Chapter 6 Fluid Electrolyte And Acid-Base Homeostasis

fluid found inside the cell

2/3rds of the body's water. it is rich in potassium K+, magnesium, phosphate, and proteins

fluid found outside the cell divided into

Interstitial (80% between cells) and Intravascular ( 20% inside the blood vessels) 1/3rd of the body fluid. rich in sodium, chloride, and bicarbonate.

1% of body fluid in peritoneal, pleural, and pericardial cavities

cerebrospinal cavities

fluid in joint spaces, lymph system, eyes, and gastrointestinal tract

hydrostatic push- water and solutes

blood

push fluid from intravascular to interstitial

osmotic pull - water

proteins and electrolytes

pull fluid from interstitial to intravascular

osmotic pressure of two solutions separated by a semipermeable membrane.

3 classifications- isotonic solutions. hypotonic solutions, hypertonic solutions

lower solute concentrations, causing fluids to shift out from intravascular to intracellular

4.5% saline

higher solute concentrations, causing fluids to shift in from intracellular to intravascular

5% dextrose in 0.9% saline, 3% saline

urine

feces

insensible losses (breathing, perspiration, etc

Triggeredby decreased blood volume and increased osmolarity (solute concentration)

Promotesreabsorption of water in the kidneys

Increasesreabsorption of sodium and water in the kidneys

stimulatesrenal vasodilatation and suppresses aldosterone, increasing urinary output

Excess fluidin the interstitial space

Excess fluidin the intravascular space

Excess fluidin the intracellular space

•Manifestations:peripheral edema, periorbital edema, anasarca, cerebral edema, dyspnea,bounding pulse, tachycardia, jugular vein distension, hypertension, polyuria,rapid weight gain, crackles, and bulging fontanelles

•Diagnosis:history, physical examination, daily weights, measurement of intake and output,blood chemistry, urine analysis, and complete blood count

•Treatment:wearing compression stockings, administering diuretics, restricting sodium andfluids, maintaining high Fowler’s position, and hypertonic solutions

•Excessivesodium or water intake

–High-sodiumdiet

–Psychogenicpolydipsia

–Hypertonicfluid administration

–Freewater

–Enteralfeedings

•Inadequatesodium or water elimination

–Hyperaldosteronism

–Cushing’ssyndrome

–Syndromeof inappropriate antidiuretic hormone

–Renalfailure

–Liverfailure

–Heartfailure

uDehydration

uHypovolemiaor fluid volume deficit

uDecreasedfluid in the intravascular space

Excessive fluid or sodiumlosses

Gastrointestinal losses

Excessive diaphoresis

Prolonged hyperventilation

Hemorrhage Nephrosis

Diabetes mellitus

Diabetes insipidus

Burns Open wounds

Ascites

Effusions

Excessive use of diuretics

Osmotic diuresis

Inadequate fluid intake

poor oral intake

inadequate iv fluid replacement

Manifestations:thirst, altered level of consciousness, hypotension, tachycardia, weak and threadypulse, flat jugular veins, dry mucous membranes, decreased skin turgor,oliguria, weight loss, and sunken fontanelles

Diagnosis:history, physical examination, measurements of intake and output, dailyweights, blood chemistry, urine analysis, and complete blood count

uTreatment:indentifyand manage underlying cause along with fluid replacement

important in muscle and neural activity and in acid base and fluid balance
Cations- positively charged

Anions- Negatively charged

•Normal range 135-145mEq/L

•Mostsignificant cation and prevalent electrolyte of extracellular fluid

•Controlsserum osmolality and water balance

•Playsa role in acid-base balance

•Facilitatesmuscles and nerve impulses

•Dietaryintake main source

•Excretedthrough the kidneys and gastrointestinal tract

Sodium > 145 mEq/l, Serum osmolarity increases, results in fluid shifts

Excessive Sodium

excessive sodium ingestion

hypertonic IV saline (3% saline) administration

Cushing's syndrome

corticosteroid use

Deficient Water

decreased water ingestion

loss of thirst sensation

inability to drink water

third spacing

vomiting

diarrhea

excessive sweating

diuretic use

diabetes inspidus

uManifestations:increased temperature, warm and flushed skin, dry and sticky mucous membranes,dysphagia, increased thirst, irritability, agitation, weakness, headache,seizures, lethargy, coma, blood pressure changes, tachycardia, weak and threadypulse, edema, and decreased urine output

uDiagnosis:history, physical examination, blood chemistry, and urine analysis

uTreatment:fluid replacement (oral or hypotonic saline solution) and diuretics

sodium < 135mEq/L, serum osmolality decreases

Deficient Sodium

Diuretic use * Gastrointestinal losses* Excessive sweating*Insufficient aldosterone levels* Adrenal insufficiency * Dietary sodium restrictions

Excessive Water

Hypotonic intravenous saline (0.45% saline) * hyperglycemia* excessive water ingestion * renal failure* syndrome of inappropriate ADH * heart failure

•Manifestations:anorexia, gastrointestinal upset, poor skin turgor, dry mucous membranes, bloodpressure changes, pulse changes, edema, headache, lethargy, confusion,diminished deep tendon reflexes, muscle weakness, seizures, and coma

•Diagnosis:history, physical examination, blood chemistry, and urine analysis

•Treatment:limit fluids and increase dietary sodium

Normal range 98-108 mEq/L

Mineral electrolyte

Majorextracellular anion

Found in gastric secretions, pancreatic juices, bile, and cerebrospinal fluid

Plays a rolein acid-base balance

Dietary intake main source

Excreted through the kidneys

Chloride >108 mEq/L

Causes

Increased chloride intake or exchange: hypernatremia, hypertonic intravenous solution,metabolic acidosis, and hyperkalemia

Decreased chloride excretion: hyperparathyroidism, hyperaldosteronism, and renal failure

Manifestations: reflect the underlying cause

Diagnosis: history, physical examination, blood chemistry, urine analysis, and arterialblood gases

Treatment: identify and manage underlying cause, diuretics, and bicarbonate

Chloride <98 mEq/L

Causes

Decreased chloride intake or exchange: hyponatremia, 5% dextrose in water intravenous solution, water intoxication, and hypokalemia

Increasedchloride excretion: diuretics, vomiting, metabolic alkalosis, and other gastrointestinal losses

Manifestations: reflect theunderlying cause

Diagnosis: history, physical examination, blood chemistry, urine analysis, and arterialblood gases

Treatment: identify andmanage underlying cause, sodium replacement (oral or intravenous), ammoniumchloride, and saline irrigation of gastric tubes

Normal range 3.5-5 mEq/L

The primary intracellular cation

Plays a rolein electrical conduction, acid-base balance, and metabolism

Dietary intake main source

Excreted through the kidneys and gastrointestinal tract

Potassium > 5 mEq/L

Causes

Deficient excretion: renalfailure, Addison’s disease, certain medications, and Gordon’s syndrome

Excessive intake: oral potassiumsupplements, salt substitutes, and rapid intravenous administration of diluted potassium

Increased release from cells: acidosis, blood transfusions, and burns or any other cellular injuries

Manifestions: paresthesia, flaccid paralysis, bradycardia, dysrhythmias, electrocardiogramchanges, cardiac arrest, respiratory depression, abdominal cramping, nausea,and diarrhea

Diagnosis:history, physical examination, blood chemistry, 12-lead electrocardiogram, andarterial blood gas

Treatment: correct acidosis, usually with sodium bicarbonate. Calcium gluconate. Decrease dietary potassium intake. Dialysis. Kayexalate. Intravenous fluids. Potassium-losing diuretics. Insulin

Potassium <3.5 mEq/L

Causes

Excessive loss: vomiting, diarrhea, nasogastric suctioning, fistulas, laxatives, potassium-losingdiuretics, Cushing’s syndrome, and corticosteroids

Deficient intake: malnutrition, extreme dieting, and alcoholism

Increased shift into the cell: alkalosis and insulin excess

Manifestations: muscle weakness, paresthesias,hyporeflexia,leg cramps, weak and irregular pulse, hypotension, dysrhythmias,electrocardiogram changes, decreased bowel sounds, abdominal distension,constipation, ileus, and cardiac arrest

Diagnosis: history, physical examination,blood chemistry, 12-lead electrocardiogram, and arterial blood gas

Treatment: identify and manage underlying cause along with potassium replacement (oral orintravenous)

Normal range 4-5mEq/L

Mostly found in the bone and teeth

Plays a role in blood clotting, hormone secretion, receptor functions, nerve transmission, and muscular contraction

Has inverse relationship with phosphorus

Has synergistic relationship with magnesium

Dietary intake main source

Vitamin D aids absorption

Excreted through the gastrointestinal trace

Regulated by

Vitamin K

Parathyroid hormone

Calcitonin

Calcium > 5mEq/L

Causes:

Increased intake or release: calcium antacids, calcium supplements, cancer,immobilization, corticosteroids, vitamin D deficiency, and hypophosphatemia

Deficit excretion: renal failure, thiazide diuretics, and hyperparathyroidism

Manifestations:dysrhythmias, electrocardiogram changes, personality changes, confusion,decreased memory, headache, lethargy, stupor, coma, muscle weakness, decreased deep tendon reflexes, anorexia, nausea, vomiting, constipation, abdominal pain,pancreatitis, renal calculi, polyuria, and dehydration

Diagnosis:history, physical examination, blood chemistry, and 12-lead electrocardiogram

Treatment: identify and manage underlying cause. manage symptoms. phosphate. increase mobility. calcitonin. intravenous fluids. diuretics

Calcium< 4 mEq/L

Causes

Excessive losses: hypoparathyroidism, renal failure, hyperphosphatemia, alkalosis, pancreatitis, laxatives, diarrhea, and other medications

Deficient intake: decreased dietary intake, alcoholism, absorption disorders, and hypoalbuminemia

Manifestations:dysrhythmias, electrocardiogram changes, increased bleeding tendencies,anxiety, confusion, depression, irritability, fatigue, lethargy, paresthesia,increased deep tendon reflexes, tremors, muscle spasms, seizures, laryngealspasms, increased bowel sounds, abdominal cramping, and positive Trousseau’sand Chvostek’ssign

Diagnosis:history, physical examination, blood chemistry, and 12-lead electrocardiogram

Treatment: identify and manage underlying cause. calcium replacement (oral or intravenous). vitamin D. Phosphorus

Normalrange 2.5-4.5 mg/dL

Mostlyfound in the bones and small amounts are in the bloodstream

Playsa role in bone and tooth mineralization, cellular metabolism, acid-basebalance, and cell membrane formation

Dietaryintake main source

Excretedthrough the kidneys

Phosphorus> 4.5 mg/dL

Causes

Deficientexcretion: renal failure, hypoparathyroidism, adrenal insufficiency,hypothyroidism, and laxatives

Excessiveintake or cellular exchange: cellular damage, hypocalcemia, and acidosis

Manifestations:rarely seen alone

Diagnosis:history, physical examination, and blood chemistry

Treatment: Identify andmanage underlying cause* Aluminumhydroxide or aluminum carbonate *Treathypocalcemia

Phosphorus< 2.5 mg/dL

Causes

Excessiveexcretion or cellular exchange: renal failure, hyperparathyroidism, andalkalosis

Deficientintake: malabsorption, vitamin D deficiency, magnesium and aluminum antacids,alcoholism, and decreased dietary intake

Manifestations:similar to hypercalcemia

Diagnosis:history, physical examination, and blood chemistry

Treatment:

Identify and manage the underlying cause

Phosphorusreplacement (oral or intravenous)

An intravenous at cation

Mostly stored in bone and muscle

Plays a role in muscle and nerve function, cardiac rhythm, immune function, bone strength, blood glucose management, blood pressure, energy metabolism, and protein synthesis

Dietary intake main source

Excreted through the kidneys

Magnesium >2.5 mEg/L

Causes: renal failure, excessive laxative, and antacid use

Manifestation similar to hypercalcemia

Diagnosis history physical examination, and blood chemistry

Treatment diuretics, dialysis, and intravenous calcium

Magnesium < 1.8 mEq/L

Causes inadequate intake, chronic alcoholism, malnutrition, pregnancy, diarrhea, diuretics, and stress

Manifestations similar to hypocalcemia

Diagnosis history physical examination, and blood chemistry

Treatment magnesium replacement

Bicarbonate carbonic acid system ( most significant in ECF)

Phosphate system ( high concentrations ICF )

Hemoglobin system (found in erythrocytes)

Protein system ( most abundant found in both ICF and ECF)

Increased respirations release excess CO2 decreasing acid

Slow respirations release less CO2 increasing acidity

Causes bicarbonate deficit. Intestinal loss, renal loss....... Acid excess, tissue hypoxia resulting in lactic acid build up, ketoacidosis, drugs, toxins, renal retention.