Overview  Blood Urea Nitrogen (BUN)  Normal Value Range Pathophysiology Special Considerations Elevated Values Decreased Values    Nursing Points General  Normal value range  7-20 mg/dL   Pathophysiology  Protein broken into amino acids -> Ammonia Ammonia converted to urea Urea excreted via kidneys   Special considerations  Green top tube Submitted in multiple panels  Chem 7/Chem 10 CMP Renal panel     Elevated values  Renal failure Congestive heart failure Myocardial infarction Dehydration Urinary obstruction Diabetes   Decreased values  Liver failure Overhydration Inadequate protein intake  Malnutrition   Pregnancy    Assessment  Assess patient’s nutritional status Assess urine output Find primary cause for renal impairment (pre-/intra-/post-renal)  Therapeutic Management  Treat cause of renal insufficiency  Dialysis vs medication    Nursing Concepts  Lab Values Elimination 

Blood Urea Nitrogen (BUN) Lab Values

By Jon Haws RN: Critical Care Nurse NCLEX Educator

Quick . . . is the aPTT within normal range? Are you sweating a bit? Nervous? Head over to NURSING.com/freebies for our free cheat sheet covering the 63 most important lab values for nurses. This podcast covers one essential lab value for episode including normal ranges, nursing considerations, and background information. Normal lab values are hard to keep straight. This show includes the most common including: Creatinine, WBC, BUN, aPTT, blood gasses, and more. Welcome to the Nursing family! For full disclaimer information visit nursing.com.

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Normal <150 mg/dL  Indications  Evaluate for:  Elevated triglycerides Risk for atherosclerotic heart disease and stroke     Description Triglycerides (TG) are required to provide energy during the metabolic process, excess triglycerides are stored in adipose tissue.  What would cause increased levels?  Myocardial Infarction (MI) Alcoholism Alcoholic cirrhosis High carbohydrate diet Anorexia nervosa Cirrhosis Hypertension (HTN) Nephrotic Syndrome Obesity Renal failure Pancreatitis Stress   What would cause decreased levels?  Chronic Obstructive Pulmonary Disease (COPD) Liver disease Hyperthyroidism Malnutrition Malabsorption 

Triglycerides (TG) Lab Values

Normal 135-145 mEq/L  Indications  Monitor: Extracellular osmolality Electrolyte imbalance   Description Sodium (Na+) is the most abundant cation in extracellular fluid. Sodium aids in osmotic pressure, renal retention and excretion of water, acid-base balance, regulation of other cations and anions in the body. Sodium plays a role in blood pressure regulation and stimulation of neuromuscular reactions. Sodium and water have a direct relationship; water follows salt.  What would cause increased levels?  Cushing Syndrome Hyperaldosteronism Dehydration Burn injury Azotemia (elevated nitrogen) Lactic acidosis (LA) Fever/excessive sweating Excessive IV fluids containing sodium Diabetes Insipidus Osmotic diuresis   What would cause decreased levels?  Congestive Heart Failure (CHF) Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Cystic Fibrosis Diuretic use Metabolic acidosis Addison’s Disease Nephrotic Syndrome Vomiting Diarrhea Ascites Excessive Antidiuretic Hormone(ADH) Liver failure 

Sodium (Na+) Lab Values

Normal 3.5 - 5.0 mEq/L  Indications  Evaluate:  Electrolyte imbalances Cardiac arrhythmias   Monitor patients who are:  Acidotic Receiving diuretic therapy     Description Potassium (K+) is the most abundant intracellular cation and plays a vital role in the transmission of electrical impulses in cardiac and skeletal muscle. It plays a role in acid base equilibrium. In states of acidosis hydrogen will enter the cell which will force potassium out of the cell. A 0.1 decrease in pH will cause a 0.5 increase in K+.  What would cause increased levels?  Renal failure Hypoaldosteronism Addison’s disease Injury to tissues Diabetes Mellitus (DM) Ketoacidosis Hyperventilation Acidosis Infection Dehydration Burns   What would cause decreased levels?  Hyperaldosteronism Excess insulin Alkalosis Diarrhea Vomiting Cystic Fibrosis Cushing Syndrome 

Potassium (K+) Lab Values

Normal 25 - 35 seconds  Indications  Detection of coagulation disorders Evaluate response to Heparin (PT for Coumadin) Preoperative assessment   Description Partial Thromboplastin Time (PTT)evaluates the function of factors I, II, V, VIII, IX, X, XI, and XII. PTT represents the amount of time required for a fibrin clot to form. Monitors therapeutic ranges for people taking Heparin.  What would cause increased levels?  Disseminated Intravascular Coagulation (DIC) Clotting Factor Deficiencies:  Hypofibrinogenemia Von Willebrand Disease Hemophilia   Liver disease:  Cirrhosis   Vitamin K deficiency Polycythemia Dialysis   What would cause decreased levels?  N/A 

Partial Thromboplastin Time (PTT) Lab Values

Normal 95 - 100%  Indications  Determine respiratory status Part of Arterial Blood Gas (ABG) testing   Description Oxygen saturation (SaO2) is a measurement of the percentage of how much hemoglobin is saturated with oxygen. Oxygen is transported in the blood in two ways: oxygen dissolved in blood plasma (pO2) and oxygen bound to hemoglobin (SaO2). About 97% of oxygen is bound to hemoglobin while 3% is dissolved in plasma. SaO2 and pO2 have direct relationships, if one is decreased so is the other. The relationship between oxygen saturation (SaO2) and partial pressure O2 (PaO2) is referred to as the oxyhemoglobin (HbO2) dissociation curve. SaO2 of about 90% is associated with PaO2 of about 60 mmHg.  What would cause increased levels?  Polycythemia Increased inspired O2 Hyperventilation   What would cause decreased levels?  Anemia’s Hypoventilation Bronchospasm Mucus plugs Atelectasis Pneumothorax Pulmonary edema Adult respiratory distress syndrome 

Blood Urea Nitrogen (BUN) Lab Values

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