Abstract: A compact and wearable metabolic analyzer transducer comprising a housing containing a plurality of analog sensors, an A/D converter, a microcontroller, and a power source operatively coupled thereto where the microcontroller is programmed to compute minute ventilation, O2 uptake, and CO2 production of a subject. The transducer and its contents are of a size and weight that can either be easily supported from a facemask worn by a subject or incorporated in a respiratory circuit. The measured values can be wirelessly transmitted or transmitted, via a cable, to a remote personal computer, a personal digital assistant (PDA), or other display devices such as digital watches or image projectors.

Abstract: A method for improving the performance of a galvanic fuel cell type oxygen sensor comprises providing a pressure equalization port leading to the interior of an inner core housing that contains the membrane, the electrolyte and the anode and cathode electrodes and hermetically sealing the sensor housing except for its sample inlet port and its sample outlet port. By connecting the same vacuum source to both the pressure equalization port and the sample outlet port, the device's membrane is less subject to movement or rupture as gas samples are drawn in via the sample inlet port. A technique for ensuring a hermetic seal is also described.

Abstract: A method for improving the performance of a galvanic fuel cell type oxygen sensor comprises providing a pressure equalization port leading to the interior of an inner core housing that contains the membrane, the electrolyte and the anode and cathode electrodes and hermetically sealing the sensor housing except for its sample inlet port and its sample outlet port. By connecting the same vacuum source to both the pressure equalization port and the sample outlet port, the device's membrane is less subject to movement or rupture as gas samples are drawn in via the sample inlet port. A technique for ensuring a hermetic seal is also described.

Abstract: A method of calibrating a metabolic analyzer incorporating an oxygen analyzer and a NDIR carbon dioxide analyzer in the field that does not require the use of gas cylinders containing gases of known concentration is described. In calibrating the CO2 detector, at the time of factory setup, the detector output for a gas of a known concentration is measured and stored in the memory of the metabolic analyzer's microprocessor, as is the detector output voltage when the IR source is dimmed by a known percentage. Subsequently, in the field, CO2 levels in ambient air and cell pressure are measured at two different flow rates through the sample chamber and the IR source is again dimmed by the same percentage as had been used at the time of factory setup. Based upon the resulting readings, both the zeroing and span adjustment factors can be computed.

Abstract: A compact and wearable metabolic analyzer transducer comprising a housing containing a plurality of analog sensors, an A/D converter, a microcontroller, and a power source operatively coupled thereto where the microcontroller is programmed to compute minute ventilation, O2 uptake, and CO2 production of a subject. The transducer and its contents are of a size and weight that can either be easily supported from a facemask worn by a subject or incorporated in a respiratory circuit. The measured values can be wirelessly transmitted or transmitted, via a cable, to a remote personal computer, a personal digital assistant (PDA), or other display devices such as digital watches or image projectors.

Abstract: A method of calibrating a metabolic analyzer incorporating an oxygen analyzer and a NDIR carbon dioxide analyzer in the field that does not require the use of gas cylinders containing gases of known concentration is described. In calibrating the CO2 detector, at the time of factory setup, the detector output for a gas of a known concentration is measured and stored in the memory of the metabolic analyzer's microprocessor, as is the detector output voltage when the IR source is dimmed by a known percentage. Subsequently, in the field, CO2 levels in ambient air and cell pressure are measured at two different flow rates through the sample chamber and the IR source is again dimmed by the same percentage as had been used at the time of factory setup. Based upon the resulting readings, both the zeroing and span adjustment factors can be computed.

Abstract: A device for directly measuring a person's respiratory exchange ratio (RER) utilizes a Zn-air battery cell and a constant current load circuit as an O2 pump capable of drawing oxygen from expired air. A thermistor located in the flow path forms a leg of a bridge circuit whose output is proportional to oxygen concentration in the expired air and, therefore, to oxygen uptake. The thermistor flowmeter circuit utilizes the thermal conductivity differences between O2 and CO2 to provide a measure at the relative ratio of the two gases present.

Abstract: A respiratory monitor apparatus comprises, in combination, a flexible mask fabricated from a stretchable fabric, such as spandex, that is designed to support a pneumotach flow measuring instrument in a way that does not require the instrument to be placed in the wearer's mouth, yet still remaining in fluid communication with the wearer's mouth and with little or no dead-space or leakage between the mask member and the wearer's face.

Abstract: A respiratory monitor apparatus comprises, in combination, a flexible mask fabricated from a stretchable fabric, such as spandex, that is designed to support a pneumotach flow measuring instrument in a way that does not require the instrument to be placed in the wearer's mouth, yet still remaining in fluid communication with the wearer's mouth and with little or no dead-space or leakage between the mask member and the wearer's face.