Apparatus and method for continuous monitoring of tissue gas composition and pH using recirculating gas tonometry
First Claim
1. A tonometry catheter apparatus comprising:
- an elongate flexible tube having a proximal extracorporeal end and a distal intracorporeal end;
the distal end of the tube havinga distensible, inflatable, gas-permeable tonometry vessel, the vessel and the distal end defining therebetween a space which is filled with a gas,an egress orifice in communication with the space, through which gas may enter the vessel,an egress lumen with a distal end and a proximal end, the distal end being in communication with the egress orifice,an ingress orifice in communication with the space, through which the gas may exit the vessel, andan ingress lumen with a distal end and a proximal end, the distal end being in communication with the ingress orifice,wherein the diameter of the ingress orifice is larger than the diameter of the egress orifice so as to prevent overdistention of the vessel;
the proximal end of the tube havinga propeller for propelling gas into the vessel, the propeller being selected from a group consisting of a peristaltic pump, a roller pump, an impeller pump, a blower, a fan, a circulator, and their equivalents,a quantifier for continuously quantifying the level of gas exiting the vessel, anda hollow connecting member linking the propeller and the quantifier to define with the vessel, the ingress lumen, and the egress lumen a closed circuit through which the gas may continuously recirculate, thereby resulting in a substantially error-free, stable reading of gas composition within the circuit.
1 Assignment
0 Petitions
Accused Products
Abstract
A tonometry catheter apparatus comprises an elongate, flexible, multilumen tube having a proximal end to be positioned outside the human body and a distal end to be positioned within a portion of the human body. Provided at the distal end are an ingress lumen through which gas may enter the tube, and an egress lumen through which gas may exit the tube. A hollow connecting member links the ingress lumen and the egress lumen to define a sampling circuit through which the gas may continuously recirculate. In one embodiment, the distal end of the tube is provided with a distensible, gas-permeable vessel in communication with the ingress and egress lumens. In an alternative embodiment, an extracorporeal gas-permeable membrane links the sampling circuit to a separate, gas-containing analyzing circuit. In each embodiment, a pump is provided for propelling gas through the circuits, and a sensor continuously quantifies the level of gas within the circuits.
-
Citations
41 Claims
-
1. A tonometry catheter apparatus comprising:
-
an elongate flexible tube having a proximal extracorporeal end and a distal intracorporeal end; the distal end of the tube having a distensible, inflatable, gas-permeable tonometry vessel, the vessel and the distal end defining therebetween a space which is filled with a gas, an egress orifice in communication with the space, through which gas may enter the vessel, an egress lumen with a distal end and a proximal end, the distal end being in communication with the egress orifice, an ingress orifice in communication with the space, through which the gas may exit the vessel, and an ingress lumen with a distal end and a proximal end, the distal end being in communication with the ingress orifice, wherein the diameter of the ingress orifice is larger than the diameter of the egress orifice so as to prevent overdistention of the vessel; the proximal end of the tube having a propeller for propelling gas into the vessel, the propeller being selected from a group consisting of a peristaltic pump, a roller pump, an impeller pump, a blower, a fan, a circulator, and their equivalents, a quantifier for continuously quantifying the level of gas exiting the vessel, and a hollow connecting member linking the propeller and the quantifier to define with the vessel, the ingress lumen, and the egress lumen a closed circuit through which the gas may continuously recirculate, thereby resulting in a substantially error-free, stable reading of gas composition within the circuit. - View Dependent Claims (2, 3, 4)
-
-
5. A tonometry catheter apparatus comprising:
-
an elongate flexible tube having a proximal extracorporeal end and a distal intracorporeal end; the distal end of the tube having a distensible, inflatable, gas-permeable tonometry vessel, the vessel and the distal end defining therebetween a space which is filled with a gas, an egress orifice in communication with the space, through which gas may enter the vessel, an egress lumen with a distal end and a proximal end, the distal end being in communication with the egress orifice, an ingress orifice in communication with the space, through which the gas may exit the vessel, and an ingress lumen with a distal end and a proximal end, the distal end being in communication with the ingress orifice, the proximal end of the tube having a propeller for propelling gas into the vessel, the propeller being selected from a group consisting of a peristaltic pump, a roller pump, an impeller pump, a blower, a fan, a circulator, and their equivalents, a quantifier for continuously quantifying the level of CO2 gas exiting the vessel, and a hollow connecting member linking the propeller and quantifier to define with the vessel, the ingress lumen, and the egress lumen a closed circuit through which the gas may continuously recirculate, thereby resulting in a substantially error-free, stable reading of gas composition within the circuit; wherein the gas contained within the circuit comprises a mixture of a nontoxic gas and a physiologic concentration of CO2 gas prior to placement of the vessel within the body of a patient so as to facilitate equilibration with the gas concentration adjacent the vessel. - View Dependent Claims (6, 7, 8)
-
-
9. A tonometry catheter apparatus comprising:
-
a sampling circuit and an analyzing circuit through which fluid may continuously recirculate; the sampling circuit having a proximal end and a distal end, the distal end of the sampling circuit in communication with a space which is filled with a fluid to be sampled, an ingress lumen in communication with the space, through which fluid may exit the space and enter the sampling circuit, and an egress lumen in communication with the space, through which the fluid may exit the sampling circuit and enter the space; the analyzing circuit having a sensor for quantifying the level of fluid within the space; wherein a segment of the sampling circuit and a segment of the analyzing circuit share a common interface which permits gaseous diffusion between the sampling circuit and the analyzing circuit. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
-
-
34. A method for indirect monitoring of organ or tissue gas composition comprising:
-
providing a catheter having an elongate flexible tube, the tube having a distal end and a proximal end; introducing the catheter into an organ of interest so that the tube distal end is disposed at a desired sampling site; positioning the tube distal end at the sampling site for a length of time sufficient to allow fluid at the sampling site to enter an ingress orifice provided within the tube; circulating the fluid within a sampling circuit defined by the ingress orifice, an egress orifice, and a first hollow member connecting the ingress and egress orifices; allowing gas to diffuse out the sampling circuit into a second hollow member which is filled with a gas and defines a closed analyzing circuit via a common, gas-permeable interface disposed therebetween; and analyzing gas within the analyzing circuit to determine the gas composition of the organ into which the catheter was placed. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41)
-
Specification