DIALYSIS CONSUMABLES - TECHNICAL EXPLANATIONS

      Dialysis Consumables

      Technical Specifications

        1) Hollow fiber dialyzer

             

The dialyzer is also called an Artificial Kidney comprised of 2 compartments namely a Blood compartment & dialysate compartment.  The blood compartment has tiny hollow fiber membranes open from both ends meant to carry blood from one end to the other enabling toxic waste & fluid from the blood to get pumped out into the dialysate compartment.  The gap between these open ends of hollow fiber membranes are fused by using potting material Polyurethane so that blood will just enter hollow fiber membrane and not in between the spaces causing blood leak into the dialysate compartment.

Dialysate compartment OR filtrate compartment, as shown in the image, is the empty space surrounding these hollow fiber membranes placed in a cylindrical body made up of polycarbonate.  Dialysate compartment has 2 openings one for dialysate to enter and the other one for dialysate to leave the compartment along with metabolic waste and fluid moving towards the drain.

The direction of blood and dialysate is recommended to be kept in the opposite direction from each other to enable the maximum utilization of the available surface area enhancing the efficiency of dialysis.  It is called a counter-current mechanism.

The dialyzer membrane will be porous enough to let metabolic waste & electrolytes along with water pass through.  This helps in the diffusion of metabolic waste from blood to the dialysate compartment.  Depending upon the pore size of the membrane it is categorized into low flux & High flux dialyzers.  Also, one of the criteria is whether it removes small, middle & large molecules (solute permeability).  The capacity of the membrane to remove fluid is another criterion that determines whether it is a low flux or High flux dialyzer (Ultrafiltration coefficient)

          2) Blood lines:

       

The bloodline used for hemodialysis has two segments namely an Arterial segment and the venous segment.  The arterial segment will have different sizes of clamps & caps color-coded with a red and venous segment with blue color so as to differentiate between arterial and venous segments easily.  The arterial segment starts with a narrow opening (53) on one side that helps in sucking blood with pressure.  Followed by the opening there will be a plastic red color clamp (74) that enables stop & start of the flow while connecting/disconnecting the process.  After the arterial clamp, there will be an injection port (50), the same port is seen in the venous segment (72) for any injection to be administered pre or post dialyzer during dialysis.  A line no (44) in the arterial segment and line no. (62) in the venous segment can also be used for the administration of I.V. injections in large amounts if at all to be administered slowly.  

After the injection port, there will be an Arterial chamber (40) with 1 or 2 lines (42), one for the monitoring of the arterial pressure and the other one, an extra line for administration of injections and maintaining the blood levels inside the chamber with the help of a syringe.  From the arterial chamber, blood enters the blood pump segment (32).  This segment will be slightly large in diameter as compared to the rest of the bloodline.  The length & the diameter of the blood segment will be printed on the brochure & the bloodline plastic cover.  The machine has to be calibrated according to the segment diameter recommended by the manufacturers.  This blood pump segment will have cuffs on both ends to avoid the accidental slip of the blood segment from the blood pump (33).  From the blood pump segment now the blood will be carried to the dialyzer (10) for the actual purification process.  The purified blood then gets into the venous chamber (64).  The venous chamber will have 2 lines emerging out for the purpose of monitoring the venous pressure and one for either injecting injections or leveling of the blood in the venous chamber.  From the venous chamber, blood enters the patient body through the venous end of the bloodline (76).

3) Acid concentrate & Bicarbonate solution:

Mainly we need 2 solutions for the dialysis process.  One is called the Acid concentrate and the other one Bicarbonate.   We also call them A & B parts or concentrates.   Acid & bicarbonate together with water form dialysate which has electrolytes such as sodium, potassium, calcium, chloride, acetic acid & bicarbonate.  The proportion of these electrolytes in the dialysate is adjusted in such a way that it matches their normal physiological levels in the blood so that patients can remain stable without losing any electrolytes through a process of diffusion.  

Bicarbonate is a buffer solution that corrects patients’ blood acidosis (PH).  Following is the list of the various electrolytes in the dialysate and their proportion. 

Sometimes Acid concentrate proportion is altered for some electrolytes like potassium & calcium for the special cases with hyperkalemia & hypercalcemia.  That means these electrolytes will not be present in the dialysate solution or they will be in minimal quantity so that higher concentration of these electrolytes from the blood can be reduced with the help of the diffusion process. 

      4) A.V.Fistula Needles:

     A.V. Fistula needle is a part of the dialysis equipment.  It is used to cannulate patient fistula to access blood.  Fistula needles are available in different sizes such as 15G, 16G, 17G, etc.  The choice of needle size depends upon the development of the A.V, Fistula connected vein & its prominence.     

     

     General Specification

• Sterilized by Ethylene Oxide.
• For single use only.
• Non-pyrogenic
• Colour coded wings for size recognition.
• wings are designed for perfect gripping during insertion effortless fixation.
• Available with Red, Blue or White clamps.
• Available in 15G, 16G, 17G sizes.