Electrolyte

Nursing Bsn with Me at University of Southern Nevada

About this deck

By: jam walker
Created: 2011-02-01
Size: 42 flashcards
Views: 14

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Amount of water (% body weight)

70-80% in infants; 50-60% in adults; 45-55% in older adults

Prevalent cation in the ICF

potassium

Prevalent anion in the ICF

phosphate

Prevalent cation in the ECF

sodium

Prevalent anion in the ECF

chloride

osmotic pressure

Amount of pressure required to stop osmotic flow of water; Determined by the concentration of solutes in the solution.

Hydrostatic pressure

Force within the fluid compartment; force that pushes water out of the vascular system.

Oncotic pressure

Osmotic pressure exerted by colloids in solution (such as protein).

Causes of plasma-to-interstitial fluid shift.

(1) Elevation of hydrostatic pressure.
(2) Decrease in plasma oncotic pressure.
(3) Elevation of interstitial oncotic pressure.

Causes of interstitial-to-plasma fluid shift.

Increased plasma osmotic or oncotic pressure.

"First Spacing"

Normal distribution of fluid in ICF and ECF

"Second Spacing"

Abnormal accumulation of interstitial fluid (edema).

"Third Spacing"

Fluid accumulation in part of body where it is not easily exchanged with ECF.

Hypothalamic regulation of water balance.

Osmoreceptors in hypothalamus sense fluid deficit; stimulate thirst and ADH release; result in increased free water and decreased plasma osmolarity.

Pituitary regulation of water balance.

Posterior pituitary releases ADH; also induced by stress nausea, nicotine, and morphine.

Adrenal cortical regulation of water balance.

Releases glucocorticoids (cortisol) and mineralocorticoids (aldosterone) when stimulated by ACTH or Ang II, respectively.

Renal regulation of fluid balance.

Selective reabsorption of water/electrolytes; site of ADH and aldosterone action.

Cardiac regulation of fluid balance.

Natriuretic peptides (ANP) produced by cardiomyocytes in response to increased atrial pressure. ANP antagonizes the RAAS pathway by suppressing secretion of aldosterone, renin, and ADH.

GI regulation of fluid balance.

Elimination of small amounts of water by GI tract; diarrhea and vomiting can lead to significant losses.

Insensible water loss

Invisible vaporization from lungs and skin; about 600-900mL/day.

Gerontological considerations for fluid balance.

(1) Decreased ability to conserve water by kidneys.
(2) Decreased ADH and ANP.
(3) Loss of subcutaneous tissue and moisture.
(4) Reduced thirst mechanisms.

S/S of fluid volume excess

(1) headache, confusion, lethargy
(2) peripheral edema, JVD, bounding pulse, inc BP
(3) dyspnea, crackles, pulmonary edema
(4) polyuria
(5) seizures, coma

Causes of fluid retention leading to fluid volume excess

heart failure, renal failure, SIADH, Cushings, etc.

Treatment for fluid volume excess

(1) diuretics
(2) fluid restriction
(3) sodium restriction
(4) paracentisis (extreme)

Causes of fluid volume deficit

(1) abnormal loss of body fluids (e.g. diarrhea, vomiting, hemorrhage, etc)
(2) inadequate fluid intake
(3) plasma-to-interstitial fluid shift ("3rd spacing")

S/S of fluid volume deficit

(1) restless, drowsy, lethargic, confused
(2) thirst, dry mouth
(3) decreased skin turgor
(4) decreased capillary refill
(5) postural hypotension, inc pulse, dec CVP
(6) dec UOP, inc urine concentration
(7) inc respiratory rate
(8) weight loss
(9) seizure, coma

Interventions for fluid volume deficit

- replace fluids and electrolytes with isotonic IV solution (e.g. LR, NS, blood, etc.)

Sodium: Normal Lab Value

135-145 mEq/L

Causes of hypernatremia

(1) water deficit
(2) inc sodium intake
(3) dec sodium excretion (aldosterone mechanism)

Treatment for hypernatremia

(1) prevent continued water loss by replacing fluids
(2) dilute sodium with hypotonic saline (0.45%NaCl) or D5W
(3) promote excretion of excess sodium w/diuretics

S/S of hypernatremia

(1) restless, agitated, twitching
(2) thirst
(3) flushed skin
(4) also may be symptoms of fluid excess or deficit

Causes of hyponatremia

(1) loss of sodium-containing fluids (GI, sweat, urine)
(2) water excess (sodium dilution)

S/S of hyponatremia

- first manifested in the CNS; similar to those of hypernatremia

Interventions for hyponatremia

(1) fluid restriction
(2) hypertonic saline solution IV (3% NaCl)

Potassium: Normal Lab Value

3.5-5.0 mEq/L

Causes of hyperkalemia

(1) inc intake (e.g. potassium-containing salt substitute)
(2) impaired renal excretion of K+ (most common)
(3) shift of K+ from ICF to ECF (e.g. w/ burn or crush injury; inc tissue catabolism; also metabolic acidosis)

S/S of hyperkalemia

(1) irritable, anxious
(2) weakness, paresthesias
(3) abdominal cramping, diarrhea
(4) irregular pulse, cardiac arrest
(5) ECG changes associated with increased excitability (Vfib, wide QRS, long PR, ST depression)

Interventions for hyperkalemia

(1) dec intake
(2) inc elimination of K+ (kayexalate, dialysis, fluid intake)
(3) IV insulin to force ECF-->ICF movement of K+

Causes of hypokalemia

(1) abnormal K+ loss (diuresis, esp via aldosterone mech)
(2) shift of K+ from ECF to ICF (e.g. in metabolic acidosis or new cell formation)
(3) rarely, deficient dietary intake of K+

S/S of hypokalemia

(1) associate with decreased excitability of nerve/muscle cells
(2) ECG changes: increased P, flattened T, brady, enhanced digoxin toxicity, ventricular arrhythmias
(3) fatigue, weakness, leg cramps
(4) nausea, vomiting, paralytic ileus
(5) paresthesias, decreased reflexes
(6) polyuria, hyperglycemia

Interventions for hypokalemia

- administer KCl supplements (if UOP is >0.5mL/kg)
- IV fluid should be less than 10-20mEq/hr to prevent cardiac arrest

Calcium: Normal Lab Value

4.5-5.5 mEq/L

About this deck

By: jam walker
Created: 2011-02-01
Size: 42 flashcards
Views: 14

About StudyBlue

“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy