Fluid and Electrolyte Replacement Flashcards
CM in volume depletion with 5% loss
thirst, dry mucous membranes
CM in volume depletion with 10% loss
tachycardia, oliguria
CM in volume depletion with 15-20% loss
hypotension, tachycardia, narrow pulse pressure
what is most sensitive indicator for volume loss?
heart rate- tachycardia
patient that is hypernatremic. You give fluids to get sodium level down. What is a good guideline for changing sodium levels?
do not change sodium levels more than 12 mOsm/24 hours
Types of volume depletion
water deficit with or without solute deficit
water deficit without solute deficit. Tx for calculating change in total body sodium
change in sodium = (140 - Patient’s Na level) X TBW (or wt. in kg x 0.6)
what fluid to use in hypernatremic patient that is stable and non-hypotensive?
D5W
what fluid to use in hypernatremic patient that is hypotensive?
use hypotonic soln (but will require more of it)
Tx in patient in hypovolemic shock
20 ml/kg bolus NS, then repeat bolus of 10-20 ml/kg until systolic pressure above 80 mmHg
Tx in patient with volume depletion from diuretic loss. Not in hypovolemic shock.
1 L NS over first hour, then 500-1000 ml NS second hour OR 10 ml/kg for every 1% dehydration. half given over 8 hours, remaining half given over 16 hours
Tx mild volume overload
Na restriction to less than 2 g Na/day (CHF patients)
tx severe volume overload
diuretic (lasix)
Hyponatremia tx if sodium more than 125 mEq/L
water restrict
Hyponatremia tx if sodium less than 125 mEq/L
Diuretics
In hyponatremia, should you correct all of the sodium deficit?
No, only half because also water restriting, using diuretics
equation for calcuting sodium deficit in hyponatremia
Na deficit per L= desired sodium - patients sodium. Total sodium deficit is that value x TBW
at what rate do you correct sodium deficit?
replace at 0.5 mEq/hr
how much sodium in 1.8% Nacl?
300 meq/l
how much sodium in 3% nacl?
513 meq/L
effect of potassium in acidic environment?
H ions will go into cells, and potassium will get kicked out, resulting in INCREASED levels- inc excitability of cells
EKG in hypokalemia
prolonged PR interval, new wave after T
EKG in hyperkalemia
prolonged PR interval, widened QRS, tall peaked T waves, sine waves
most feared consequence of hyperkalemia
life threatning arrhythmias- PEA, asystole
fake causes of hyperkalemia
Hemolysis, potassium infusion, check CBC- infection causing shifting of ions out of the cell
EMERGENCY Rx Hyperkalemia
1-2, 10 ml ampules of 10% calcium gluconate over 2-5 minutes. also, Give 10U Regular Insulin IV push with 1 ampule D50 IV push. can also give albuterol, sodium bicarbonate, lasix (caution)
Non emergent Tx hyperkalemia (if have more time to correct)
Kayexelate 30-60 gm PO (sodium polystyrene sulfonate)
dangerous consequences of hypokalemia
arrhythmia, paralysis, rhabdomyolysis
refeeding syndrome can result in what electrolyte abnormalities?
hypokalemia, hypophasphatemia, hypomagnesemia, and sometiems hypoglycemia
refeeding syndrome triggered by
intense insulin secretion
estimating K deficit
For every 100 mEq below normal, serum K drops by 0.3 mEq/L. Or for every 10 mEq below normal, serum K drops by 0.1 mEq
after calculating K deficit in hypokalemia, what route do you choose to replace?
ORAL preferred- quicker, less SE, less dangerous
In what situations do you choose IV K replacement in hypokalemic patients?
If NPO or have severe depletion, K at 2.7 or less. complete heart block
preferred agent in hypokalemia replacement
KCL oral 60-80 meq
replacing K in DKA patients
potassium phosphate
replacing K in metabolic acidosis
potassium acetate, bicarbonate, citrate, or gluconate
You decide to use IV KCL to restore potassium in your severely volume depleted patient. You do a “Piggyback” with 40-60 mEq K. What solution do you AVOID?
dextrose- triggers insulin, which causes K into cells. Use NS
Lidocaine IV- caution
can cause arrhythmias so caution
Lidocaine IV benefit
prevents phlebitis
Severe hypokalemia patient. You decide to use combination of oral and IV. What doses/rates are used?
KCl PO 60-80 mEq BID or TID. KCl IV 10 mEq/hr
gentle vs. aggressive tx in hypokalemic patients
DKA and IV diuretic patients- AGGRESSIVE. keep K above 4-4.5 in cardiac patients. Gentle in acute or chronic renal failure patients
always check this electrolyte in cases of refractory hypokalemia
MAGNESIUM!
Acidosis effect on calcium
increases free calcium
alkalosis effect on calcium
more bound calcium (decreaesd free calcium). proteins give off H ions and bind calcium
tx in hypocalcemia is only indicated in symptomatic patients. IV avoided.
1-3 grams of Calcium chloride depending on serum ionized calcium level
tx in symptomatic patient (fatigue, weakness, kidney stones) with serum calcium level of 13 mg/dL
Hypercalcemia- NS 300-500 ml/hour, tapering to 200-250 ml/hr
Hypercalcemic patient with level greater than 16 mg/dL tx:
NS load, calcitonin to promote osteoblasts to build bone, and bisphosphonates to prevent breakdown of bone
Chvostek’s sign, Trousseau’s sign think
hypocalcemia
Claudin-19
tight junction protein that allows for Mg and Ca reabsorption in kidney
Mg is reabsorbed in ..
thick ascending loop of henle by passive diffusion based on sodium reabsorption. claudin-16 also plays a role in its reabsoption
What 3 factors decrease Mg reabsorption
Increased plasma calcium, decreased pH, and low potassium
food sources magnesium
green vegetables, legumes( beans and peas), nuts and seeds, unrefined grains, tap water
