Apparatus for the exchange of cerebrospinal fluid and a method of treating brain and spinal cord injuries

An apparatus for the exchange of cerebrospinal fluid comprising:

• an extra-thin walled stainless steel cannula for puncturing a spinal canal, a said cannula having an outside diameter of about 1.47 mm and an internal diameter of about 1.25 mm;
• a silicone elastomer catheter for inserting into said cannula and for indwelling in the subarachnoid compartment of said spinal canal, said catheter having an outside diameter of about 1.22 mm and an inside diameter of about 0.97 mm;
• a flange for retarding leakage of said cerebrospinal fluid from said spinal canal by engaging said spinal canal at the puncture site, said flange being attached to the external surface of said catheter;
• a first container for holding cerebrospinal fluid;
• a fiber cartridge for micro-filtration of cerebrospinal fluid by tangential flow filtration, said fiber cartridge having a pore size of about 0.2 m.mu. and a membrane surface area of at least about 450 cm.sup.2 ;
• a second container for storing filtered cerebrospinal fluid;
• a means for moving said cerebrospinal fluid, including, a reversible peristaltic pump with a volume range of about 0.07 to 25 liters per hour and an operating pressure of less than about 30 PSI, a three port valve means for regulating the direction of flow of said cerebrospinal fluid, and a fluid loop for carrying said cerebrospinal fluid,
• wherein said fluid loop connects said catheter to said three port valve means;
• said three port valve means to said first container and said second container;
• and said filtration device to said first container and said second container;
• and
• a temperature probe for measuring the temperature of said cerebrospinal fluid;
• a temperature regulating means connect to said temperature probe for controlling the temperature of said cerebrospinal fluid;
• a flow meter for measuring the volume of cerebrospinal fluid;
• bi-directional pressure transducers for monitoring cerebrospinal fluid pressure;
• a spectrophotometer for monitoring transmittance of the cerebrospinal fluid;
• a computer for regulating the exchange of said cerebrospinal fluid and for controlling the treatment and flow of said cerebrospinal fluid;
• a computer station connected to said computer for displaying results, said computer station includes a monitor, a printer and a warning means;
• and
• an interface for connecting said computer to said peristaltic pump, said three port valve means, said pH electrode, said temperature probe, said flow meter, said pressure transducers, said spectrophometer and said temperature regulating means.

The method of exchanging cerebrospinal fluid in a vertebrate comprising the steps of:

• collecting cerebrospinal fluid from said vertebrate;
• treating the collected cerebrospinal fluid;
• monitoring the physical and chemical parameters of the cerebrospinal fluid;
• returning the treated cerebrospinal fluid to said vertebrate;
• and
• regulating the collecting, treating, monitoring and returning of said cerebrospinal fluid.

A method for continuously removing blood, blood byproducts and other impurities from cerebrospinal fluid comprising the steps of:

• collecting said cerebrospinal fluid with a catheter inserted into the subarachnoid compartment, said catheter having an outside diameter of about 1.22 mm and an internal diameter of about 0.97 mm;
• micro-filtering said cerebrospinal fluid with a hollow fiber cartridge and tangential flow filtration;
• monitoring physical and chemical parameters of said cerebrospinal fluid with a monitoring means including means for measuring pH, pressure, temperature, volume and percent transmission;
• returning said filtered cerebrospinal fluid to said vertebrate;
• and
• regulating the collecting, filtering, monitoring and returning of the cerebrospinal fluid with a computer interfaced to said collecting, filtering and monitoring means, wherein said computer receives signals from the monitoring means and sends signals to the collecting filtering and returning means.

The method of treating brain and spinal cord injury including the steps of:

• continuously collecting cerebrospinal fluid from an injured vertebrate;
• cooling said cerebrospinal fluid;
• filtering said cerebrospinal fluid;
• monitoring physical and chemical parameters of said cerebrospinal fluid;
• and
• returning treated or artificial cerebrospinal fluid to said vertebrate.