BASIC PRINCIPLES OF DIALYSIS.pptx

principles of hd

1. BASIC PRINCIPLES OF DIALYSIS

2. 1) DIFFUSION Movement of molecules from a region of higher concentration to a region of lower concentration until the equilibrium is reached.

3. Types of Diffusion Simple Diffusion : Substance moves through a semi permeable membrane or In a solution without the help of transport proteins Facilitate Diffusion : Substance move through a semi permeable membrane or in a solution with the help of transport proteins

4. In Dialysis, Diffusion can be defined as transport of solute across the semipermeable membrane through a concentration gradient. Solutes ex: Na+, K+, Ca+, Urea, Glucose, Cl-

5. Diffusion is bi directional From Blood to Dialysate => Diffusion From Dialysate to Blood => Back Diffusion

6. Factors affecting rate of diffusion Temperature: Higher the temperature faster the diffusion (Reason; higher the temperature the particles will be having more kinetic energy.) Surface area: larger surface area of membrane = faster diffusion Concentration: if concentration gradient is higher diffusion will be faster

7. Counter current mechanism will help for faster diffusion

8. 2) Osmosis During osmosis, fluid moves from areas of high water concentration to lower water concentration across a semi-permeable membrane until equilibrium is reached. In dialysis, excess fluid moves from blood to the dialysate through a membrane until the fluid level is same between blood and dialysate.

9. 3) Transmembrane pressure(TMP) Difference in hydrostatic pressure between the Blood compartment and the Dialysate compartment across the dialysis membrane this is called the Transmembrane pressure (TMP).

10. TMP alarm in Dialysis machine Causes: 1. Clamped line 2. Clotted Dialyzer 3. Kink Dialysate line 4. Poor vascular access 5. High UFR 6. Measurement error 7. Ruptured membrane 8. Protein deposit in membrane

11. Management Check the line for kink Check the shunt connection with dialyzer Flush the dialyser to check clot in dialyzer Check Transducer protector(TP) whether it is dry or wet If TMP is lower increase UF or Increase blood flow

12. 4) Venous Pressure Normal range of venous pressure is 100-200mmHg. Maximum pressure is 300mmHg.

13. High Venous pressure

14. Low Venous Pressure

15. 5) Ultrafiltration Ultrafiltration is the removal of fluid from a patient. Ultrafiltration occurs when fluid passes across a semipermeable membrane (a membrane that allows some substances to pass through but not others) due to a driving pressure.

16. Ultrafiltration removes excess plasma volume without causing a significant change in electrolytes In majority of patients we do need ultrafiltration needs. Some units mention a minimum UF rate, such as of 10ml/hr or 500 ml (200 ml for a drink + 300 ml for restitution of the blood at end of a session). The limit of ultrafiltration rate (UFR) monitored by the Centers for Medicare or Hospitals is 13 ml/kg per hour.

17. THANK YOU