Renal Failure Main Functions of the Kidneys

Renal Failure

Main Functions of the Kidneys

The kidneys are bean-shaped organs, 12 centimeters long, which lie at the sides of the spinal column behind the abdominal cavity (Merck 2010). Their main function is to maintain the proper balance of water and minerals in the body. Their other major functions include filtration and elimination of wastes and toxins, regulation of blood pressure and secretion of some hormones. The amount of water taken into the body must match the amount being eliminated. If the balance is not maintained, water will accumulate fast and illness or death may occur. Excess water will dilute the body's electrolyte and inadequate amount will concentrate electrolytes. The kidneys regulate and help maintain the precise concentrations (Merck).

The kidneys' second major function consists of filtration and excretion (Merck 2010). They pass out urea, a main waste product from protein metabolism. Urea moves through the glomerulus and into the tubuluar fluid and leaves the body as urine. Metabolic waste products, such as acids, toxins and drugs are also eliminated through urine (Merck).

A third major function is the regulation of the body's blood pressure (Merck 2010). Blood pressure tends to increase when too little sodium is excreted. The kidneys also produce the enzyme called rennin. They secrete this hormone into the blood stream when blood pressure drops below normal levels. The hormone activates the rennin-angiotensin-aldostrerone system, which responds by raising blood pressure. Persons suffering from kidney failure are likely to have high blood pressure (Merck).

The kidneys secrete other hormones to regulate other important functions like the production of red blood cells and bone growth and maintenance. One such hormone is erythropoietin, which stimulates red blood production in the bone marrow (Merck).

Nursing Assessment of a Patient with Acute Renal Failure

Mrs. Hogan, 30 years old, was admitted to the nursing unit of acute renal failure. When interviewed on her medical history, she relates that she has been relatively in good health and suffered only minor illnesses, such as chicken pox as a little girl (Franz 2009). She has never been hospitalized and has no allergies to any medications. She is not on any medication at present. Physical examinations included a temperature of 97.4 F, pulse rate at 100, and blood pressure at 124/68; pale, cool and dry skin with many scrapes; minor abrasions, and facial bruises. A bruise was noted on her chest and abdomen, marked by the seat belt. Lung sounds are clear, heart tones are normal and abdomen painful. A skeletal traction aligns her right leg. One unit of whole blood was infused into her before admission to the unit. A second is being infused at this time. She has been fitted with a urinary catheter and a nasogastric tube (Franz).

A few hours later, the nurse notices that Mrs. Hogan's hourly urine output fell from 55 to 45 ml to 28 ml (Franz 2009). A fluid challenge consisting of 500 ml, STAT urinalysis; BUN, and serum creatinine, was ordered. It raises the urine output only slightly. Urinalysis shows a specific gravity of 1.010 and the presence of white blood cells, red and white cell casts, and tubular epithelial cells in the sediment. Her BUN is 28 mg/dL and serum creatinine 1.5 mg/DL. The physician's diagnosis is probable acute renal failure. He orders a nephrology examination and consultation, and 10 ml aluminum hydroxide every two hours per nasogastric tube and 50 mg rantidine intravenously every 8 hours (Franz).

Two Potential Problems and Care Plans

The four most common, often called the "fatal four," are aspiration, dehydration, constipation and epileptic seizures (DHS 2008). They occur most frequently among those with developmental disabilities, leading to more severe illness and even death. The first 3 often go unnoticed among disabled persons who are usually unable to communicate their discomfort. And sudden and continuing epileptic seizures increase the risk of hospitalization and even death (DHS).

Aspiration consists of inhaling food, fluid, saliva, medication or another foreign object into the trachea and lungs (DHS 2008). The material can be introduced into the stomach or from the stomach, back to the throat. If the person stops breathing, CPR should be performed and 911 should be called. All feeding should be stopped immediately and restarted when health care professional gives permission. In the meantime, the person should be kept in an upright position and encouraged to cough. In the meantime, a swallowing specialist should be consulted if symptoms show up. A physician's order to change diet consistency, texture or consistency should be obtained. Eating should be done more slowly with small bite sizes. The patient's physical position should be kept upright 45 minutes after meals for 45 minutes. His bed should be elevated 30-45degrees. No food or fluids should be given 2-3 hours before bedtime. Medications to empty the stomach should be considered. An aspiration protocol and written instructions on these matters should be prepared (DHS).

Dehydration happens when fluid intake is insufficient (DHS 2008). The body then loses fluid more than it replaces. If the patient cannot drink safely, a health care professional should be called to administer intravenous fluids. In the meantime, the patient should be encouraged to drink 8-10 glasses of fluid or water every day, according to body weight. If he is reluctant, he may eat foods with high fluid content, such as gelatin, watermelon, puddings, yogurt or ice cream. If he very active, works hard, has a fever or sweats heavily, he needs more fluids. He needs less fluid if he has had cardiac or kidney disease. A health care professional should evaluate a patient with dysphagia. Protocol should include clear instructions on fluid requirements; minimal amount of daily fluid intake; monitoring intake and output; and signs and symptoms (DHS).