Abstract: A fluidization level sensor and controller for use in a fluidized patient support surface has a controller coupled to a sensor and a compressor. The patient support surface contains a mass of granular particles housed in frame walls and supported by a diffuser. The compressor forces a fluid, typically air, into a plenum chamber and through the diffuser. The fluid flows through the mass of granular particles, causing the mass of granular particles to fluidize, and exits through a fluid permeable sheet. The fluidization level sensor produces an output signal proportional to the fluidization level of the mass of granular particles, and provides this output signal to the controller. The controller generates a compressor control signal in response to the output of fluidization level sensor, which in turn adjusts the compressor to maintain a substantially constant fluidization level.

Abstract: The disclosure relates to a device for determining perfusion capacity in a region of a patient's skin and underlying tissue utilizing a thermoelectric device to create a temperature differential, a sensor for measuring the temperature differential, a controller coupled to the sensor and the thermoelectric device for maintaining the temperature differential substantially constant by providing electrical energy to the thermoelectric device, and measuring the electrical energy provided to the thermoelectric device when the thermoelectric device is positioned adjacent the region of the patient's skin to indicate perfusion capacity.

Abstract: A fluidization level sensor and controller for use in a fluidized patient support surface has a controller coupled to a sensor and a compressor. The patient support surface contains a mass of granular particles housed in frame walls and supported by a diffuser. The compressor forces a fluid, typically air, into a plenum chamber and through the diffuser. The fluid flows through the mass of granular particles, causing the mass of granular particles to fluidize, and exits through a fluid permeable sheet. The fluidization level sensor produces an output signal proportional to the fluidization level of the mass of granular particles, and provides this output signal to the controller. The controller generates a compressor control signal in response to the output of fluidization level sensor, which in turn adjusts the compressor to maintain a substantially constant fluidization level.

Abstract: A fluidization level sensor and controller for use in a fluidized patient support surface has a controller coupled to a sensor and a compressor. The patient support surface contains a mass of granular particles housed in frame walls and supported by a diffuser. The compressor forces a fluid, typically air, into a plenum chamber and through the diffuser. The fluid flows through the mass of granular particles, causing the mass of granular particles to fluidize, and exits through a fluid permeable sheet. The fluidization level sensor produces an output signal proportional to the fluidization level of the mass of granular particles, and provides this output signal to the controller. The controller generates a compressor control signal in response to the output of fluidization level sensor, which in turn adjusts the compressor to maintain a substantially constant fluidization level.

Abstract: An apparatus for evaluating perfusion adjacent a skin surface includes a housing having first an second interior regions. The housing is configured to engage the skin surface. The apparatus also includes a plunger located in the first region of the housing for applying pressure to a first zone of the skin surface, a vacuum connection coupled to the second region of the housing to permit suction to be applied to the second region of the housing and to a second zone of the skin surface, a first temperature sensor for generating an output signal related to the temperature of the first zone of the skin surface, a second temperature sensor for generating an output signal related to the temperature of the second zone of the skin surface, and a processor circuit coupled to the first and second temperature sensors for determining a differential temperature between the first and second zones of the skin surface to provide an indication of perfusion adjacent the skin surface.

Abstract: An optical transmitter (200) in a cable television system (100) includes an uncooled laser diode (250) and a thermal compensation circuit (FIG. 2). The thermal compensation circuit includes a voltage controlled attenuator (220) located between the transmitter input (205), at which an electrical information signal is received, and the laser diode (250). The thermal compensation circuit also includes a thermistor (230) that is situated physically near the laser diode (250) and that is characterized by a resistance that varies with temperature. The thermistor (230) is coupled to a controller (225) for sensing thermistor resistance changes, which are indicative of changes in the laser diode temperature, and for selectively controlling the attenuator (220) to attenuate the level of the electrical information signal.

Abstract: An apparatus for evaluating perfusion adjacent a skin surface includes a housing having first and second interior regions. The housing is configured to engage the skin surface. The apparatus also includes a plunger located in the first region of the housing for applying pressure to a first zone of the skin surface, a vacuum connection coupled to the second region of the housing to permit suction to be applied to the second region of the housing and to a second zone of the skin surface, a first temperature sensor for generating an output signal related to the temperature of the first zone of the skin surface, a second temperature sensor for generating an output signal related to the temperature of the second zone of the skin surface, and a processor circuit coupled to the first and second temperature sensors for determining a differential temperature between the first and second zones of the skin surface to provide an indication of perfusion adjacent the skin surface.

Abstract: An apparatus is provided which supports a patient on an inflatable structure. The inflatable structure preferably has two components: a) lower inflatable layer which is selectively operable to provide basic support for the patient and which includes a plurality of laterally offset zone which may be independently inflatable to control rotation of the patient. Further, a second inflatable layer includes a plurality of zones for establishing optimal patient interface pressures and patient comfort levels, and may also include sufficiently independent inner chambers to facilitate the providing of specific therapies such as alternation of primary pressure contact areas, or percussion or vibration of the patient through inner cell inflation.

Abstract: An apparatus and method for evaluating perfusion adjacent a skin surface includes the steps of measuring a reference rate of perfusion of the skin surface, storing the reference rate of perfusion, and applying a positive force to the skin surface. The apparatus and method also includes the steps of measuring a second rate of perfusion adjacent the skin surface after the positive force is applied, and calculating a differential rate of perfusion between the reference rate of perfusion and the second rate of perfusion after positive force is applied to provide an indication of perfusion adjacent the skin surface. The apparatus and method further includes the step of displaying the indication of perfusion.

Abstract: An apparatus is provided which supports a patient on an inflatable structure. The inflatable structure preferably has two components: a) lower inflatable layer which is selectively operable to provide basic support for the patient and which includes a plurality of laterally offset zone which may be independently inflatable to control rotation of the patient. Further, a second inflatable layer includes a plurality of zones for establishing optimal patient interface pressures and patient comfort levels, and may also include sufficiently independent inner chambers to facilitate the providing of specific therapies such as alternation of primary pressure contact areas, or percussion or vibration of the patient through inner cell inflation.

Abstract: A proportional flow control valve is provided for use with low air loss patient support systems. The valve includes a valve housing having an inlet and an outlet defined therein with a valve passage defined through the housing between the inlet and outlet. A chamber is defined in the housing, the chamber further including a nipple cavity defined in the bottom thereof and a cam stop extending from the bottom into the chamber. A valve spool is rotatably disposed within the chamber. The valve spool includes an alignment nipple fitting into the nipple cavity and a cam defined on the bottom thereof through a predetermined rotational arc. The cam and cam stop cooperate to limit the rotational arc of the valve spool within the chamber. A proportional flow control groove is defined in the valve spool. The flow control groove establishes linear air flow through the valve depending on the angular displacement of the spool within the chamber.