Electrolytes Flashcards
1
Q
Electrolytes
A
substances whose molecules dissociate into ions when placed in water
2
Q
Cations
A
Positively charged ions
3
Q
Anions
A
Negatively charged ions
4
Q
Milliequivalents
A
unit of chemical activity
5
Q
Faraday’s Law of Electrical Neutrality
A
154 mEq/l of cations = 154 mEq/l of anions if a (+) is lost, a (+) must be reabsorbed or a (-) must be lost
6
Q
nutritional recovery syndrome
A
when there is not enough minerals to keep up with the body’s demand to make new cells
7
Q
Anion Gap
A
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
8
Q
Normal Anion Gap Levels
A
8-16 mEq/l if K+ is used
8-12 mEq/l if K+ not used
9
Q
Increase in Anion Gap
A
metabolic acidosis due to lactic acidosis
10
Q
Normal Anion Gap
A
metabolic acidosis due to decrease K+ (renal tubular acidosis) or increased loss of anions (diarrhea) or diabetic ketoacidosis (most common)
11
Q
Decrease in Anion Gap
A
metabolic acidosis due to hypoalbuminemia
12
Q
What is main extracellular cation
A
Sodium (Na+)
13
Q
functions of Na+
A
regulate ADH secretion
fluid control
conduction of neurological impulses
14
Q
If you have an Na+ imbalance you likely have…
A
K+ imbalance
15
Q
Normal Na+ level
A
135-145 mEq
16
Q
Hyponatremia
A
< 135 mEq of Na+
17
Q
Causes of hyponatremia
A
loss of Na+ dilution of serum Na+ salt restricted diet low aldosterone increase in ADH diuretics burns Water enemas
18
Q
signs and symptoms of hyponatremia
A
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
19
Q
treatment for hyponatremia
A
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
20
Q
Hypernatremia
A
> 145 mEq of Na+
21
Q
Causes of Hypernatremia
A
lose more water that Na+ renal failure heart failure increased aldosterone decrease in PO fluids increase in Na+ PO or IV
22
Q
signs and symptoms of Hypernatremia
A
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
23
Q
treatment of Hypernatremia
A
treat underlying cause
restrict Na+ intake
diuretics PRN
24
Q
Normal K+ levels
A
3.5-5.5 mEq
25
principle intracellular cations
K+
26
functions of K+
neuromuscular activity
acid/base regulation
transport glucose into cell
27
hypokalemia
< 3.5 mEq of K+
28
causes of hypokalemia
```
GI loss
diuretics
increased aldosterone
exogenous steroids
inadequate intake
stress
polyuria
alkalosis
```
29
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
```
30
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
31
hyperkalemia
> 5.5 mEq of K+
32
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)
```
33
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
```
34
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
```
35
normal calcium levels
4.5-5.8 mEq or 9-11mg/dL
36
3 forms of Ca++ in body
ionized
bound to albumin
bones/teeth
37
functions of Ca++ in body
needed for clotting
38
What is needed for Ca++ absorption?
Vitamin D and PTH hormone
39
What does Ca++ have an inverse relationship with?
phosphorus
40
hypocalcemia
< 9 mg
41
causes of hypocalcemia
```
decreased intake
decrease in Vitamin D
decreased PTH
chronic pancreatitis
small bowel disease
excess renal loss
```
42
signs and symptoms of hypocalcemia
```
tetany--painful, muscle spasms
Trousseau's Sign (carpal spasm)
Chvostek's Sign (facial nerve)
increased deep tendon reflexes
hyperactive abdomen
altered mentation
increased bleeding and bruising
dry, brittle hair and nails
fractures (if deficit persists)
```
43
Why should Ca++ levels be monitored closely after thyroid surgery?
parathyroid glad may have been damaged or removed accidently
44
treatment of hypocalcemia
mild--increase Ca++ in diet, vitamin D and Ca++ supplements
| severe--seizure precautions, Ca++ gluconate IV, thiazide diuretics (decreases urinary loss)
45
hypercalcemia
> 11 mg
46
causes of hypercalcemia
```
excess Ca++ intake
increases Vitamin D intake
increase in PTH
renal disease
prolonged bed rest
bone cancer
steroid intake
thiazide diuretics
```
47
signs and symptoms of hypercalcemia
```
decreased neuromuscular activity
decreased deep tendon reflexes
nausea & vomiting (due to decreased GI motility)
muscle fatigue
constipation
thirst
polyuria
deep bone pain if bone resorption is a problem
fractures
```
48
treatment for hypercalcemia
```
IV saline (promotes Ca++ excretion)
loop diuretics
IV or PO phosphorus
calcitonin (drive Ca++ into bone)
force fluids (3-4 L/day)
low Ca++ diet
weight bearing activities
prednisone (decrease Ca++ absorption in GI)
parathyroidectomy
```
49
normal magnesium levels
1.5-2.0 mEq or 1.7-2.6 mg
50
where is Mg++ in the body?
3 forms
50-60% in bone combined with calcium and phosphorus
30% bound to protein
51
function of Mg++
role in enzyme activity
role in metabolism of fats, carbohydrates and proteins
integrity of neuromuscular system
regulates HPO4- levels
52
hypomagnesemia
< 1.5 mEq of Mg++
53
causes of hypomagnesemia
```
poor nutrition (alcoholism)
GI loss
renal loss due to nephritis
severe, prolonged diarrhea
decrease PTH
diuretics
malabsorption
prolonged TPN
osmotic diuresis due to high glucose levels
```
54
signs and symptoms of hypomagnesemia
```
increase neuromuscular irritability
increased deep tendon reflexes
altered mentation/aggression
increased blood pressure and pulse (related to decreased cardiac function)
nausea, vomiting, diarrhea
```
55
treatment of hypomagnesemia
increased dietary intake
IV MGSO4
seizure precautions
safety issues
56
hypermagnesemia
> 2.0 mEq of Mg++
57
causes of hypermagnesemia
```
antacids & laxatives containing Mg++ with renal failure
overaggressive therapy for low Mg++
epsom salt enemas
diabetic ketoacidosis
rhabdomyolysis
lithium
```
58
signs and symptoms of hypermagnesemia
```
pronounced decrease in neuromuscular function
hypo-reflexes or absent reflexes
decreased respirations
decreased blood pressure
arrhythmias
drowsiness
lethargy
flushing & sensation of warmth
```
59
treatment for hypermagnesemia
```
treat underlying cause
withhold Mg++
promote urinary output using diuretics/fluids
dialysis
IV Calcium gluconate for heart
```
60
Why is hypomagnesemia often associated with hypokalemia?
magnesium is required for Na+/K+ pumps
61
normal phosphorus/phosphate (HPO4-) levels
2.5-4.5 mg/dL or 1.7-2.6 mEq
| will be higher in children
62
What is principle intracellular anion?
phosphate
63
hypophosphatemia
< 2.5 mg of phosphate
64
causes of hypophosphatemia
```
malnutrition
aluminum and/or magnesium antacids
diarrhea
excess laxatives
chronic intestinal disease
diuresis/diuretics
hyperglycemia
rapid TPN administration
excess carbohydrate ingestion/metabolism
```
65
signs and symptoms of hypophosphatemia
```
decreased cardiac function
slow, faint peripheral pulse
skeletal muscle weakness
weak respiratory effort
prolonged bleeding
confusion
tremors
seizures
decreased bone density
renal calculi
```
66
treatment of hypophosphatemia
```
stop phosphorus-binding antacids, diuretics and Ca++ supplements
PO phosphate supplements
foods high in phosphorus
when < 1mg IV
seizure precautions
```
67
hyperphosphatemia
> 4.5 mg/dL of phosphate
68
causes of hyperphosphatemia
```
renal insufficiency
aggressive treatment of neoplasms (chemo)
increase intake
decreased PTH
enemas containing phosphorus (Fleets)
```
69
signs and symptoms of hyperphosphatemia
same as hypocalcemia
| deposition of Ca-phosphate precipitates
70
treatment of hyperphosphatemia
```
management of underlying hypocalcemia
antacids
high calcium diet
decreased phosphate in diet & medications
increase renal excretion
```
71
What is one thing to suspect with TPN administration?
Nutrition Recovery Syndrome
72
How much Ca++ is in a tablespoon of powered milk?
50 mg of Calcium
73
What foods tend to decrease calcium absorption?
foods high in oxalates--spinach, asparagus, rhubarb, almonds, legumes, wheat bran
74
Why does lack of protein decrease Ca++ utilization?
Ca++ is bound to albumin
75
What causes calcium loss via the kidneys?
diet with excess protein and sodium
76
Why can the elderly have a decrease in calcium absorption?
lower HCl acid
77
What foods are high in magnesium?
green, leafy vegetables, whole grains, nuts, bananas, oranges and chocolate
78
What foods are high in phosphorus?
meat, dairy, whole grains, legumes containing phytates (salt form of phosphorus, principle storage in plant tissue) and most carbonated beverages
79
How much potassium is in a teaspoon of salt substitute?
about 50 mEq
80
What are IV rate limits for potassium?
10 mEq/hr via peripheral IV line
20 mEq/hr via central line without monitoring the heart
40 mEq/hr via central line with monitoring heart
81
What are IV concentration limits for potassium?
40 mEq per 100 cc piggy-back
40 mEq per 1000 cc continuous IV bag peripheral
80 mEq per 1000 cc continuous central line
82
What is max amount of potassium that can be give per day via IV?
200 mEq
83
How can burning be eased when giving potassium via IV?
add 10 mg 1% Lidocaine to IV bag
84
What are IV concentration limits for potassium?
40 mEq per 100 cc piggy-back
40 mEq per 1000 cc continuous IV bag peripheral
80 mEq per 1000 cc continuous central line
84
What are IV concentration limits for potassium?
40 mEq per 100 cc piggy-back
40 mEq per 1000 cc continuous IV bag peripheral
80 mEq per 1000 cc continuous central line
85
What is max amount of potassium that can be give per day via IV?
200 mEq
85
What is max amount of potassium that can be give per day via IV?
200 mEq
86
How can burning be eased when giving potassium via IV?
add 10 mg 1% Lidocaine to IV bag
86
How can burning be eased when giving potassium via IV?
add 10 mg 1% Lidocaine to IV bag
