DIALYSIS.

Syeda Yousra

It is performed when a person experiences 95% kidney failure.

Like healthy kidneys, dialysis keeps the body in balance by removing waste products including salt and excess fluids and controlling blood pressure

Why is it necessary????

When there is kidney damage or kidney disease, and the kidneys are not able to filter waste efficiently, there will likely be a rise in creatinine levels in the blood. For adults with kidney disease, dialysis is recommended when creatinine levels reach 10.0 mg/dL. For babies with kidney disease, dialysis is recommended when their creatinine level is 2.0 mg/dL.

Principle • Principle of dialysis - Diffusion of solutes

and ultrafiltration of fluid across a semi-permeable membrane. – Diffusion is a property of substances in water; substances in

water tend to move from an area of high concentration to an area of low concentration.Blood flows by one side of a semi-permeable membrane, and a dialysate, or special dialysis fluid, flows by the opposite side.

– Smaller solutes and fluid pass through the membrane, but the membrane blocks the passage of larger substances (for example, red blood cells, large proteins). This replicates the filtering process that takes place in the kidneys, when the blood enters the kidneys and the larger substances are separated from the smaller ones in the glomerulus.

TYPES

• Haemodialysis.• Peritoneal Dialysis.

Haemodialysis

• Here an artificial kidney, haemodialyser is used to remove the waste products from the blood and restore the body’s chemical balance.

How is it done?

• A blood vessel with a rapid flow of blood that is also close to the skin is needed.

• It does not exist naturally, an access has to be made during a short surgery.

Fistula and Graft.

• A Fistula is made by connecting a vein to a nearby artery.– Blood flows rapidly into the vein making it larger. It

takes weeks/months before a fistula is ready for use.

• A Graft is sewn between the artery and vein. – Blood flows rapidly into through the graft from the

artery to the vein. This is usually ready for use within a week or two.

Working of haemodialysis.

• Plastic tubing attached to the needles connects the patient to the artificial kidney.

• This contains two compartments, one for the patient’s blood and one for a cleaning solution called dialysate.

• A thin porous membrane seperates these compartments.

• Blood cells, protein and other important substances in the blood remain in their compartments as they are larger.

• The smaller waste products like urea and creatinine in the blood and excess water pass through the holes of the membranes and are washed away.

• The clean blood now enters the patients body.• Haemodialysis is done approximately for 3-4

hours and is usually three times a week.

Characteristics of haemodialysis

• Takes only 3-5 hours per treatment.• Requires only 3 treatments weekly.• Requires surgical creation of vascular access

between circulation and dialysis machine.• Requires complex water treatment, expensive

dialysis equipment and highly trained personnel.• Requires large dose of heparin.• Confines patient to special treatment unit.• Risk of complication.

Peritoneal dialysis.

• Here the patients blood is cleaned continously within the body, the blood stays in the blood vessels which line the patients andominal(peritoneal) space. The lining of the space acts like a membrane in the artificial kidney.

Working of peritoneal dialysis.• A catheter is surgically placed to create an

access.• The dialysate is slowly filled through the

catheter.• The exchange of waste products and chemical

balancing take place. • Once the exchange is completed, the used

dialysate is drained from the peretonial cavity.

• This type of dialysis is mostly performed by the patients themselves.

• There are 3 types– CAPD –Continuous Ambulatory Peretonial Dialysis is

done for 4-5 hours and is usually 4-5 times a day– CCPD- Continuous Cycling Peretonial Dialysis lasts

about 1hour 30 minutes and is done several times a night

– IPD- Intermittent peritoneal dialysis is the oldest form and lasts about 10-12 hours, 3 times a week.

Characteristics • Can be performed immediately.• Requires less complex equipment and less specialised

personnel.• Requires small amount of heparin or none at all.• Can be performed by patient anywhere without

assistance.• Allows patient independence without long interruption

in daily activities.• Allows for more liberal diet.• Costs less.

Dietary management.

• Requirement for haemodialysis– Energy – 35 kcal/kg body weight– Protein – 1.1g/kg

• For CAPD/CCPD– Protein 1.3g/kg

• Dietary salt, potassium, phosphorus and water intake should be restricted to– Salt 3-4g, k+ 50-70mEq/day, phosphorus 1g/day and

water according to the urine output of the patient.

Drawbacks.• Dialysis can only control the kidney failure and does not

cure the diseased kidneys.• Patients with chronic kidney failure need to continue

dialysis throughout their lives or until they receive kidney transplant.

• Discomfort is seen when needles are inserted for haemodialysis.

• Patients may also experience a drop in blood pressure accompanied by nausea, vomitting, headaches and cramps.

• Dialysis is very expensive.

Prevention

• Treating diabetes mellitus and hypertension with lifestyle modification is essential to prevent kidney damage.

Urolithiasis or Urinary Calculi

• These are found, lodged in the urinary tract namely, kidney, ureters, bladder or urethra.

• Sometimes there is blood in the urine and the stones can cause intense pain.

• Renal stones are prevalent between 30-45 years of age. Relapse is common.

Causes

• May be due to nutritional status, dietary habits and environmental factors like temperature and humidity.– Climate : In warm climates, the urine volume is

low and concentrated with urates, oxalates and calcium salts. In India this is found in Rajasthan, Saurashtra and Punjab may be due to excessive heat or water scarcity.

– Occupation : people who work directly under the sun and perspire a lot ,pass concentrated urine.

– Infection of urinary tract : frequent infection of the urinary tract which causes puss cells formation and epithelial cells may form a focus around which the stone may be formed.

– Dietary habits : intake of foods rich in oxalates, calcium, purines and phosphates may predispose to form calculi. Diets rich in sodium, fats ,meat and sugar and low in fibre, vegetable protein and unrefined carbohydrate increase the risk.

– Heridity.– Vitamin A and B complex deficiency.– hyperthyroidism

Types

• Calcium phosphate• Calcium oxalate• Uric acid or magnesium ammonium

phosphate.

Calcium oxalate calculi

• Formation of calculi depends upon the balance between the concentration of precipitating substances like calcium phosphate, oxalic acid, uric acid, Mg and crystal inhibitors in urine.

• Volume and pH of urine • High intake of animal protein like meat, fish

and poultry.

• Pyridoxine deficiency increases the production of oxalic acid in the body and its excreation in the urine.

• Excess intake of vitamin C• Foods rich in oxalates like spinach, cabbage and

tomatoes• People residing in rocky areas are more prone

because the drinking water may be hard or may contain some elements.

Studies conducted.

• Studies conducted at NIN, Hyderabad (1982) reported that in Punjab the incidence of Urolithiasis is higher where fluoride content of drinking water is high and this helps in the growth of urinary calculi.

Diet for the prevention of renal calculi

• Low oxalic acid and purine content• Calcium and phosphates should be reduced to

moderation• Large amount of fluids to increase urine

output to 2-2.5 litres per day.• High ratio of Mg to Ca foods such as brown

rice, bananas and oats to be given

• Mg supplementation may decrease the size of and existing stone and prevent further formations.

• Foods to avoid– Alcohol , antacids, excessive protein, dairy, salt,

carbonated beverages, caffeine and refined white flour, coffee, iced tea,cola etc

Treatment.• Acid or alkaline ash diet is not very effective in

bringing about solution of stones formed but may prevent the recurrence of stones.

• Planning Acid ash diet– Liberal fluid intake– Salt in moderation– The fruits and vegetables should not contribute

more than 25ml of base daily.

• Planning Alkaline-ash diet.– For uric acid stones- alkaline producing foods like -

fruits, vegetables and milk. Acid producing foods like meat, eggs and cereals to be restricted.

• Planning low oxalate diets– Food sources of oxalates to be omitted like beans,

beet greens, chocolate, cocoa, dried figs,plums, potatoes, spinach, tea and tomatoes.

Dietary management

• Fluids – supply adequate fluids like water coconut water and barley water fruit juice and light tea for the passage of over 2000 ml of urine per day.

• Foods- avoid foods rich in Ca, oxalate or uric acid.