Abstract A small, portable, constant withdrawal device is connected to tubing, including a catheter, whose internal walls are coated with heparin. The catheter is inserted intravenously through a disposable needle into a subject such as a human being. The subject may then move about for a selected period when blood is being slowly withdrawn at a prescribed rate and collected in a container within a housing supporting the device. The collected blood may then be analyzed to permit the measurement of the integrated concentration of growth hormone or any substance whose concentration in blood fluctuates widely. In addition, a portable microdiffusion chamber is incorporated between the indwelling catheter and the extra corporal tubing and is electrically connected through a sensing probe to an associated portable sensory responsive device. This permits analyzation of the extracted blood to determine the in vivo concentration of circulating concentrations of the diffusable fraction of biological materials in the blood.
A method for continuously withdrawing blood from a subject, comprising the steps of: inserting a catheter having a nonthrohmbogenic passageway therethrough into a vein of a subject; causing blood to move continuously from the vein into and through the passageway; continuously collecting said blood withdrawn through the catheter; and controlling the continuous withdrawal of said blood slowly from said vein at a pre-determined constant rate and for a pre-determined extended time during which the catheter is in the vein of the subject.
Claim 2
Independent Claim
82 words
A method for continuously withdrawing blood from a subject, comprising the steps of: inserting a catheter having a nonthrohmbogenic passageway therethrough into a vein of a subject; causing blood to move continuously from the vein into and through the passageway; continuously collecting said blood withdrawn through the catheter; and controlling the continuous withdrawal of said blood slowly from said vein at a pre-determined constant rate and for a pre-determined extended time during which the catheter is in the vein of the subject.
Claim 3
Dependent Claim
58 words
The method of claim 1 wherein the step of causing blood to move continuously from the vein into and through the passageway includes the step of continually biasing inwardly at least a portion of that portion of the catheter which is disposed externally of the subject to continuously control the rate of passage of blood through the catheter.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein the continuous withdrawal of blood through the catheter is controlled for a pre-determined extended time up to at least 24 hours.
Claim 5
Dependent Claim
10 words
The method of claim 5 wherein the anti-coagulant is heparin.
Claim 6
Dependent Claim
30 words
The method of claim 1 wherein said nonthrombogenic passageway of said catheter is so rendered by treatment thereof with an anticoagulant prior to insertion of said catheter into said vein.