Hemodialysis Hemodialysis MachineMachine

Kidney Function

Calcium Balance

Vitamin DActivation

Recovery of Bicarbonate

Sodium Removal

Bone Structure Metabolic End

Products

Cardiac Activity

Regulation of Blood PH

Blood Pressure

Blood Formation

Removal of Urea ,Creatinine etc .

Potassium Balance

Water Balance

Erythropoietin Synthesis

Need Dialysis is a treatment for people in the later stage of

kidney failure (chronic renal insufficiency). This treatment cleans the blood and removes wastes

and excess fluid from the body, which are normally removed by healthy kidneys.

Sometimes dialysis is a temporary treatment (acute). However, when the loss of kidney function is permanent, as in end-stage kidney failure, dialysis is required on a regular basis (chronic).

The only other treatment for kidney failure is a kidney transplant. 

Types

There are two types of dialysis: hemodialysis and peritoneal dialysis. In hemodialysis, blood is passed through an artificial kidney (hemodialyzer) to clean it. Peritoneal dialysis uses a filtering process similar to hemodialysis, but the blood is cleaned inside the body rather than in a machine. 

The process of diffusion

1.

                                              

2.

                                              

 Blood cells are too big to pass through the dialysis membrane,  but body wastes begin to diffuse (pass) into the dialysis solution.

3.

                                              

 Diffusion is complete. Body wastes have diffused through the membrane,  and now there are equal amounts of waste in both the blood and the  dialysis solution.

The process of ultrafiltration in PD 11.

                                               

22.

                                               

 Blood cells are too big to pass through the semi-permeable membrane,  but water in the blood is drawn into the dialysis fluid by the glucose.

3.

                                               

 Ultrafiltration is complete. Water has been drawn through the peritoneum by the glucose in the dialysis fluid  by the glucose in the dialysis fluid. There is now extra water in the dialysis  fluid which need to be changed.

Diffusion Diffusion / dialysis– the movement of solutes

from a compartment in which they are in high concentration to one in which they are in lower concentration – along an electrochemical gradient.

An electrolyte solution runs countercurrent to blood flowing on the other side of a semipermeable (small pore) filter.

Small molecules such as urea move along the concentration gradient into the dialysate fluid.

Larger molecules are poorly removed by this process. Solute removal is directly proportional to the dialysate flow rate.

Difusion

By controlling the chemicals in the dialysate, the dialysis machine controls this transfer of solutes according to the doctor's prescription.

Dialysis machines control the chemicals in the dialysate by mixing dialysis fluid concentrates, which are strong versions of the chemicals, (acetate or sodium bicarbonate plus acetic acid based solutions) with purified water

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• Small molecules (less than 68 000 molecular weight) are removed from the blood by using the high blood pressure to squeeze the molecules from the glomerulus to the Bowman’s capsule.

• The small molecules include:– Water– Glucose– Urea– Sodium Chloride– Amino acids and small proteins

Ultrafiltration

Ultrafiltration

Ultrafiltration, also referred to as convection, is fluid flow through the membrane, forced by a difference in pressure on the two sides of the dialyzer (pressure gradient).

This controls the patient's weight loss over the course of the treatment.

This is very effective in removal of fluid and middle-sized molecules, which are thought to cause uremia

Ultrafiltration

While earlier dialysis machines either controlled dialysate pressure or the pressure difference across the membrane in order to achieve ultrafiltration.

Modern dialysis machines are generally volumetric, meaning they control the volume of fluid removed from the patient directly and allowing dialysate pressure to change as it will in order to achieve the prescribed weight loss.

Osmosis Osmosis is the net movement of water

across a selectively permeable membrane driven by a difference in the amounts of solute on the two sides of the membrane.

In dialysis, this refers not to water movement across the hemodialyzer membrane, but across cell membranes within the body-either from within the red cells to the blood plasma, or from within cells of the various tissues in the body (like muscles) to interstitial fluid (the fluid in between cells)

Artificial Kidney / Dializer

Thin material separates the compartments

Blood and dialysate flow in opposite directions

Dialysate drains the wastes out of the blood

Clean blood is returned to the body

Artificial Kidney / Dializer

Dialyzer Characteristics

1- Biocompatibility( how much a membrane is compatible with human body )

2- Membrane Surface Area

3- Molecular Weight ( the solute size that can pass through the membrane ).

4- Ultrafiltration Coefficient

5- Clearance ( the rate of solute removal )

Dialysis Solution

Dialysis solution, also known as dialysate, is the fluid in the dialyzer that helps remove wastes and extra fluid from the blood, as well as regulate blood pH and proper level of the ion concentrations. It contains chemicals in low concentrations.

Blood is pumped with the peristaltic pump through the capillaries, the dialyzing solution is flowing around the capillaries in opposite direction.

Dialysis Solution (Dialysate) Function

Fluid in the dialyzer that contains chemicals in low concentrations .

This solution are : Bicarbonate and Acetate .

Functions :- 1-Remove the wastes and

extra fluid from the blood 2-Regulate blood PH and

proper level of the ion concentration .

Components for Hemodialysis machine

♦-Single patient hemodialysis systems can be divided into three major components :-

1- dialysate delivery system.

2- The extracorporeal blood-delivery circuit .

3- The dialyzer .

Components for Hemodialysis machine

How Dialysis Work

Hemodialysis Machine Parts

Parameters monitoring in Hemodialysis Machine

1- Blood Flow .2-Dialysate Flow.3- Dialysate Temperature.4- Conductivity .5- Venous and Arterial pressure.6-Blood in dialysate leaks.7- Patient blood pressure.

When the air detector senses air it will trigger audible and visual alarms, stop the blood pump and clamp the venous blood tubing to keep air from getting into the patients bloodstream.

Air Detectors

Ultrafiltration Dialysis machine causes hydraulic pressure There is higher pressure in blood

compartment than in the dialysate compartment

This forces water and any other molecules small enough to pass through the membrane to evacuate the blood.

Single Patient Dialysate Delivary System

Volumetric UF Control System

The extracorporeal blood-delivery circuit