Question

1. Explain the pathophysiological conditions which necessitate the use of dialysis machine.
2. Explain the mechanism underlying dialysis using a typical dialysis machine.
3. Explain the challenges involved in the use of the dialysis machine

Answer 1

1)When a person’s kidney fails to function properly, this leads to fluid and waste build up in the body and may need dialysis. The kidneys play an important role in the filtering of blood, metabolism, excretion of endogenous and exogenous compounds and endocrine system. The kidney failure is mainly caused by other health problems that may harm the kidney over time. This is chronic type failure and failure may be acute when the kidney stops functioning suddenly. Most common causes found for the kidney failure is diabetes and high blood pressure. Other problems that may cause kidney failure are genetic diseases like polycystic kidney disease, autoimmune diseases, nephrotic syndrome etc. And acute failure may be a result of heart attack, drug abuse, infections etc. The main symptoms include nausea, vomiting, swelling in feet, too much or not enough urine etc. Any of these causes may interfere with kidneys ability to maintain the fluid balance and electrolyte balance. The concentration and dilution of urine is not effective and excretion of potassium, phosphate, acid is ineffective. The water intake and urinary volume is not regulated properly. This affects the homeostasis mechanism of the body that results in increase in waste build up in blood. The glomerular filtration rate (GFR) reduces to less than 15 mL/min/1.73 m2 . Concentration of creatinine and urea begins to rise as GFR rate is reduced. Calcium, phosphate and parathyroid hormone, vitamin D metabolism etc. is affected. When this happens Dialysis or kidney transplant is the treatment options available.

2) During hemodialysis the blood is filtered using a dialyzer. Two needles are placed in the arm with catheters attached to it. The dialyzer starts by blood entering through the tube to the filter and is forced to thin hollow fibers. A solution called dialysate which is a mix of electrolyte and dextrose flows in the opposite direction. Blood and the solution is separated by a thin membrane that only waste products like urea, creatinine, potassium, extra fluids only can pass. Waste products remain in the dialysate and the filtered blood enters back to the body through other tube.

Peritoneal dialysis is a dialysis that uses a tube called peritoneum permanently fixed in the peritoneal cavity of abdomen of the person with kidney failure. This has a membrane that helps filter excess fluids and waste from the body. During the dialysis the dialysate is passé through this tube to filter the blood.

3) The technological advancements improved the equipment for dialysis, but there are still challenges involved in dialysis machine. They are

-patients characteristics like obesity, malnutrition, prior abdominal surgeries etc. may make it hard to choose a dialysis modality.

- The dialysate solution’s temperature, concentration of electrolyte and dextrose, osmotic pressure, conductivity etc. may affect the dialysis.

-The dialysis machine hardware failure includes water treatment systems replacement or service, reverse osmosis and carbon tanks service has to be ensured in case of a mechanical failure. Power failure may also need a backup.

-Any malfunctioning or mistake in the needle or catheter placement or disconnection of the catheter is a challenge. So the person handling this should be a specialized and trained person. This can minimize any such errors.

-dialyzer rupture is also a failure that is associated with dialysis machine. Troubleshooting and backup plans should be needed to bridge these difficult situations.

-The person operating the machine may cause programming of automated cycler error.

-Any leak of blood through tube or ruptured dialyzer is a challenge.