Electrolytes Flashcards
Electrolytes
substances whose molecules dissociate into ions when placed in water
Cations
Positively charged ions
Anions
Negatively charged ions
Milliequivalents
unit of chemical activity
Faraday’s Law of Electrical Neutrality
154 mEq/l of cations = 154 mEq/l of anions if a (+) is lost, a (+) must be reabsorbed or a (-) must be lost
nutritional recovery syndrome
when there is not enough minerals to keep up with the body’s demand to make new cells
Anion Gap
Difference between the sum of cations (Na+ and K+) and the sum of anions (Cl- and HCO3-)
reflects unmeasured ions in the plasma
Used to determine the cause of metabolic acidosis
Normal Anion Gap Levels
8-16 mEq/l if K+ is used
8-12 mEq/l if K+ not used
Increase in Anion Gap
metabolic acidosis due to lactic acidosis
Normal Anion Gap
metabolic acidosis due to decrease K+ (renal tubular acidosis) or increased loss of anions (diarrhea) or diabetic ketoacidosis (most common)
Decrease in Anion Gap
metabolic acidosis due to hypoalbuminemia
What is main extracellular cation
Sodium (Na+)
functions of Na+
regulate ADH secretion
fluid control
conduction of neurological impulses
If you have an Na+ imbalance you likely have…
K+ imbalance
Normal Na+ level
135-145 mEq
Hyponatremia
< 135 mEq of Na+
Causes of hyponatremia
loss of Na+ dilution of serum Na+ salt restricted diet low aldosterone increase in ADH diuretics burns Water enemas
signs and symptoms of hyponatremia
muscle weakness anorexia nausea, vomiting, diarrhea fatigue apathy headache vertigo
if hypovolemic–poor skin turgor, low blood pressure, increased heart rate
if euvolemia/hypervolemic–increased heart rate, normal/increased blood pressure
treatment for hyponatremia
replace Na+ IV of normal saline (0.9%) if level < 120 in peds or < 115 in adults give 3% to 5% Na via IV piggyback for mild cases uses diet therapy diuretics PRN
Hypernatremia
> 145 mEq of Na+
Causes of Hypernatremia
lose more water that Na+ renal failure heart failure increased aldosterone decrease in PO fluids increase in Na+ PO or IV
signs and symptoms of Hypernatremia
if hypovolemic–dry sticky mucous membranes, nausea, thirst, rubbery tissue turgor, flushed skin, increase in temperature, decreased blood pressure, decreased urine output, increased heart rate, rough and dry tongue
if euvolemic/hypervolemic–normal or increased blood pressure, peripheral and pulmonary edema, weight gain, restlessness, agitation intense thirst
treatment of Hypernatremia
treat underlying cause
restrict Na+ intake
diuretics PRN
Normal K+ levels
3.5-5.5 mEq
principle intracellular cations
K+
functions of K+
neuromuscular activity
acid/base regulation
transport glucose into cell
hypokalemia
< 3.5 mEq of K+
causes of hypokalemia
GI loss diuretics increased aldosterone exogenous steroids inadequate intake stress polyuria alkalosis
signs and symptoms of hypokalemia
anorexia nausea and vomiting decreased bowel sounds distended abdomen paralytic ileus muscle weakness malaise polyuria shallow, increased respirations weak thready pulse dysrhythmias flat/inverted T wave
treatment for hypokalemia
IV or PO K+
(oral K+ is irritating to GI–give with food)
never give > 10-20 mEq/hr/IV without cardiac monitoring–watch urine output (do not give if < 400 cc/24 hours)–never give IV push, always IV piggyback
hyperkalemia
> 5.5 mEq of K+
causes of hyperkalemia
shock burns trauma (anything that causes cell death) renal failure adrenal insuffiency stored blood acidosis salt substitutes K+ sparing diuretics venipuncture (pseudohyperkalemia)
signs and symptoms of hyperkalemia
diarrhea and abdominal cramps nausea arrhythmias (bradycardia) oliguria general muscle weakness and cramps paresthesia of extremities peaked T wave and prolonged QRS
treatment of hyperkalemia
kayexalate PO or rectal enema hypertonic glucose IV with insulin IV sodium bicarb inhaled beta-2 agonists (albuterol) dialysis 10% Calcium Gluconate IV
normal calcium levels
4.5-5.8 mEq or 9-11mg/dL