Kidney Function and Renal Failure

• Acute Renal Failure Nursing Care Management

Kidney Function

• The Kidneys are vital organs for fluid and electrolyte balance, blood pressure regulation, waste filtering, and hormone production for red blood cell and bone health.
• Understanding kidney function is crucial for nurses in assessing and managing patients.

Anatomy of the Kidneys

• Kidneys are bean-shaped organs located in the retroperitoneal space in the upper abdominal cavity, one on each side of the spine.
• Each kidney has an outer cortex and inner medulla, containing approximately one million functional units, nephrons.

Micturition

• Micturition is voiding. Filling the bladder stretches activating stretch receptors that signal reflex, contracts the detrusor muscle and conscious relaxation of the external urethral muscle.
• Infants lack control and void 8-10 times a day, while neuromuscular maturation allows control as they age.
• Older adults experience kidney and muscle aging, leading to increased urgency and frequency, loss of bladder elasticity and tone (nocturia and incomplete emptying).
• Kidneys receive approximately 1/5 of cardiac output.

Glomerular Filtration Rate or GFR

• GFR is the volume of blood filtered by the kidneys per unit of time and is directly related to renal perfusion.
• Decreased renal perfusion results in decreased GFR, with GFR naturally declining with age, making it the best indicator of improved kidney function (filtration).

Nephron

• The nephron is the kidney's basic functional unit, crucial in filtration, reabsorption, and urine formation.

Nephron Structure

• The nephron has key components for processing fluid and producing urine.
• Glomerular capillaries are specialized capillaries in the renal corpuscle with a unique structure promoting high hydrostatic pressure for filtration.
• Filtrate with water, electrolytes, and waste moves from the glomerulus into Bowman's capsule
• The proximal tubule follows Bowman's capsule and reabsorbs most of the filtrate back into the bloodstream, including glucose, amino acids, water, and electrolytes.
• The Loop of Henle is a U-shaped nephron portion between the proximal and distal tubules, concentrating filtered fluid.
• Urea enters the Loop of Henle, contributing to urine concentration.
• The distal tubule follows the Loop of Henle, reabsorbing water and sodium, regulated by aldosterone, which influences water and sodium balance.
• Collecting ducts make final adjustments in urine concentration.
• Additional water reabsorption occurs under antidiuretic hormone (ADH), also known as vasopressin.
• Urine, the end product, forms as filtrate undergoes reabsorption and concentration in the nephron.

Filtration

• Filtration of waste products, excess water, electrolytes, and substances from the blood to form in the Glomerulus, a tuft of capillaries within each nephron.

Reabsorption

• Reabsorption of essential substances (glucose, water, electrolytes, and amino acids) from renal tubules back into the bloodstream.
• Renal threshold to reabsorb glucose is a blood glucose (BG) of 180 mg/dL and exceeded glucose appearing in urine.
• The kidney can create glucose from amino acids (gluconeogenesis) and degrades insulin.
• Reabsorption primarily occurs in the proximal convoluted tubule and other nephron segments.

Secretion

• Secretion is moving substances like drugs, toxins, and hydrogen ions from the blood into renal tubules for excretion, primarily in the distal convoluted tubule and collecting ducts.

Fluid and Electrolyte Balance

• Fluid and Electrolyte Balance maintains water and electrolyte levels (sodium, potassium, calcium, and phosphate) and regulates the concentration and volume of urine.

Acid-Base Balance

• Acid-Base Balance regulates acidity by excreting hydrogen ions and reabsorbing bicarbonate ions, maintaining a slightly alkaline pH.

Blood Pressure Regulation

• Blood Pressure Regulation occurs by producing renin, which constricts blood vessels and increases sodium and water absorption via the renin-angiotensin-aldosterone system.

Vitamin D Production and Activation

• Vitamin D Production and Activation involves production and activation, essential for calcium absorption and bone health, it is vital for kidney disease assessment.

Hormone Production

• Hormone Production occurs for Erythropoietin (EPO) and calcitriol (active Vitamin D), essential for red blood cell production and calcium metabolism.
• EPO production occurs through Specialized kidney cells which sense oxygen levels; low oxygen triggers increased EPO production.
• Stimulates proliferation and differentiation of stem cells in the bone marrow and is regulated by oxygen levels, anemia, and hormonal signals

Renal Diagnostic Testing

• Blood creatinine results from muscle and protein breakdown; increases with ≥50% kidney function loss and a prime indicator of damage.
• Blood urea nitrogen (BUN) in the liver is a result of breakdown of protein (by-product is nitrogen), affected by dehydration, infection, chemotherapy, and steriod use.
• BUN elevation suggests kidney disease however, the production of urea is limited as liver failure occurs.
• Glomerular filtration rate (GFR) indicates glomerular function and is calculated from serum creatinine, considering race, age, and gender variables.
• Urinalysis of an early morning specimen allows for urologic disorder detection (color, clarity, concentration/dilution, specific gravity, acidity/alkalinity, drug metabolites, glucose, ketones, protein, leukocytes, nitrites, bacteria).
• Consider the 24-hour urine collection which is used to measure creatinine, urea nitrogen, sodium, chloride, calcium, catecholamines, and proteins to aid mesurement of measurement the glomerular filtration rate.
• KUB refers to Kidneys, Ureters, Bladder X-Ray. It shows the shape, size, and position of the kidneys, ureters, and bladder. May use an injection of contrast dye through the urethra for better visualization and checking for reflux from the bladder back into the kidney.
• Other diagnostic tools include; X-ray, CT, MRI, Ultrasound, Kidney biopsy, Cystscopy (video) and Renal scan of blood flow.

Kidney Dysfunction Consequences

• Kidney function loss over a short time causes include: severe infections, kidney infections, or dehydration and is typically is reversible with prompt treatment.
• Signs and symptoms include: Decreased urine output, Edema (swelling), Fatigue and weakness, Shortness of breath, Nausea and vomiting,Changes in appetite and weight loss, Difficulty concentrating and mental confusion and Electrolyte imbalances

Pyelonephritis

• Pyelonephritis is an infection and inflammation of the kidney pelvis, calyces, and medulla, often starting in the lower urinary tract.
• E. coli is the likely organism which impairs filtration, reabsorption, and secretion, while repeated infections can cause scarring.
• Ciprofloxacin antibiotics carry a risk of tendon rupture.
• Common in females ages 20-30, Kidney Stones (frequent), Reflux, Pregnancy.
• Risk for Older males over 65 with prostatitis and hypertrophy of prostate.
• Symptoms: Chills, abdominal pain (colicky), nausea, malaise/fatigue, urinary tract infection symptoms, CVA tenderness (costovertebral angle tenderness), flank and back pain, fever, tachycardia, tachypnea, hypertension, vomiting

Treatment for Pyelonephritis

• UTI is treated with Antibiotics, Antipyretics and Analgesics - treat the underlying case)

Renal Calculi (Urolithiasis)

• Cause is unknown, often composed of calcium phosphate or calcium oxalate, most often in males than females.
• Reoccurrence risk increases if first occurs before age 25
• Root words: Uretero (in the ureter), Pyleo (the kidney pelvis), Nephro (the kidney).
• Symptoms include: severe back/flank pain (renal colic) that intensifies as the calculus moves through the ureter and pain goes into the groin, possibly radiating to the abdomen, scrotum, testes, and vulva as it moves. Red or rusty-colored urine.
• Other symptoms include: Urinary frequency, Diaphoresis, pallor, nausea/vomiting, tachycardia, tachypnea and blood pressure changes. If obstruction occurs an emergency requiring surgery should be done to prevent irreversible damage.

Nephrolithiasis

• Nephrolithiasis is the formation of a stone in kidney
• Ureterolithiasis is the formation of stone in ureter

Treatment

• IV Fluids flush the kidneys
• Medications include: Opioids for severe pain of 24-36 hours onset, NSAIDS for mild to moderate pain and Spasmodics to reduce spasms. For example Oxybutynin and Tamsulosin (Flomax) to allow relaxing of the muscles. Also antibiotics with (gentamicin and cephalexin).
• Strain the urine and consume more than 3 liters of oral fluids daily.
• Possible Lithotripsy , Uterocystoscopic surgery and Surgical stent placement to dilate the ureter and assist passage of calculus, though surgery may be required to remove the stone.
• Severe pain can cause nausea and vomiting, therefore treat the pain and you treat the nauses/vomiting.

Nursing Assessment/Treatments

• Assess for Pain, Urinalysis, BUN, Creatinine (blood and urine), GFR & eGFR and WBCS
• Normal Ranges: BUN 10-20 mg/dL, Creatinine serum 0.5 – 1.3 mg/dL related to age & gender, Hemoglobin 12-18 g/dL related to gender and Potassium 3.5-5.0 mEq/L
• Manifestations are: Abdominal Pain and Confusion which can present with renal calculi or infection or electrolyte imbalances
• Costovertebral Angle (CVA) Tenderness may indicate inflammation or infection and Hematuria is the prescence of blood which is pink or red. Microalbuminuria is the prescence of excessive protein in the urine and Tea-Colored Urine, which indicates Bilirubin.

Laboratory Markers

• Blood Urea Nitrogen (BUN) is a waste product from protein filtered and excreted. Elevated blood urea nitrogen, known as Azotemia = kidney issues. Best indicator of improved kidney function.
• Serum Creatinine is a a breakdown of product of muscle metabolism which is filtered by the kidneys and excreted in urine which is a indicator of kidney function in the glomerular filtration rate (GFR)- Increasing serum.
• Creatinine = decrease of the Glomerular filtration rate.

Nursing Implications

• Conduct a thorough assessment of abdominal pain, urinary changes, and CVA tenderness to identify potential kidney dysfunction.
• Monitor laboratory markers such as BUN and serum creatinine levels to assess renal function.
• Collaborate to initiate appropriate interventions.
• Educated patients on hydration, dietary restrictions, and medications.

Conditions decreasing renal perfusion

• Affects the GFR directly (blood flow is reduced)
  • Hypovolemia is a reduced renal perfusion and oxygen supply to the kidneys, often from fluid loss such as vomiting or hemorraging
• Heart failure, the heart is unable to pump blood effectively, this then results in reduced circulation, decreasing the filtration and urine output in the heart.
• Shock, in its different variations, is characterized by an insufficient blood and oxygen delivery to body tissues or an interruption, compromsing the function of the kidneys

Direct damange to the kidney (Intrarenal)

• Untreated or uncontrolled diabetes and hypertension
• Trauma such as penetration injuries which cause damange and disrupts blood flow

Pyelonephritis

• Infections that occur such as Pyelonephritis which causes inflammation and damage to the kidney tissue which impacts the production of urine

Nephrotoxic Drugs

• Medications may have a toxic effect with the kidneys - NSAIDS and ACE inhibitors

Obstructive Uropathy (Postrenal)

• Refers to conditions that prevent or hinder the noraml flow of kidneys , leading to pressure imbalance, like kidney stones and prostate gland hyperplasia

Hydronephrosis

• Is when a kidney is fluid filled, aka swollen kidney,
• Acute Kidney Injury; the insults to kidnesy which have caused damage and resulting function, the intervetion may restore kidney function
• Common signs are increased levels of aste projects, creatinine, and fluid retention
• Prenal is decreased renal

Prerenal AKI

• Decreases the the renal perfusion Includes Ischemia, hypovolemia (low blood volume) and hemorrahage, like shock

Intrinsic AKI

• It is describeds as damage occuring within the resnal tissue itself
• Nonsteriodald, like aminoglycoside, causes nephro-toxicity
• Consumption of NSAIDS, and infection like acute tubular

Postrenal AKI

• From uropathy, which inpedes the normal outflow of urine from the kidneys
• The result is kidney stones, Prostatic hyperplasia, obstruction , and the stagnant urine leads to being infectious.
• Acute tubular involves hypoxia, which impacts the renal tubules of the kidney

Treatment of AKI

• Involves maintaince and control of blood, electrolytes, blood glucose and monitor of the RBC. Addressing of issues like kidney dysfunction. Prompt involves restoration, and discontinuing of nepho, or medications. Managing of obstructions, use of dialysis.

Initial Insult Phase

• Causes are toxins, dehydration, and reduing blood flow. It may not show symptoms, the trigger should be adressed.

Oluguric Phase

• GFR, and Urine output causes Electrolyte imbalance elevated blood pressure

Diuretic Phase

• Is large outflow on unconcentrated urine, causing elecrolyte imbalance

Recovery Phase

• The kidnety improvves and returns to normal, and appropriate.

Purpose of Dialysis

• Dialysis helps perform the functions of the kidnets when they are unable to do so.
• It helps with function of removing products, concentration, corrects, and removes fluids.

Hemodialysis

• Utilizies a shunt, and is preformed 3 times a week for 4-6 hours to stabilize and normalize blood, albuim, electrolyte and creatinines Risk : Infection, Volume loss, hemorrhaging
• Auscultation to bruit, Thril
• AV Stimulus: The avoidance of injection, or taking BP, is imperative

Before : Vital signs, lab values, weight

Caution

• Disequilibrium : Drop in Blood, Volume, Cerebal edmea

With dialysis be consicderate of naussea, vomiting, LOC, seiuzres, agitaiton, increased risk with age

• Hypotension like fluid depletion is also to consider as its the rate to be exchanged
• Anemia, blood, follicle removals is important to consider to remove fluids

Peritoneal Dialysis

• This means the instillation into a peritoneal cavity

• The intact is required to self - adminster Before adminster - Obtain Dry weight, vitals, creatinine

• It is important to consider the volume of inputs, and the volume of outputs. There may be an infection.

• Peritonis (peritoneum) : Cloudy color, purre drainage, redness and tender. Site may show infections that are purslent and swelling. With all there is an importance to to aseptic the site.

Complications of dialysis include Catheter, Migration And Disequilibrium Syndrome

Pathopsyiolgy

• rapid removal of solutes leads to the brains with delayed clearnace and shift where cerebral edemas and neurological symptoms First time patients, severe levels, need to undergo severe treatment and must monitored frequently. Neurological , vital .

Kidney Transplant

• Tissue of Donar and reciepent need to match This has a good chance of success in most of the patients whom show proper health

There is a large list of criteria that meets this list as it will need medication for health There must be immunosuprresant therapy, and the immune system will be need to be checked

Patients shouold be well tolorate.

Post Op care - Monitor vitals, and patients well bring

It is important to maintain airflow. It requires the ABC Most patients feel well , but it requeries the support of health providers to ensure well bring for the long run.

Explore the functions of the kidneys and indicators of improved function. Learn about filtration, secretion, and electrolyte imbalances in renal failure. Understand hematuria, azotemia, causes of AKI, nephrotoxicity, and phases of acute kidney injury.