixture to the cuvette section. The upper cuvette section has relatively narrow diameter upper and lower ends on either side of a wide diameter middle portion. The cuvette section is adapted to receive the sensor and retain the sensor in a fluid bath in the cuvette section so that the chemical sensor portion is disposed approximately in the center of the wide middle portion of the cuvette section. The chamber formed within the cuvette section is thus shaped so as to maintain the sensor in a position in the fluid bath so that any gas bubbles within the chamber will not dry the sensor. A lower end portion of the cuvette section includes a gas communication inlet for introducing gas into said chamber to equilibrate the tonometered buffer solution.

Abstract: The calibration cuvette apparatus for storing and calibrating a chemical sensor in a tonometered solution includes an upper cuvette section and a lower cylindrical valve section for alternately sealing the cuvette section and admitting a gas mixture to the cuvette section. The upper cuvette section has relatively narrow diameter upper and lower ends on either side of a wide diameter middle portion. The cuvette section is adapted to receive the sensor and retain the sensor in a fluid bath in the cuvette section so that the chemical sensor portion is disposed approximately in the center of the wide middle portion of the cuvette section. The chamber formed within the cuvette section is thus shaped so as to maintain the sensor in a position in the fluid bath so that any gas bubbles within the chamber will not dry the sensor. A lower end portion of the cuvette section includes a gas communication inlet for introducing gas into said chamber to equilibrate the tonometered buffer solution.

Abstract: A method for covalently bonding an analyte sensitive dye compound to an addition-cure silicone is disclosed. The method includes a first step of functionalizing the dye compound to provide a linker arm with an isolated multiple bond. A second step include hydrosilylating the functionalized dye with polymethylhydrosiloxane. The resulting compound is cross-linked with vinyl-terminated polysiloxane in a third and final step.

Abstract: The multiple optical fiber event sensor apparatus includes a semipermeable generally cylindrical shaft, one or more optical fiber gas sensor modules within the shaft, and an optical fiber pH sensor module extending beyond the distal end of the shaft, with the sensor modules arranged in an axially staggered relationship. The shaft contains a potting matrix for axially fixing the position of the optical fibers, and includes a gas permeable portion surrounding the one or more gas sensor modules, and a hydrophilic portion covering at least part of the pH sensor module. A hemodynamically shaped, rounded distal end is also provided on the distal end of the shaft. The device provides for a multiplicity of individual sensors incorporated in a single shaft which minimizes cross-interference and thrombus formation when used as an intravascular multi-sensor.

Abstract: The system and method for flow triggering pressure supported ventilation include a source of a predetermined, preinspiratory, constant flow of breathing gas to a patient, one or more flow sensors for measuring the rate of gas flow in a flow path communicating with the patient, means for determining when inhalation from the flow path has occurred, and means for generating pressure support in the delivered gas flow in response to inhalation by the patient, means to terminate pressure support when inspiratory phase concludes, and means to reestablish the predetermined, preinspiratory, continuous flow of breathing prior to the patient's next inspiratory effort. A plurality of individual gas sources preferably provide a controlled mixture of breathing gas. In combination with pressure support to the patient during the inspiration effort, the flow triggering strategy of the invention offers significant improvements in providing breath support to patients having weakened respiratory capabilities.

Abstract: The system for measuring the concentration of oxygen in a fluid sample which may also contain halothane includes a sensor having a matrix containing a first indicator dye which fluoresces at a known wavelength when irradiated with light of a specific wavelength and containing a second indicator dye which fluoresces at a different emission wavelength upon irradiation with light of a similar or different specific wavelength. The fluorescence of the first and second indicator dyes are quenched to a different degree by the presence of oxygen, but the fluorescence of the indicator dyes is quenched to the same degree by halothane. Means are provided for irradiating the indicator dyes in the matrix with the appropriate wavelengths of light, and means are provided for measuring the resultant intensity of fluorescence of the indicator dyes at the different wavelengths of fluorescence.

Abstract: A gating system is provided for controlling a ventilator means, which, in turn, generates a positive pressure breath. The systems including a sensing means for sensing sequential heart beats of a patient, together with a computing means, which is connected to the sensing means, for computing a period between the sequential heart beats. In addition to the above, a valve means is connected electrically to the computing means and pneumatically to the ventilator means for controlling the ventilator means, with the valve means being positioned to cease positive pressure breaths in response to the computer period.

Abstract: An apparatus and method for facilitating the respiration of a patient are disclosed which are particularly useful in treating mixed and obstructive sleep apnea and certain cardiovascular conditions, among others, by increasing nasal air pressure delivered to the patient's respiratory passages just prior to inhalation and by subsequently decreasing the pressure to ease exhalation effort. The preferred apparatus includes a patient-coupled gas delivery device for pressurizing the patient's nasal passages at a controllable pressure, and a controller coupled with the delivery device having a pressure transducer for monitoring the nasal pressure and a microcontroller for selectively controlling the nasal pressure. In operation, the controller determines a point in the patient breathing cycle just prior to inhalation and initiates an increase in nasal pressure at that point in order to stimulate normal inhalation, and subsequently lowers the nasal pressure to ease exhalation efforts.

Abstract: A hybrid electrical optical connector employing a push-pull plug receptacle combination. A hood structure protruding from the plug component of the connector simultaneously serves to ensure that the plug is properly rotationally oriented with respect to the receptacle prior to insertion, that the individual terminals are guided toward the respective terminal receiving channels, and that the plug is latched in place once fully engaged. A rigid armature allows the plug to be partially assembled and tested prior to final overmolding. In its final overmolded form the plug is impervious to the influx of contamination and can withstand a substantial amount of physical abuse. The inexpensive materials used in the construction of the plug and the ease of assembly yield a low cost plug well suited for use in conjunction with a disposable peripheral device.