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Sumitomo Electric Industries, Limited

Bunji Hagihara

Isao Isshiki

Kenichi Yoshida

Kikuo Nomura

Tamotsu Fukai

A transcutaneous blood oxygen measuring device is disclosed for the noninvasive measurement of oxygen partial pressure in arterial blood which includes a cathode surrounded by an anode held together by an insulating plastic in an electrode part, a heating portion to heat the skin of a subject to which the device is applied and to receive the electrodes plus an electrolyte. The heating portion has an opening to indirectly expose the electrodes, via an electrolyte and associated membrane, to the subject's skin surface. Adjacent the working surfaces of each electrode an electrolyte is provided, retained by an oxygen permeable membrane which, in turn, is brought into contact with the subject's skin. The working face of one electrode, typically the cathode, is extended beyond the plane of the working face of the other electrode; the opening in the heater is smoothly rounded and the cathode plus tapered hole, both having approximately the same cross-sectional area, are placed in close proximity with each other.

Transcutaneous blood oxygen measuring device

A polarographic electrode assembly for transcutaneous measurement of partial oxygen pressure in arterial blood comprising an anode, a cathode which has a thin ring surface or a circularly-bounded field of dot-shaped surfaces and an insulating electrode holder, a disposable tubular member holder fixedly holding the periphery of an oxygen permeable hydrophobic electrode membrane, and a skin-heating part including heat-conducting block which is thermally connected to a heater and a temperature detector. The heat-conducting block has a thick peripheral portion and thin disk-shaped inner portion having a through-hole to expose the cathode surface to the subject's skin via the membrane. One side of the heat-conducting block has a smooth surface to be applied on skin, and the back side has a receiving space for the membrane holder. The heat-conducting block embraces the membrane holder which embraces the anode and cathode portion of the electrode part in such a manner that the membrane covers the working surfaces of the anode and cathode via an electrolyte layer. In a prefabrication step the membrane is strongly bonded in a uniformly stretched condition to the holder for stability of sensitivity of the electrode. By using such a cathode a good correlation coefficient of measured PO.sub.2 over actual arterial PO.sub.2 and a good S/N ratio are provided, and by using a skin heating block having a sufficient heating area a highly stable electrode sensitivity is assured.

Oxygen measuring electrode assembly

An oxygen measuring electrode assembly for measuring an oxygen partial pressure in arterial blood in which a cylindrical anode and cathode are disposed coaxially in an insulator in such way that the former is placed in the latter. The end surfaces of said electrodes contact with the body surface via an electrode membrane which covers said electrodes with a suitable tension and holds an electrolyte solution layer on said electrode surfaces. Said electrode membrane is fixed on an annular end portion of a cylindrical holder of an electrically and thermally insulating material which surrounds said anode. A metal collar surrounding said holder bears a membrane-covering metal plate which has an opening through which an area of said electrode membrane is exposed to the body surface. Said membrane cover plate, which is connected to said collar and controlled to keep a desired temperature, heats said body surface and activates the blood capillary, that is arterializes the subcutaneous tissue. Thus the electrode can detect the arterial oxygen partial pressure.

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Suita, Japan

Bunji Hagihara