Regulating Fluids
The thirst mechanism, the primary regulator for fluid intake is located here (Pearson 361)
What is the hypothalamus?
A number of stimuli trigger this center, including osmotic pressure of body fluids, vascular volume, and angiotensin (hormone released in response to decreased, flood flow to the kidneys)
Normal serum sodium level (pearson 363)
(135-145 mEq/L)
Sodium is the most abundant fluid in ECF and a major contributor to serum osmolality
2 Risk factors for hypernatremia (ATI 284-285)
Kidney failure, Cushing's syndrome, aldosteronism, some medications, excessive oral sodium intake, NPO status, hypertonic, enteral feedings without adequate water supply, diabetes insipidus, heatstroke, hyperventilation, watery stools, burns, excessive sweating
Potassium rich foods (include 3) (f&e powerpoint class activity)
Dried fruits (raisins, apricots)
Beans, lentils.
Potatoes,
Winter squash (acorn, butternut)
Spinach, broccoli.
Beet greens.
Avocado.
Bananas
Sodium polystyrene sulfonate
Average oral intake for an adult. (Pearson 361)
What is 1200-1500 mL?
Water from foods makes up about 450 mL
Water as a byproduct from food metabolism makes up about 200 mL
Major functions of sodium in the body (pearson 364)
Regulates ECF volume and distributuon
Maintaining blood volume
Transmitting nerve impulses and contracting muscles
Expected findings of hypernatremia (ATI 285)
Thirst, hyperthermia, tachycardia, orthostatic hypotension, restlessness, irritability, muscle twitching/weakness including respiratory compromise, seizure, coma
DOUBLE JEOPARDY
Major functions of K+ in the body (name one) (Pearson 364 and 393)
Maintain ICF osmolality
transmitting nerve and other electrical impulses
regulating cardiac impulse transmission
skeletal and smooth muscle function
regulating acid-base balance
(Both hyperkalemia and hypokalemia can lead to deadly cardiac dysrhythmias and ECGs are a diagnostic test for both)
Which loop-diuretic would the nurse anticipate prescribed in and pt with high potassium levels? (ATI 288)
Furosemide
Average daily urine output (Pearson 362)
1400-1500 mL/24 hr or 0.5 mL/kg per hour
Insensible loss through lungs: 300-400 mL skin: 300-400 mL
Sweat: 100 mL
Feces: 100-200 mL
Sodium containg foods (f&e in class pp activity)
Canned soup, processed cheeses and meats, broth, salted butter savory snacks
increased blood sodium, blood osmolarity, and urine specific gravity
Expected serum potassium levels (pearson 365)
3.5-5.3 mEq/L
(3.5-5 mEq/L in the F&E in class pp activity)
Which potassium-sparring diuretic would the nurse anticipate for a pt. with low potassium?
spironolactone
This hormone, synthesized by the anterior hypothalamus, acts of the collecting ducts of the nephrons, regulating water excretion by the kidneys (Pearson 363).
ADH- antidiuretic hormone
When Serum osmolality rises, ADH is produced, causing the collecting ducts to become more permeable to water. This allows more water to be reabsorbed into the blood.
Can also be affected by blood volume, temperature, pain, stress, and some drugs
3 expected findings of hyponatremia (ATI 284)
vitals hyponatremia in a hypervolemic- bounding pulse and hypertension
hypovolemic vitals include- hypothermia, tachycardia, rapid thready pulse, hypotension, diminishes peripheral pulses
neuromuscular: headache, confusion, lethargy, muscle weakness with potential respiratory compromise, fatigue, decreased deep tendon reflexes, seizures, lightheaded/dizziness
GI: increased motility, hyperactive bowel sounds, abdominal cramping, nausea
other: Dry membranes, increase urinary output
2 nursing interventions (ATI 285)
Administer medications as prescribed, seizure precautions, monitor vitals, monitor I&O's, monitor labs, monitor for swelling/edema, administer IV fluids as prescribed and encourage water intake
Expected findings of hyperkalemia (ATI 287 and pearson 393)
blood potassium level greater than 5.0 mEq/L
slow irregular pulse, hypotension, diarrhea, hyperactive bowel sounds, nausea/vomiting, abdominal pain
restlessness, irritability, muscle twitches, profound weakness, paresthesia
tall, peaked T waves and widened QRS, premature ventricular contractions, ventricular fibrillation
Expected findings of hypokalemia (ATI 286)
Flattened T waves, prominent U waves, ST depression, prolonged PR interval, hypoactive bowels sound, nausea, vomiting, constipation, abdominal distention, weakness, reduced deep tendon reflexes, shallow respirations
This system restores blood volume and renal perfusion through sodium and water retention in response to release of renin (Pearson 363)
renin-angiotension-aldosterone system
Name 3 etiologies of hyponatremia (Pearson 393)
diuretic use, renal disease, adrenal insufficiency, vomiting, diarrhea, excessive GI suctioning, repeated tap-water enemas, burns, heart failure, and administration of IV hypotonic fluid
A nurse is caring for a pt. with heart failure who is prescribed high does of diuretic. Nurse notes flat neck veins, generalized muscle weakness, a diminished deep tendon reflexes. The nurse suspects hyponatremia, what additional signs would the nurse expect? 1. Muscle twitches 2. Decreased urinary output 3. Hyperactive bowel sounds 4. Increased specific urine gravity
Causes of hyperkalemia (Saunders 100, ATI 287, Pearson 393)
Potassium-sparring diuretic use, excessive potassium intake, adrenal insufficiency, acidosis, severe tissue trauma, starvation (Pearson).
older adults due to decrease in renin and aldosterone, increased use of salt substitutes, ace inhibitors, and potassium-sparing diuretics, excessive oral intake or IV replacement, Kidney failure, extracellular shift caused from decreased insulin production, hyperuricemia (ATI)
(Saunders includes most things listed above with addition of Addison's disease)
Why is IV potassium supplementation highly cautioned? (ATI 286)
It can cause cardiac arrest and should never be given by direct IV bolus (usually administered IVPB)