THE RENAL SYSTEM AT A GLANCE

Julie, Ashley, Christen, Candace, Jennifer, Sarah, & Cindy

Objectives

BUN• When is it used• Nursing implications• Normal values • Abnormal result

Creatinine• When it is used• Nursing implications• Normal values • Abnormal result

Creatinine Clearance• When it is used• Nursing implications normal values • Abnormal result

Tests for BUN/Creatinine

Renal Diseases/Illnesses

Dialysis Methods

Blood Urea Nitrogen

• Measures the amount of urea nitrogen in the blood• Urea is formed in the liver as the end product of

protein metabolism and digestion• Protein is broken down into amino acids during

ingestion, once in the liver, these amino acids are catabolized and free ammonia is formed.

• Ammonia molecules are combined to form urea, which is then transported by the blood to the kidneys for excretion.

When is BUN Used?

• Used to assess kidney function and liver function as well as glomerular filtration rate.

• Levels reflect the balance between the production and excretion of urea.

• It may also be used to determine if body fluids are urine or not.

Nursing Implications

• Explain procedure to the patient • Provide teaching regarding what the test will

be measuring.• Inform the patient that no fasting is required

with this test.• Monitor puncture site for bleeding

Normal Values

• Normal values for an adult under the age of 90 years old are 2.9-7.5 mmol/L

• For patients over the age of 90, levels are 3.6-11.1 mmol/L

BUN

• Cardiac Patients– Reduced Renal Perfusion– Intravascular Fluid Volume Deficit

• Increase as GFR decreases– ARF– CRF– Dehydration

• Altered Protein intake• Protein Catabolism

Creatinine

• End product of creatine metabolism. • Creatine is an energy-requiring metabolite of the

skeletal muscle. • Creatine is converted to creatinine during metabolism

where it is filtered through the kidney’s and excreted. • Only a small amount of creatine is converted to

creatinine, this level remains stable except when there is damage to skeletal muscle.

• The measuring of creatinine is an indicator of renal function

Indications

• Before administration of nephrotoxix medications, to assess renal function

• Check glomerular function• Monitor effectiveness of renal treatment• Check accuracy of 24 hour urine collection• Assess level of nephron damage

Normal ValuesAge SI Units

Adult male 124-230 umol/kg/24hr

Adult female 97-177 umol/kg/24hr

Nursing Implications

• Inform patient the test if used to assess renal function

• Obtain a detailed history, including medications• Discuss procedure with patient• Instruct patient as to proper procedure for

urine collection.• Discuss with patient the process of a 24 hour

urine collection.

Factors effecting levels

Creatinine • Extremes of age and body size• Severe malnutrition or obesity• Disease of skeletal muscle• Paraplegia or quadriplegia• Vegetarian diet• Rapidly changing kidney function• Pregnancy

Creatinine

• Increased In:– Nephritis – Chronic Renal Disease

• Decreased In:– Muscular Atrophy– Anemia– Advanced Degeneration of the Kidneys

Creatinine Clearance

• Diagnostic test of renal function• Compares the amount of creatinine in a

blood sample and urine sample to determine rate the kidneys are clearing creatinine from the blood

• Measure of glomerular filtration rate

Indications

• Determine extent of nephron damage in known renal disease

• Before administering nephrotoxic drugs• Accuracy of 24-hr urine collection• Assess glomerular function• Effectiveness renal disease treatment

Normal Values

• Adult male 85-125mL/min/1.73 m• Adult female 75-115mL/min/1.73 m • Each decade after 40 y decrease of 6-7

mL/min/m (conventional units x 0.0167)

abnormal result

• Degree of impairment:– Borderline: 62.5-80 mL/min/m– Slight: 52-62.5 mL/min/m– Mild: 42-52 mL/min/m– Moderate: 28-42 mL/min/m– Marked: Less than 28 mL/min/m

2

Nursing Implications

• Inform patient of test• Obtain pt. genitourinary history & results of

related tests/procedures• Obtain list of medications pt. taking• Review procedure• Inform pt. urine timeframe of urine collection & to

void all urine in collection device• Sensitivity to social & cultural issues

Creatinine Clearance

• Decreased In: – Kidney Diseases

• Acute Renal Failure• Chronic Renal Failure

• Increased In:– Diabetes– Renal Artery Obstruction– Renal Vein Thrombosis– Glomularulonephritis– Nephritis

Tests For...

Creatinine• Blood/serum:

– Serum (about 1mL) collected in a red or tiger- top tube. Or

– Plasma collected in green- top (heparin) tube is also acceptable

• Urine:– Urine (5mL) collected from an

unpreserved random or timed specimen – needs to be collected in a clean plastic collection container

BUN• Blood/serum:

– Serum (about 1mL) collected in a red or tiger- top tube. Or

– Plasma collected in green- top (heparin) tube is also acceptable

How to Test...

Blood Urine

Random Specimen

Clean Catch• Female client procedure• Male client procedure

Timed• Obtain a 3L urine specimen

container, toilet-mounted collection device and a plastic bag for transporting the specimen container

Dialysis

• When your kidney’s cannot adequately remove waste from your body dialysis may be implemented

• Pts can survive on dialysis for years• The only way to stop dialysis (and still survive)

is to have a kidney transplant

Why Have Dialysis?

Because it treats:• Renal Failure • Edema• Hepatic coma • Hyperkalemia• Hypercalcemia• Hypertension• Uremia• Fluid overload• Pulmonary edema• Acidosis• Pericarditis• Severe confusion

There are 2 Types of Dialysis

Hemodialysis Periotoneal Dialysis

Hemodialysis

• Hemodialysis works to – remove toxins (N) & excess water from the blood

stream– maintain and restore the electrolyte balance &

acid-base buffer system (done in the dialyzer)– have ‘clean’ or filtered blood re enter the body as

it would when leaving the kidney

Dialyzer

The blood filtering device

• Filtration through:• Diffusion – how the

toxins are removed • Osmosis – takes away

extra water• Ultrafiltration – takes

away extra water

Complications• Artheriosclerotic cardiovascular

disease• Hypertriglyceridema• Amemia• Fatigue• Gastric ulcer• Fluid overload • Exsangulation• Hypotension• Muscle cramping• Air emboli • Dysrythmia• Chest pain• Cerebral fluid shifts

Peritoneal Dialysis• Peritoneal dialysis is implemented to...– Remove the toxic fluids – Remove metabolic wastes – Re-establish normal fluid and electrolyte balance.

Who needs treatment?Who should not receive this

treatment?How to patients receive this treatment?

How does this effect a patient receiving this treatment?

Complications

• Peritonitis• Leakage• Bleeding• Hypertriglyceridemia• Abdominal hernias• Clot Formation• Constipation

References• Day, R.A., Paul, P., Williams, B., Smeltzer, S.C. & Bare, B. (2006).

Textbook of medical-surgical nursing. Philadelphia, PA: Lippincott Williams and Wilkins.

• McCance, K.L. & Huether, S.E (2006). Pathophysiology: The biological basis for disease in adults and children. St. Louis, MO: Elsevier Mosby.

• Myers, T. (Ed.). (2006). Mosby’s dictionary of medicine, nursing and health professions (7th ed.). St. Louis, MO: Mosby Elsevier.

• Pagana, K.D. & Pagana, T.J. (2010). Mosby’s manual of diagnostic and laboratory tests (4th ed.) St. Louis, MO: Mosby’s Elsevier Inc.

• Van Leeuwen, A.M, Kranpitz, T.R and Smith, L. (2006). Davis’s comprehensive handbook of laboratory and diagnostic tests with nursing implications (2nd ed.). Philadelphia, PA: F.A Davis Company.