fluid and electrolytes

Fluid & Electrolytes: 

Fluid & Electrolytes Nursing 477

Homeostasis : 

Homeostasis Extracellular fluid Intracellular fluid Interstitial fluid Transcellular fluids

Hydrostatic and Oncotic Pressures: 

Hydrostatic and Oncotic Pressures

Clinical Significance: Edema: 

Clinical Significance: Edema Edema develops with changes in normal hydrostatic pressure differences.

“Water goes where salt is….”: 

“Water goes where salt is….”

Electrolyte Content: 

Electrolyte Content Plasma Cations Sodium (Na+) 142 Potassium (K+) 5 Calcium (Ca++) 5 Magnesium (Mg++) 2 Total Cations = 154 Anions Chloride ( Cl -) 103 Bicarb (HCO3-) 26 Sulfate (SO4--) 1 Organic acids 5 Proteinate 16 Total Anions = 154 Intracellular fluid Cations Potassium (K+) 150 Magnesium (Mg++) 40 Sodium (Na+) 10 Total cations =200 Anions Phosphates & Sulfates 150 Bicarb (HCO3-) 10 Proteinate 40 Total anions = 200

Normal Saline = Isotonic: 

Normal Saline = Isotonic Plasma Cations Sodium (Na+) 142 Potassium (K+) 5 Calcium (Ca++) 5 Magnesium (Mg++) 2 Total Cations = 154 Anions Chloride ( Cl -) 103 Bicarb (HCO3-) 26 Sulfate (SO4--) 1 Organic acids 5 Proteinate 16 Total Anions = 154 Normal Saline (.9% NaCl ) Cations Sodium (Na+) 154 Anions Chloride ( Cl -) 154 Total Cations & Anions = 308

LR= Isotonic: 

LR= Isotonic Plasma Cations Sodium (Na+) 142 Potassium (K+) 5 Calcium (Ca++) 5 Magnesium (Mg++) 2 Total Cations = 154 Anions Chloride ( Cl -) 103 Bicarb (HCO3-) 26 Sulfate (SO4--) 1 Organic acids 5 Proteinate 16 Total Anions = 154 Total Cations and Anions = 308 LR Cations Sodium (Na+) 130 Potassium 4 Calcium 3 Magnium 0 Total Cations = 164 Anions Chloride ( Cl -) 109 PLUS 28 mEq of Lactate Total Cations & Anions = 274

Dextrose and Water Solutions: 

Dextrose and Water Solutions D5W roughly isotonic Dextrose metabolized to CO2 and water 1 L of D5W = 170 calories

½ Normal Saline (0.45% ) = Hypotonic: 

½ Normal Saline (0.45% ) = Hypotonic ½ Normal Saline (.45% NaCl ) Cations Sodium (Na+) 77 Anions Chloride ( Cl -) 77 Total Cations & Anions = 154 Intracellular fluid Cations Potassium (K+) 150 Magnesium (Mg++) 40 Sodium (Na+) 10 Total cations =200 Anions Phosphates & Sulfates 150 Bicarb (HCO3-) 10 Proteinate 40 Total anions = 200 Total Cations & Anions = 400

3% or 5% Saline = Hypertonic: 

3% or 5% Saline = Hypertonic 3% saline Cations Sodium (Na+) 513 Anions Chloride ( Cl -) 513 Total Cations & Anions = 1026 Intracellular fluid Cations Potassium (K+) 150 Magnesium (Mg++) 40 Sodium (Na+) 10 Anions Phosphates & Sulfates 150 Bicarb (HCO3-) 10 Proteinate 40 Total Cations & Anions = 400

Colloids: 

Colloids Increase the osmotic pressure in the blood stream – thereby increasing vascular volume Albumin Hydroxyethyl starches ( Hespan ) Dextran Gelatins (in Europe only)

Isotonic Dehydration: 

Isotonic Dehydration L oss of both water and electrolytes Most common type of fluid volume deficit

Treatment: 

Treatment Fluid replacement Fluid challenge tests

Clinical Assessment: 

Clinical Assessment Facial Appearance & Sunken Eyes Moisture in Oral Cavity Thirst Skin turgor Capillary refill Tearing Edema Pulmonary Edema Body temp Pulse Respirations Blood pressure Pulse pressure Orthostatic blood pressure

Fluid Volume Excess: 

Fluid Volume Excess Causes: Renal failure Congestive heart failure Cirrohosis of liver Cushing’s syndrome

Lab Studies pertinent for fluid volume status: 

Lab Studies pertinent for fluid volume status Urine studies Urine specific gravity Urine osmolarity Serum Hematocrit = 40-54%/men, 38-47% for women Serum Creatinine = 0.6 – 1.5 mg/dl BUN = 8-20 mg/ dL Serum osmolality Serum Albumin – 3.5-5.5 g/dL Serum Electrolytes

Regulation of Electrolytes: 

Regulation of Electrolytes Maintaining fluid balance Contributing to acid-base regulation Facilitating enzyme reactions Neuromuscular reactions

Sodium Balance: 

Sodium Balance Maintained by ADH secreted from posterior pituitary Highest concentration of all the electrolytes measured in the serum - but changes not commonly seen because concentrations always correlated with fluid balance - I.e. “Water goes where salt is”

Hyponatremia: 

Hyponatremia Most common reason is excess water in the body - can be caused by Salt-free IV fluids Over use of diuretics Increased ADH (causes increased body water) SIADH Compulsive water drinking/water intoxication Vomiting and diarrhea in young kids if just water replaced and not salt Exercise - heavy persperation Addison’s disease

Hypernatremia: 

Hypernatremia Becomes apparent when not enough water in body to balance increasing sodium levels – either large intake sodium without adequate water or large loss of water without proportional loss of salt Hypertonic tube feedings with H2O supplements DI Inadequate water ingestion

Potassium: 

Potassium Normally exists in the cell (98%) - but small amount needed in serum for neuromuscular and cardiac function Kidneys excrete all the potassium - when a sodium ion is reabsorbed by the body - a potassium or hydrogen ion is excreted

Hyperkalemia: 

Hyperkalemia Common Causes: Renal failure Too much potassium replacement Massive cell destruction (burns, crushing injuries) Associated with metabolic acidosis Severe infection

Hypokalemia: 

Hypokalemia Most commonly results from excessive loss of K+ Diarrhea most common world wide cause Vomiting, gastric suction Diuretics Inadequate intake Alkalosis

3 less commonly checked electrolytes: 

3 less commonly checked electrolytes Calcium Phosphorus Magnesium

Calcium: 

Calcium About half of the serum calcium is bound to albumin Amount in serum small compared to amount in teeth and bones (99%) 2 hormones control blood calcium levels Calcitonin - from thyroid gland - prevents calcium excess in blood PTH - parathyroid gland keeps sufficient calcium in the blood

Hypercalcemia: 

Hypercalcemia False rise from dehydration Increased PTH Metastatic bone disease Immobilization Thiazide diurectics Excessive milk intake (> 3 qts/day) Vitamin D intoxication

Hypocalcemia: 

Hypocalcemia False decrease due to low albumin levels Hypoparathyroidism Early neonatal hypocalcemia Chronic renal disease (serum Phos level increased) Pancreatitis Massive blood transfusions Severe malnutrition

Serum Phosphorus: 

Serum Phosphorus Like calcium, levels controlled by PTH Close relationship to calcium Main intracellular anion (-)

Hyperphosphatemia: 

Hyperphosphatemia Hypoparathyroidism (decreased serum Calcium) Renal failure Increased growth hormone Vitamin D intoxication

Hypophosphatemia: 

Hypophosphatemia Hyperparathyroidism (increased serum Calcium) Diuresis Malnutrition Increased glucose metabolism - carbohydrate loading Antacid abuse

Magnesium: 

Magnesium Present only in very small amounts Most of magnesium combined with calcium and phosphorus in bones Essential for neuromuscular function and activation of enzymes Changes in serum magnesium affect other electrolytes - potassium, calcium and phosphorus

Hypermagnesemia: 

Hypermagnesemia Most common cause = renal failure Too much MOM :)

Hypomagnesemia: 

Hypomagnesemia Usually due to low intake of dietary magnesium over a period of time Alcoholism Chronic malnutrition/ refeeding after starvation Diarrhea Diabetes Hypercalcemia or other complex metabolic disorders