Medical Knoweledge Flashcards
largest water space in body?
smallest?
intracellular 40%
intravascular
What recylces interstiital cluid and where does it end up?
lymph, vasc
intra v extra predom K vs alb
K intra
alb extra
intracellular cations and anions
extra?
K and mg; protein and phos
na; Cl and bicarb
intavascular overall cation concentration is higher due to
high protein anions
blood transfusion effect on intravasc osm pressure
decrease as water is pushed out by large particle
4-2-1 rule?
1ml/kg first 20 K
2 10K
4 10K
components of NS and LR
definition of oliguria in 70 kg man
Oliguria in a 70-kg man is defined by less than 400 mL of urine produced and excreted in a 24-hour period.
For icu patients what would we prefer hyper vol or hypo and why?
hyper
pulm failure carries 25% mortality while kidney failure 48%
signs of high IV fluid status
High output generally will mean that the body is trying to rid itself of water; surgeons should assist it by decreasing the maintenance fluid rate. Anasarca is another helpful clue, as are the customary vital signs.
How does Pto F ratio help with determining fluid status
poor ratio equals fluid in inteerstitium
usual reason for post op low uopin surg patients
In most, if not all such patients, low urine output postoperatively means that they have deceased renal blood flow from insufficient intravascular volume.
stress dose regimen for adrenal insufficiency
50 mg hydrocortisone q8h
severe hyponatremia s/s
mech
Severe hyponatremia, however, can cause headaches and lethargy; patients can even become comatose or have seizures.
brain cell swelling
3 broad causes of hyponetremia
iatrogenic
brain
lung
bodys normal initial response to hyponatremia?
What volume status is this hindered by
adh suppression
hypovol state causes pituitary to secrete adh
adh secreting tumors
small cell lung and carcinoid
the 3 volume states of hypernatremia and teh causes
Hypovolemic hypernatremia commonly occurs in dehydrated patients with low water intake, high fluid losses such as vomiting, nasogastric tube loss, or diarrhea. Euvolemic hypernatremia is seen in patients with DI (nephrogenic or neurogenic) because of excess loss of urinary free water. Hypervolemic hypernatremia is usually iatrogenic caused by resuscitation with hypertonic solutions or a result of excess mineralocorticoids in Conn or Cushing syndrome.
what controls potassium excretion
RAAS aldosterone
consequences at differing levels of hypokalemia
ve a [K+] lower than 3.5 mmol/L. Hypokalemia is commonly a result of hyperpolarization of the resting potential of the cell. Hyperpolarization interferes with neuromuscular function. Hypokalemia is associated with generalized fatigue and weakness, ileus, atrial arrhythmia, and acute renal insufficiency. On occasion, rhabdomyolysis occurs in patients whose [K+] drops below 2.5 mmol/L. Flaccid paralysis with respiratory compromise can occur as [K+] decreases to less than 2 mmol/L.
2 electrolyte associations with hypok
hypo mg and acidemia
ekg changes with hypo K
arrythmias?
depressed T and U waves
atrial tach, v tach, v fib
why is hypokalemia so stubborn
severe intracellular depletion is needed to show up in serum