Patents by Inventor Justin S. Clark

Justin S. Clark has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6766191
    Abstract: The hematocrit of blood (i.e., the percentage of whole blood volume occupied by red blood cells) perfusing a finger is determined by stimulating the finger with two current frequencies, one relatively high (e.g., 10 MHZ) and the other relatively low (e.g., 100 KHz). Voltages induced in the finger in response to the two current frequencies are then captured and separated into baseline and pulsatile components. The hematocrit is determined as a function of the ratio of the high frequency pulsatile component to the low frequency pulsatile component, multiplied by the ratio of the square of the low frequency baseline component to the square of the high frequency baseline component. The volume of blood perfusing the body part at which hematocrit is to be measured may be increased on each pulse by the application of external pressure to the finger, such as by applying a pressure cuff to the finger. Assemblages including two pairs of electrodes are used to effect the determination of hematocrit.
    Type: Grant
    Filed: May 16, 2000
    Date of Patent: July 20, 2004
    Assignee: Microcor, Inc.
    Inventors: Robert Gail Billings, Justin S. Clark, Jon Neese
  • Patent number: 6128518
    Abstract: The hematocrit of blood (i.e., the percentage of whole blood volume occupied by red blood cells) perfusing a finger is determined by stimulating the finger with two current frequencies, one relatively high (e.g., 10 MHZ) and the other relatively low (e.g., 100 KHz). Voltages induced in the finger in response to the two current frequencies are then captured and separated into baseline and pulsatile components. The hematocrit is determined as a function of the ratio of the high frequency pulsatile component to the low frequency pulsatile component, multiplied by the ratio of the square of the low frequency baseline component to the square of the high frequency baseline component. The signal-to-noise ratio of the captured voltages can be enhanced by the application of external pressure to the finger, such as by applying a pressure cuff to the finger.
    Type: Grant
    Filed: July 23, 1998
    Date of Patent: October 3, 2000
    Assignee: Microcor, Inc.
    Inventors: Robert Gail Billings, Justin S. Clark, Ke-shieng Yang, Jon Neese, Allan L. Kaminsky
  • Patent number: 5423322
    Abstract: A system and method for automatically and noninvasively monitoring the blood pressure of a subject. The volume changes of an artery, such as a digital artery or the temporal artery, are detected by a photoplethysmograph. The volume changes are then used to determine the blood pressure and the blood pressure waveform, of the subject. The model used to relate the volume of the artery to the pressure contained within the artery is referred to as the total compliance model. The total compliance model determines the compliance of each patient's artery which is being used as a sensing site. The compliance information is then used to determine the blood pressure at any particular point in time to the detected volume of the artery.
    Type: Grant
    Filed: April 14, 1994
    Date of Patent: June 13, 1995
    Assignee: Medical Physics, Inc.
    Inventors: Justin S. Clark, Shuxing Sun
  • Patent number: 5111817
    Abstract: A noninvasive system and method for monitoring arterial oxygen saturation levels which may also be used to continuously and noninvasively monitor blood pressure, including generating a continuous blood pressure waveform. The apparatus of the described embodiment includes a red LED and an infrared LED which are positioned to direct their respective light beams into, or reflected by a patient's body part. A phototransducer device is positioned to receive the light beams which are transmitted through the body part. A pressure cuff surrounds the body part and the LEDs. During calibration periods, pressure is applied to the body part and the systolic and mean blood pressures are determined and the arterial oxygen saturation level in the body part is determined.
    Type: Grant
    Filed: December 29, 1988
    Date of Patent: May 12, 1992
    Assignee: Medical Physics, Inc.
    Inventors: Justin S. Clark, William D. Wallace
  • Patent number: 4847493
    Abstract: Apparatus and method are provided for calibrating a mass spectrometer. The calibration hardware includes a relatively small, relatively low pressurized tank for containing calibration gas. The calibration gas tank is preferably located inside the same housing that contains the ion source assembly and the analyzing section of the mass spectrometer. Each of the calibration gas and sample gas, whose components are to be determined, communicates with its own associated valve. These two valves control the flow of a selected one of the sample gas and the calibration gas to the ion source assembly. The calibration gas valve has an extremely low leakage rate and can be controlled to permit the passage of very low flow rates of calibration gas, which can be of benefit in checking the linearity associated with the ion source assembly pressure. For each calibration procedure, very small amounts of calibration gas are utilized, in a range around 10.sup.-5 STD cc.
    Type: Grant
    Filed: October 9, 1987
    Date of Patent: July 11, 1989
    Assignee: Masstron, Inc.
    Inventors: Ingvar E. Sodal, Ronald R. Bowman, Jerritt Hansell, Justin S. Clark, Michael J. Criddle
  • Patent number: 4424276
    Abstract: Method and apparatus for determining the gaseous content of a diluent, such as determining the oxygen or carbon dioxide content of blood. A sample of the diluent whose gaseous content is to be measured is anaerobically pumped past a junction tee after being placed in a reservoir. A second diluent, not part of the sample, is equilibrated with a gas (not the gas to be measured) in a first tonometer. This second equilibrated diluent is pumped past the junction tee where it is mixed with the diluent sample. The gas in the second diluent is selectively chosen to drive the gas to be measured into the dissolved phase. The diluent mixture is then allowed to flow through an appropriate sensor that senses the presence of the gas to be measured. This first measurement is stored in a suitable controller, such as a microprocessor.
    Type: Grant
    Filed: December 7, 1981
    Date of Patent: January 3, 1984
    Assignee: Intermountain Health Care
    Inventors: Justin S. Clark, Ming-Cheng Yen
  • Patent number: 4363327
    Abstract: A non-invasive cyclic injection method for determining pulmonary blood flow, the ventilation-perfusion distribution and functional residual capacity, which consists of the non-invasive cyclical introduction of soluble and insoluble inert gases into the airstream of the human patient, each period of introduction followed by a similar period free from the introduction of soluble inert gases to allow for the washout of their concentrated buildup in the venous system. Sampling and analysis of expired air during all parts of the cyclic injection and non-injection of gases takes place with the results being electronically obtained and translated into digital data indicative of the parameter being determined.
    Type: Grant
    Filed: August 22, 1980
    Date of Patent: December 14, 1982
    Assignee: Intermountain Health Care
    Inventor: Justin S. Clark
  • Patent number: 4256461
    Abstract: 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.
    Type: Grant
    Filed: May 17, 1979
    Date of Patent: March 17, 1981
    Inventors: William D. Wallace, Christopher A. Cutler, Justin S. Clark, Frederick L. Farr
  • Patent number: 4221224
    Abstract: A non-airtight method for determining alveolar ventilation, oxygen uptake and carbon dioxide production which comprises introducing a known amount of an inert gas into the airway of a patient during inspiration and monitoring the expired gas until a steady state is reached wherein the volume of inert gas inhaled is equal to the amount exhaled and subsequently monitoring the expired air containing a known volume of inert gas for inert gas, carbon dioxide and oxygen concentrations.
    Type: Grant
    Filed: June 29, 1978
    Date of Patent: September 9, 1980
    Assignees: Intermountain Health Care, Primary Children's Medical Center
    Inventor: Justin S. Clark
  • Patent number: 4221567
    Abstract: 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.
    Type: Grant
    Filed: December 23, 1977
    Date of Patent: September 9, 1980
    Assignee: Intermountain Health Care
    Inventors: Justin S. Clark, William D. Wallace, Frederick L. Farr
  • Patent number: 4220162
    Abstract: 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.
    Type: Grant
    Filed: November 24, 1978
    Date of Patent: September 2, 1980
    Assignee: Intermountain Health Care
    Inventors: Justin S. Clark, Frederick L. Farr
  • Patent number: 4109505
    Abstract: A system for automatically withdrawing blood from a patient and testing various parameters of the blood, such as oxygen saturation, hemoglobin, gas content (PO.sub.2, PCO.sub.2) and pH, includes a withdrawal unit which automatically withdraws a measured volume of blood, and returns all of it to the patient except a small measured quantity which is provided to an analysis unit that measures the gas content and pH. The withdrawal unit includes provision for continuously monitoring patients' blood pressure, irrigation from a standard I.V. source between blood withdrawals, or a constant low flush of saline, alternatively, as well as detection of any air in the blood, which results in shutting down the system and activating an air alarm. The withdrawal unit also has provision for automatically withdrawing a small sample of blood, measuring oxygen content, and returning all blood to the patient, all on a programmed basis.
    Type: Grant
    Filed: April 7, 1975
    Date of Patent: August 29, 1978
    Assignee: Primary Children's Hospital
    Inventors: Justin S. Clark, Lloyd G. Veasy
  • Patent number: 4062373
    Abstract: A method of accurately mixing gases in desired proportions which comprises establishing the gases to be mixed at a uniform pressure; sequentially feeding the gases through a common restrictor for proportionate time periods to give the gas mix desired. The apparatus used includes a pressurizing gas reservoir unit which adjusts all gases to be mixed to have a common pressure; electronically actuated rapid response fluidic interface valves; a common restrictor through which the gases are passed to a receiving and mixing chamber; and timing means controlling the valves to allow gases to be sequentially passed therethrough for pre-set time periods.
    Type: Grant
    Filed: April 25, 1977
    Date of Patent: December 13, 1977
    Inventors: Justin S. Clark, Wm. Dean Wallace
  • Patent number: 4019523
    Abstract: A method of accurately mixing gases in desired proportions which comprises establishing the gases to be mixed at a uniform pressure; sequentially feeding the gases through a common restrictor for proportionate time periods to give the gas mix desired.
    Type: Grant
    Filed: February 7, 1975
    Date of Patent: April 26, 1977
    Inventors: Justin S. Clark, Wm. Dean Wallace