SYSTEM FOR CONTINUOUS
WITHDRAWAL AND ANALYSIS OF BLOOD
 Inventor: Allen A. Kowarski, Baltimore, Md.
 Assignee: The Johns Hopkins University, Baltimore, Md.
 Filed: Mar. 5, 1976
 Appl. No.: 664,178
Related U.S. Application Data
 Continuation-in-part of Ser. No. 587,724, June 17, 1975, which is a division of Ser. No. 323,985, Jan. 15, 1973, Pat. No. 3,908,657.
 U.S. CI 128/214 R; 128/278;
128/214.4; 128/218 A; 128/2 F; 128/214 B
 Int. CI.2 A61B 5/00; A61M 1/00
 Field of Search 128/214 R, 214 B, 278,
128/334 R, 2 F, 348
 References Cited
UNITED STATES PATENTS
2,183,318 12/1939 Burton 128/214 R
3,425,418 2/1969 Chvapil et al 128/334 R
3,496,878 2/1970 Hargest et al 128/214 R
3,579,441 5/1971 Brown 210/23
3,582,234 6/1971 Isreeli 417/53
3,688,317 9/1972 Kurtz 3/1
3,701,350 7/1970 Guenther 128/214 B
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 disposal 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 The subject may then move about for a selected period when blood is being slowly withdrawn at a prescribed rate and collected in a container within a housing supporting the device.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 glucose, growth hormone or other material in blood. In addition, a portable microdiffusion chamber is incorporated between the indwelling catheter and the extra corporal tubing and is electrically connected through a sensor probe to an associated sensory responsive device. This permits continuous analysis of the withdrawn blood to determine the in vivo concentration of circulating concentrations of materials in the blood.
14 Claims, 8 Drawing Figures