ATI MED SURG MID-TERM EXAM Study Guide 2021

Fluids and electrolyte imbalance

-Signs and symptoms of hypovolemia and dehydration vs. hypervolemia

● Hypovolemia = circulating blood volume is decreased leading to inadequate tissue perfusion

o Signs/symptoms of hypovolemia: Dry mucous membranes, poor skin turgor, excessive thirst,

initial increase in HR to compensate then a decrease, oliguria, anuria, tachycardia, decrease in

BP, lethargy, rapid breathing, confusion, prolonged capillary refill, cold and clammy extremities

● Dehydration = fluid loss / Isotonic dehydration = water and electrolyte loss

o Fluid is lost only from the ECF, including both the plasma and interstitial spaces

o Signs/symptoms of dehydration: Increase in HR, weak peripheral pulses, decrease in BP,

increased respiratory rate, dry and scaly skin, poor skin turgor, dry mucous membranes,

confusion,

low-grade fever, concentrated urine

● Hypervolemia = excessive fluid it the ECF (extracellular fluid space)

o Bounding pulse, difficulty breathing, neck vein distension in the upright position,

dependent edema, elevated BP, weight gain, increased respiratory rate, shallow respirations,

dyspnea, crackles in lungs, skin is cool and pale, headache, skeletal muscle weakness

● dehydration is a condition that occurs when there has been excessive loss of body fluid. the

nursing diagnosis for this is deficient fluid volume

○ de - from, without

○ hydra - water

○ tion - state of being

■ literally, a state of being without water

● hypovolemia refers to decreased fluid volume of the blood.

○ hypo - under, beneath, below, low

○ vol(umen) - volume

○ emia - blood

■ literally, blood volume that is low

-Normal ranges of Na, K, Ca, Mg

● Sodium: 136-145 mEq/L

● Potassium: 3.5-5.0 mEq/L

● Calcium: 9.0-10.5 mgEq/dL

● Phosphorus: 3.0-4.5 mgEq/DL

-Most common signs/sx of hypo/hypercalcemia, hyper/hypokalemia hyper/hyponatremia and hypomagnesemia

● Hyponatremia: serum sodium level below 136

o Behavioral changes resulting from cerebral edema and increased intracranial pressure; sudden

onset of confusion in older adults; general muscle weakness; increased motility causing

nausea, diarrhea and abdominal cramping; bowel sounds are hyperactive (rushes and gurgles

over the splenic flexure in the lower left quadrant; bowel movements are frequent and watery

o Hyponatremia and hypovolemia include a rapid, weak and thready pulse; easily blocked with

light pressure; blood pressure is decreased; central venous pressure is low

o Hyponatremia and hypervolemia include cardiac changes include a full or bounding pulse with

a normal or high blood pressure

● Hypernatremia: serum sodium level 145

o Short attention span and be agitated and confused (normal or decreased fluid volume);

lethargic, drowsy, stuporous and even comatose (fluid overload); muscle twitching and irregular

muscle contrations (mild HN); muscles and nerves are less able to respond to stimulus (severe

HN); decreased contractility because high sodium levels slow the movement of calcium into the

heart cells

▪ Excessive sweating is a common cause of hypernatremia (NCLEX Question)

● Hypomagnesemia: serum magnesium below 1.3 mEq/L

○ hyperactive deep tendon reflexes, numbness and tingling, and painful muscle contractions;

POSTIVE Chveostek’s and Trousseau’s signs with hypocalemia; anorexia, nausea,

constipation, and abdominal distension

● Hypocalcemia: Frequent, painful muscle spasms “charley horses,” paresthesias of hands and feet,

tingling or twitching

● Hypercalcemia: increased heart rate and blood pressure, poor tissue blood flow (cyanosis and

pallor), movement of blood clots, muscle weakness, decreased peristalsis

● Hypokalemia: respiratory weakness resulting in shallow respirations; skeletal muscle weakness;

pulse thready and weak; decreased peristalsis

● Hyperkalemia: Cardiac changes are the most severe for these patients = bradycardia, hypotension,

and ECG changes (peaked T waves, prolonged PR intervals, flat or absent P waves and wides asystole

and ventricular fibrillation)

○ Foods high in potassium include bananas, cantaloupe, kiwi, oranges, avocados, broccoli, dried

beans, lima beans, mushrooms, potatoes, seaweed, soybeans, and spinach.

■ Apples are considered to be low in potassium.

-Most likely causes of hyponatremia, hypokalemia, hyperkalemia, hypercalcemia, and interventions to treat

Hyponatremia causes:

● Actual Sodium Deficits

o Excessive diaphoresis (NCLEX Question)

o Diuretics (high-ceiling)

o Wound drainage (especially GI)

o Decreased secretion of aldosterone

o Hyperlipidemia

o Kidney disease (scarred distal convoluted tube)

o NPO

o Low-salt diet

o Cerebral salt-wasting syndrome

o Hyperglycemia

● Relative Sodium Deficits (Dilution)

o Excessive ingestion of hypotonic fluids

o Psychogenic polydipsia

o Freshwater submersion accident

o Kidney failure (nephrotic syndrome)

o Irrigation with hypotonic fluids

o Syndrome of inappropriate antidiuretic hormone secretion

o Heart failure

● Treatment

o Decrease medication doses that increase Sodium loss (diuretics)

o IV saline infusion if occurring with a fluid volume deficit Severe cases require treatment with

3% or 5% saline (hypertonic solutions)

o If occurring with fluid excess, medications are given to promote water excretion and not

sodium excretion

o Nutritional therapy: increase oral sodium intake, decrease oral fluid intake

Hypokalemia causes:

● Actual Potassium Deficits

o Inappropriate or excessive use of drugs (diuretics, digitalis, corticosteroids)

o Increased secretion of aldosterone

o Cushing’s Syndrome

o Diarrhea

o Vomiting

o Wound drainage (especially GI)

o Prolonged NG suction

o Heat-induced excessive diaphoresis

o Kidney disease impairing reabsorption of Potassium

o NPO

Relative Potassium Deficits

o Alkalosis

o Hyperinsulinism

o Hyperalimentation

o TPN

o Water intoxication

o IV therapy with Potassium-poor solutions

▪ Treatment

● IV Potassium (NEVER given IV push, IM, SUB Q)

o Maximum concentration no greater than 1mEq/10 mL of solution)

● Oral Potassium supplements

o KCl causes vomiting and diarrhea, so give medication during or after a

meal (advise patients not to take it on an empty stomach)

● Avoid loop diuretics

o Switch to a Potassium sparing diuretic

● Nutritional therapy: eating foods high in Potassium, but taking supplement

until normal levels are maintained)

● Falls precaution

● Respiratory monitoring performed hourly (look out for increasing rate and

decreasing depth)

o Hyperkalemia: serum Potassium level higher than 5.0 mEq/L

▪ Causes

● Actual Potassium Excesses

o Over ingestion of Potassium-containing foods or medications (salt

substitutes, KCl, rapid infusion of Potassium-containing IV solution,

bolus IV Potassium injections)

o Transfusions of whole blood or packed cells

o Adrenal insufficiency

o Kidney failure

o Potassium-sparing diuretics

o ACE Inhibitors

● Relative Potassium Excesses

o Tissue damage

o Acidosis

o Hyperuricemia

o Uncontrolled Diabetes Mellitus

▪ Treatment

● Potassium restricted diet

● Potassium-excreting diuretics

● Kayexalate

● Dialysis (extreme cases)

● IV Insulin therapy (extreme cases)

o Hypercalcemia: serum Calcium levels higher than 10.5 mg/dL

▪ Causes

● Actual Calcium Excesses

o Excessive oral intake of Calcium

o Excessive oral intake of Vitamin D

o Kidney failure

o Use of thiazide diuretics

● Relative Calcium Excesses

o Hyperparathyroidism

o Malignancy

o Hyperthyroidism

o Immobility

o Use of glucocorticoids

o Dehydration

▪ Treatment

● Stop IV solutions containing Calcium (Ringer’s Lactate)

● Stop Calcium-based antacids

● IV normal saline because Sodium increases kidney excretion of Calcium

-Patient teaching for low-sodium diet, and good sources of potassium in the diet

● Low-Sodium Diet

o Focus on reducing sodium intake while remembering to stay hydrated

● Low-Potassium Diet

o Avoid eating: meats (especially organ meats and preserved meats), dairy products, dried fruit,

bananas, cantaloupe, kiwi, oranges, avocados, broccoli, dried beans or peas, lima beans, mushrooms,

potatoes, seaweed, soybeans, spinach

o Eat: eggs, bread, butter, cereals, sugar, apples, apricots, berries, cherries, cranberries, grapefruit,

peaches, pineapple, alfalfa sprouts, cabbage, carrots, cauliflower, celery, eggplant, green beans,

lettuce, onions, peas, peppers, squash

-Types of IV fluids: isotonic vs. hypo vs. hypertonic

▪ Isotonic

● D5W (dextrose 5% in H2O)

o Use for fluid loss, dehydration, hypernatremia

o Use cautiously in renal and cardiac patients

o Can cause fluid overload

● Normal saline (0.9% NaCl)

o Use for shock, hyponatremia, blood transfusions, resuscitations,

fluid challenges, DKA

o Can lead to fluid overload

o Use with caution in patients with heart failure or edema

● LR (Lactated Ringer’s)

o Use for dehydration, burns, lower GI fluid loss, acute blood

loss, hypovolemia due to third spacing

o Contains Potassium (no renal patients)

o Don’t use with liver disease patients or patients who cannot

metabolize lactate

▪ Hypotonic

● ½ Normal saline (0.45% NaCl)

o Use for water replacement, DKA, gastric fluid loss from NG tube or

vomiting

o May cause cardiovascular collapse or increased ICP

o Don’t use with liver disease, trauma, or burns

▪ Hypertonic

● Dextrose 5% in 0.45% NaCl

o Later in DKA treatment

o Use only when blood sugar falls below 250 mg/dL

● Dextrose 5% in 0.9% NaCl

o Temporary treatment for shock if plasma expanders are not available

o Addison’s crisis

o Don’t use in cardiac or renal patients

● Dextrose 10% in H2O