Capillary filtration and collection device for long-term monitoring of blood constituents

A capillary filtration and collection system, comprising:

• a filter including at least one hollow fiber compatible for long-term patency within an interstitial space of a body in fluid communication with blood capillaries and having a porous outer surface having pore sizes less than approximately 300,000 daltons;
• an ultrafiltrate collector including a tube connected to said filter in fluid communication therewith and adapted to extend externally of the body with said filter implanted within an interstitial body space;
• and
• a negative pressure generating means for generating a negative pressure for withdrawing an ultrafiltrate of blood through said filter and into said ultrafiltrate collector at a desired flow rate in a range from about 20 to 500 microliters per hour.

A capillary filtration and collection system for monitoring a physiological constituent of blood, comprising:

• a filtration means for filtering a plasma ultrafiltrate from blood capillaries in an interstitial space inside a body, said filtration means including an unsupported porous filter made of a material compatible for long-term patency inside the body, said filter adapted to be implanted inside the body in fluid communication with blood capillaries in the interstitial space and having pores sized not greater than approximately 300,000 daltons;
• an ultrafiltrate collector including an elongate tube connected to said filter in fluid communication therewith and adapted to extend externally of the body with said filter implanted inside the body;
• and
• a negative pressure generating means for generating a negative pressure relative to atmospheric for withdrawing the plasma ultrafiltrate through said filter and into said ultrafiltrate collector.