Gas sampling catheter assembly and method
First Claim
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1. A catheter for sampling gases in vivo comprising:
- a hollow generally flexible gas-impermeable tube having a leading end at least a portion of which is adapted to be inserted into the body of a patient;
a gas-permeable membrane traversing the entire length of the insertable portion of the tube;
means at the leading end of the tube for communicating the hollow of the tube and the inside of the gas-permeable membrane; and
a gas-impervious barrier means circumscribing the tube between the tube and membrane behind the communicating means to prevent gas transfer to the leading end from membrane behind the barrier.
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Abstract
A catheter assembly for sampling gases in biological tissue in vivo, including a catheter constructed of a hollow tube sheathed in a gas-permeable membrane, and an impermeable barrier between the tube and membrane to define the boundary of a sampling tip. A catheter hub slideably surmounts the catheter and detachably receives a calibration chamber normally surrounding the sampling tip. The method includes purging the calibration chamber with a calibration gas and thereafter removing the calibration chamber and inserting the catheter into the tissue to be sampled.
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Citations
12 Claims
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1. A catheter for sampling gases in vivo comprising:
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a hollow generally flexible gas-impermeable tube having a leading end at least a portion of which is adapted to be inserted into the body of a patient; a gas-permeable membrane traversing the entire length of the insertable portion of the tube; means at the leading end of the tube for communicating the hollow of the tube and the inside of the gas-permeable membrane; and a gas-impervious barrier means circumscribing the tube between the tube and membrane behind the communicating means to prevent gas transfer to the leading end from membrane behind the barrier.
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2. A catheter assembly for sampling gases in vivo comprising:
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a hollow gas-impermeable tube terminating in a tip insertable into the body of a patient; a gas-permeable membrane circumscribing the tip and the entire insertable portion of the tube; communication means associated with the insertable tip and providing communication between the inside of the insertable tip and the gas-permeable membrane; a gas-impervious barrier means interposed between the membrane and the tube adjacent the tip; a catheter hub, slideably surmounting the tube and membrane normally situated rearward of the tip, the hub comprising coupling means; and a diametrally enlarged calibration chamber removably mounted upon the coupling means and surrounding the catheter tip, the calibration chamber having a port for admitting calibration gases into the space around the catheter tip confined by the calibration chamber. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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9. A catheter assembly for sampling gases comprising:
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an elongated tube comprising an exterior gas-permeable membrane, the leading end of the tube comprising a sampling tip; means communicating the inside of the sampling tip with the gas-permeable membrane; a calibration chamber having an internal diameter which is greater than the external diameter of the sampling tip, the calibration chamber removably surrounding the sampling tip; and means mounted upon the calibration chamber for communicating calibration gas to the interior of the calibration chamber thereby immersing the sampling tip in calibration gas having a known gas composition. - View Dependent Claims (10)
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11. A method of sampling gases comprising the steps of:
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obtaining a gas sampling tube and covering the tube with a gas-permeable membrane, the tube having an opening at the tip thereof which opening is exposed to the membrane; providing a gas-impervious barrier between the tube and membrane near the tip of the tube so as to define a sampling tip of predetermined length; surrounding the sampling tip with a removable calibration chamber; admitting a predetermined gas into the calibration chamber around the sampling tip to accommodate calibration of the catheter prior to in vivo sampling; and thereafter situating the catheter adjacent tissue to be sampled. - View Dependent Claims (12)
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Specification