Intermountain Health Care

Other

Frederick L Farr

Justin S Clark

William D Wallace

Christopher A Cutler

Method and apparatus for gas-liquid equilibration (tonometry) in a transportable vessel. Specifically the method and device is concerned with tonometry of blood or buffer solution in a syringe. The compartment formed when a syringe plunger is partially inserted into a syringe barrel serves as a tonometer chamber where gas of known composition is bubbled through a liquid sample. Gas enters the chamber through small holes in the tip of the syringe plunger and bubbles upward through the sample. The syringe plunger itself is a second chamber which is used for heating and humidifying the gas prior to entering the tonometer chamber. The entire syringe is housed in a temperature controlled environment during equilibration. This environment allows observation of the entire tonometry process. After equilibration the syringe tonometer is easily removed from the heat controlled environment and is used as the sample's transport vessel. The syringe configuration allows easy entry of the sample into the target sytem, e.g. a blood gas analyzer.

Method and apparatus for equilibrating gas and liquid in a transportable

Method and system for sampling and determining chemical substances such as blood gases, in a fluid matrix, such as blood, by bringing the chemical substances into equilibrium with a liquid in a fiber probe, passing the equilibrated liquid to a sensor adjacent the equilibrium region and on into a hollow fiber line enclosed in a calibration chamber. Calibration of the sensors is accomplished by reversing the flow of liquid from the hollow fiber line to the sensors. In the system chemical substances for sensor calibration are provided by an electric proportioner whose output is continuously controlled by the output of the sensors such that the substances proportioned into a fluid in the calibration chamber surrounding the hollow fiber line are substantially the same as the substances within the matrix. The concentration of substances is determined by the output of the sensors and the amount of substances fed from the proportioner to the fluid surrounding the hollow fiber line. When the substances being measured are in equilibrium with both the matrix and fluid surrounding the hollow fiber line, a null response is obtained at the sensors.

Sampling and determination of diffusible chemical substances

An alveolar gas sampling system comprises a catheter adapted for placement in a patient's nostril or in an endotracheal tube and connected to a positive displacement pump through a three way valve. Signal means for detecting onset of inspiration and expiration is mounted at the tip of the catheter and connected to a controller. The positive displacement pump is driven by a reversible stepper motor actuated by the controller during the flow of alveolar air. When the desired amount of alveolar gas has been sampled, the stepper motor is reversed and the position of the valve is switched by the controller causing the alveolar gas collected in the positive displacement pump to be expelled for analysis.

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Salt Lake City, UT, United States of America

Frederick L Farr