Abstract A transcutaneous probe for causing oxygen and other gases or vapors carried in the bloodstream of a mammal to be extracted from the blood through the skin and passed to a device, such as a mass spectrometer, for analyzing the extracted gas. The probe has a boundary wall intended to be placed in contact with the skin comprising a first layer of gas permeable material and a second layer of perforate or porous gas-impermeable material in intimate contact with the first, the size and distribution of the perforations or pores in the second layer being such that the wall has a substantially uniform extrinsic macropermeability which is significantly lower than the inherent permeability of the first layer alone and such that in use, gas passes into the perforations or pores of the second layer from respective volumes of tissue which do not substantially overlap.
A transcutaneous probe for measuring gas concentration in arterial blood including a body defining a gas collecting chamber, one wall portion of said chamber defined by a porous member and a composite membrane supported thereby, said composite membrane having a first layer constituted by a gas-permeable plastics film and a second layer constituted by a perforated metal film, the size and distribution of the perforations in the perforated metal film being such that the wall has a substantially uniform extrinsic macropermeability which is significantly lower than the inherent permeability of the first layer alone and that in use, gas passes into the perforations of said second layer from respective volumes of tissue which do not substantially overlap, each perforation in the perforated metal film having a frustoconical form, and the gas permeable plastics film being in intimate contact with the face of the perforated metal film which bears the smaller diameter ends of said perforations to prevent the first and second layers from separating from each other.
Claim 2
Dependent Claim
167 words
A transcutaneous probe for measuring gas concentration in arterial blood including a body defining a gas collecting chamber, one wall portion of said chamber defined by a porous member and a composite membrane supported thereby, said composite membrane having a first layer constituted by a gas-permeable plastics film and a second layer constituted by a perforated metal film, the size and distribution of the perforations in the perforated metal film being such that the wall has a substantially uniform extrinsic macropermeability which is significantly lower than the inherent permeability of the first layer alone and that in use, gas passes into the perforations of said second layer from respective volumes of tissue which do not substantially overlap, each perforation in the perforated metal film having a frustoconical form, and the gas permeable plastics film being in intimate contact with the face of the perforated metal film which bears the smaller diameter ends of said perforations to prevent the first and second layers from separating from each other.
Claim 3
Dependent Claim
22 words
A transcutaneous probe according to claim 1 wherein portions of said plastics film extend into the perforations in the said metal film.