Nihon Kohden Corporation

Kabushiki Kaisha Toshiba

Muneshige Kurahashi

Shinji Yamamori

Naoki Kato

Ichiro Ogura

Kaoru Machida

Kota Saeki

Sakari Yokoyama

Yoshihiko Sugiyama

Tadayuki Ishihara

A dehumidifier is connected to a respiratory gas measuring apparatus. A membrane dryer has a first flow path through which a respiratory gas of a subject passes, and a second flow path through which a purge gas passes. A first normally-closed electromagnetic valve is disposed in a first upstream flow path that communicates with the first flow path. A second normally-closed electromagnetic valve is disposed in a first downstream flow path that communicates with the first flow path. A third normally-closed electromagnetic valve is disposed in a second upstream flow path that communicates with the second flow path. A fourth normally-closed electromagnetic valve is disposed in a second downstream flow path that communicates with the second flow path.

Dehumidifier

A two-wavelength type respiratory gas concentration measuring device includes a connector tube which is held in the mouth of an examinee and which has airtight windows, a light source which applies infrared rays through the windows of the connector tube, and first and second filters. The first filter allows the transmission of a light component whose wavelength is such that it is absorbed by the respiratory gas, and the second filter allows the transmission of a light component whose wavelength is such that it is not absorbed by the respiratory gas. A photodetector converts the infrared rays transmitted through the filters into an electric signal. A first detector receives the electric signal and detects the light output of the first filter. A second detector receives the electric signal and detects the light output of the second filter. A power computing circuit performs a power computation of the output of the second detector with a power exponent m. A divider circuit divides the output of the first detector by the output of the first power computing circuit. A DC level detector detects the DC level of the photodetector when no infrared rays are applied. A second power computing circuit performs a power computation of the output of the DC-level detector with a power exponent of 2(m-1). A multiplier circuit multiplies the output of the second power computing circuit by the output of the divider.

Two-wavelength type respiratory gas concentration measuring apparatus

A method of and apparatus for effecting artificial respiration in synchronism with a patient's voluntary breathing. The apparatus is in the form of an external body ventilator with an assistor, and comprises a jacket, a suction pump, a suction pipe, a changeover device, a jaw movement detection device, and a changeover controlling device. The jacket has a rigid shell for surrounding the chest of a patient and forming an air-tight chamber between the chest and the rigid shell when the jacket is applied to the chest of the patient. The suction pipe is in fluid communication with the air-tight chamber of the jacket, and the changeover device is for effecting a changeover between releasing the air in the air-tight chamber through the suction pipe and into the atmosphere during voluntary respiration, and connecting the suction pipe to the suction pump during artificial respiration. The jaw movement detection device produces a signal corresponding to the movement of the jaw of the patient, and the changeover control device determines a timing of voluntary breathing by the patient on the basis of a signal detected by the jaw movement detection device, and controls the changeover device on the basis of the timing.

Method of and apparatus for artificial respiration in synchronism with

A measuring conduit adapted for flow rate and concentration of a fluid for use in a measuring apparatus which measures both the flow rate of the fluid such as a respiratory gas containing a particular gas component, for example, carbon dioxide, using an ultrasonic wave and the concentration of the particular gas component in an optical manner. In order to simultaneously measure the flow rate and concentration and also to reduce the dead space of the measuring conduit, this measuring conduit comprises a single conduit member through which the fluid flows; a pair of ultrasonic transducers attached to the conduit member so as to face each other along a line slanted with respect to a flow direction of the fluid; and a pair of light transmitting windows airtightly provided in the wall of the conduit member between the ultrasonic transducers so as to face each other. One of the light transmitting windows introduces a light beam from an external light source into the conduit member. The other light transmitting window introduces the light penetrating the fluid flowing through the conduit member into a photo detecting element of the measuring apparatus.

Measuring conduit for flow rate and concentration of fluid

A respiratory gas concentration measuring apparatus includes a chopper having a first filter for passing therethrough light from a light source and having a first wavelength which can be absorbed by a gas to be measured and a second filter for passing therethrough light from the light source and having a second wavelength which cannot be absorbed by the gas. The chopper is rotatable to position the first and second filters alternately in a light path. The light having passed through the filters is converted by a photodetector into an electric signal. A first detector detects an output from the first filter based on the electric signal, and a second detector detects an output from the second filter based on the electric signal. The apparatus has a power computing circuit for raising an output from said second detector to an mth power, m being a power exponent preset in the power computing circuit, and a divider circuit for dividing an output from the first detector by an output from the power computing circuit. The power exponent m is the ratio between a temperature-dependent coefficient .theta..sub.1 of the output of the first detector which varies exponentially with a temperature variation and a temperature-dependent coefficient .theta..sub.2 of the output of the second detector which varies exponentially with a temperature variation.

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Tokorozawa, Japan

Muneshige Kurahashi