| 摘要 |
1,044,987. Physiological measuring; catheters. BECKMAN INSTRUMENTS Inc. June 26,1964 [July 19, 1963], No. 26454/64. Heading A5K and A5R. [Also in Division G1] An arrangement for making in vivo measurements in a body fluid comprises a pair of spaced electrodes joined by an electrolyte, shielded from the fluid to be investigated by a membrane permeable to the constituent to be measured, the sensor being positioned in one end of an elongated flexible tube or catheter through which the electrical connection is established by a concentric cable. The cathode 18 which may be a platinum wire is surrounded by a glass sleeve 20 through which it extends and terminates in an exposed surface which is flush with the surface of the glass. The anode 22, which may be of silver, covers the glass tube in such a manner as to leave an annular space enclosed by a membrane 28 for containing the electrolyte. The apparatus is said to be useful for determining the oxygen content of blood, polyethylene, P.V.C.,tetrafluoroethylene and polypropylene being suggested for the membrane and sodium and potassium chloride solutions for the electrolyte. The membrane is clamped between a frusto-conical end 32 of a sleeve 30 and a conical section 34 on the anode. A phosphor bronze pin 36 to which the cathode is connected engages a conical surface 74 of a conducting member 72 in which the centre conductor 78 of coaxial cable 76 is terminated. Blood may be sampled simultaneously with making measurements in arteries veins etc. by allowing it to pass into annular chamber 110 through aperture 108, a channel leading from the chamber to the end of the catheter outside the body being provided. The catheter is provided with a coupling member for connection to an instrument which measures the blood pressure & c. Alternative arrange - ments using oxygen-reduction electrodes for measuring chloride and quinone-quinhydrone and pH electrodes for determining by the alteration of pH the dissolved CO 2 are referred to, and the detection of hydrogen by reversing the polarity of the electrodes is described. |
