KIDNEY AND DIALYSIS
Role and function of kidneys:
Kidneys are biological marvels and are considered as one of the vital organs for survival. They perform a wide range of functions apart from producing urine. They help in removing the excess water and toxins from the body, produce hormones such as erythropoietin (involved with the production of RBC), regulate mineral levels (Na, K) and blood pressure. They also help in the production of vitamin D and maintain homeostasis (acid/base balance). In a nutshell, the major role of the kidney is to cleanse or purify the blood. If kidneys are damaged or fail to work, the nitrogenous wastes are not filtered out and accumulate in the blood instead. This gives rise to several complications and if left unattended for long may eventually lead to death.
Kidney failure and its types:
Kidney failure can be broadly classified into two types:
- Acute kidney failure- This is marked by the sudden onset of impaired kidney function.
- Chronic kidney failure- This is marked by a gradual decline of kidney function.
There are five stages of chronic kidney disease and the end-stage CKD (Chronic kidney disease) can be life-threatening.
Hallmarks of kidney failure:
- Both acute and chronic kidney failures can be attributed to a lack of fluid in the blood. For this reason, intravenous administration of fluids is recommended. It can also be due to an increase in the amount of fluid, which leads to the swelling of legs and leg cramps due to the toxic accumulation of waste products. For this, diuretics are recommended for the efflux of extra fluid.
- High potassium levels are indicative of kidney disease. Several medications are recommended by nephrologists and administered like glucose or sodium polystyrene sulfonate to combat the toxic accumulation of potassium.
- High creatinine levels in the blood can be indicative of CKD, kidney stones, or glomerulonephritis. The normal range of creatinine is between
0.7 to 1.2 mg/dl in males and 0.5 to 1.0 mg/dl in females. Anything outside that range is considered a red flag.
- GFR (Glomerular filtration rate) level lower than 15mL/min is considered to be serious. This is commonly seen in end-stage CKD. Dialysis is usually recommended at this stage.
Dialysis or artificial kidney:
Filtration of urine artificially other than the kidney is known as dialysis. The most widely used form of dialysis is known as hemodialysis. The other is peritoneal dialysis.
Haemodialysis: It is a renal replacement therapy where the blood is filtered outside the body. At the center of hemodialysis, is a dialysis filter known as a dialyzer serving as an artificial kidney. It cleanses the patient’s blood during treatment. As the blood cleansing process occurs inside the dialyzer, a dialysis machine pumps the blood, administers anticoagulants, and monitors circulation.
- Once inside the machine, blood flows in tiny tubes surrounded by dialysis solution, (called dialysate).The walls of the tube act as a semipermeable membrane that allows only small molecules like water, nitrogenous waste, electrolytes to pass through. The filtration occurs employing osmosis and diffusion. Water solutes movies from the region of higher concentration to a region of lower concentration.
- The dialysis fluid contains solutes at a level similar to that of blood. Urea, potassium, and other solutes in the patient’s blood move out to dialysate which is constantly replaced and discarded. The waste products pass out from the blood
into the dialyzing fluid by diffusion. The purified blood is pumped back to the vein of the patient which is connected to the other end of the dialysis device. This mimics the reabsorption process that takes place in the kidney, particularly in the renal tubules.
- Along with the removal of toxic wastes, simultaneous addition of other substances also follows. For instance, bicarbonate is added to adjust the patient’s blood pH, erythropoietin is added to compensate for its low production by impaired kidneys, anticoagulants like heparin are added to prevent blood clotting (which might arise due to the contact of the patient’s blood with foreign artificial surfaces).
- One-time minor surgery is performed before the dialysis to create vascular access, which is essentially a vein strong enough to withstand the high flow rate through the machine. In some cases, a fistula is formed by fusion of artery and vein or catheter for temporary access. Catheters are used in emergencies.
- Haemodialysis is recommended 3 times per week and is a roughly 4 hours process.
Peritoneal dialysis: In this form of dialysis, the blood is filtered inside the body. The dialysis fluid is introduced to the abdominal cavity via a catheter.
- The lining of the abdomen (peritoneum) serves as a natural filtrating membrane The fluid remains in the body for several hours allowing the exchange of the blood before being discarded.
- There are two subtypes of peritoneal dialysis. Continuous ambulatory peritoneal dialysis( 4 exchanges/day) and automated peritoneal dialysis which last for 7 to 8 hours and can be done as per convenience, for instance at night while sleeping.
- It is less effective than hemodialysis. It can be performed for a longer period, is better to tolerate, is less expensive, and is more flexible.
- The exchange process takes place for 30 minutes.
The cost involved with dialysis: The average cost of dialysis in India varies depending on the location of the health care center or hospitals but is approximately between 12000 to 15000 INR (monthly dialysis expenditure excluding medications).
Benefits of Dialysis: The following are the benefits of dialysis if performed regularly (3 times a week).
- Better quality of life.
- Increased chances of survival.
- Fewer complications.
However, the burden and pain associated with dialysis outweigh the benefits it provides. Some associated problems are itching (owing to phosphorus deposition in the body), the elevation of B.P (blood pressure), leg cramps, dryness of skin, and neuropathy. Moreover, dialysis necessitates frequent hospital visits which impacts the quality of life of the patients. So patients sometimes opt for renal transplantation for permanent relief. Moreover, it increases the life expectancy of the patients.
Recommendations for patients undergoing dialysis:
- A high protein diet (eggs and green veggies) needs to be consumed.
- Consumption of foods having low sodium potassium content is an absolute prerequisite for maintaining the healthy status of the kidney.
- Balanced consumption of fluids and beverages is recommended. ,
- Cauliflower, blueberries (antioxidants), eggs, garlic(instead of salt), onions, and pineapples are mandated dietary intakes.
- The serum potassium, calcium, creatinine, urea levels need to be checked regularly.
- Traveling is not recommended as dialysis might be skipped. Regular dialysis (3 times a week) at a recognized health center, is an absolute prerequisite for restoring the function of the kidney.
- Support and care are required from both health care professionals and family members. Family members must undergo additional training for operating and using dialysis machines at home. This is pertinent for patients on the peritoneal mode of dialysis.
Conclusion: If the aforementioned steps are followed it can improve the quality of life and the life expectancy of the patients with kidney disease.