IV Fluids Flashcards
goals of fluid & electrolyte tx
maintain ECF in normal range, maintain isotonic state (BUN does NOT contribute to tonicity), maintain electrolytes and pH in safe range
principles of IVF usage
START and STOP dates, monitor and evaluate
who should receive especially stringent monitoring of IVF
elderly, diabetics, CHF
a U wave on ECG indicates..
hypokalemia
how do you evaluate hyponatremia?
- serum tonicity, 2. volume status, 3. urinary studies
what are the three places that potassium can go in hypokalemia?
cells, urine, stool (extrarenal, diarrhea!)
what test do you order to determine the cause of hypokalemia?
urine K+/Cr ratio (13=normal)
low K+/Cr ratio is consistent with?
redistribution, decreased intake, diarrhea, remote use of diuretics
what do you look at to determine the cause of low bicarb?
arterial blood gases and pH; anion gap
what are common causes of normal anion gap metabolic acidosis
diarrhea, RTA, kidney disease
D5W is?
isosmotic, but hypotonic (acts like water)
normal saline (NS) is?
isotonic; [Na+] = 154 or 0.9g% (9g/L)
be cautious with KCl because?
it is caustic to veins when given IV, must give at rate <40
lactated ringers may be better for?
circulatory shock
NaHCO3 may be used in cases of severe?
metabolic acidosis
3% hypertonic saline is?
hypertonic
who receives hypertonic saline?
SIADH, symptomatic hyponatremia
the purpose of normal saline is to?
expand the ECF volume; all NS distributes into ECF
what is the distribution of 1/2 NS?
1/3 into cells, 2/3 into ECF
what is the distribution of D5W (or water)?
2/3 into cells, 1/3 into ECF
what is the one scenario in which D5W is given to a patient with hypovolemia?
diabetes, because cells are shrunken (water goes into ECF but is lost by diuresis)
what is the 4 step assessment for writing IVF orders?
- ECF volume, 2. tonicity, 3. electrolytic abnormalities, 4. acid-base disturbance
IVF tx for diarrhea
normal saline + KCl for hypokalemia
which should be treated first: hypokalemia or hypobicarbonemia?
give K+ first, bicarb will worsen hypokalemia (think about maintenance phase of vomiting)
in a pt with hypovolemic hypertonic hypernatremia, what should be done?
- restore volume with NS, 2. restore water deficit
how to calculate water deficit
(0.5*weight in kg) x (measured Na/140 - 1)
if replenishing a water deficit, give it over ____ amount of time
24 hours
early goal directed tx in septic shock (SBP less than 90)
NS or lactated ringers (better than colloidal solutions) decreases mortality and risk of AKI
what is the best measure of cumulative fluid balance?
trends in weight (not central venous pressure)
fluid management in critically ill patients
- EGDT, 2. monitor weight, 2. AVOID FLUID OVERLOAD (goal pH 7.2)
name two mechanisms by which endurance exercise may result in hyponatremia
- pain induces SIADH, 2. increased water intake
tx of exercise-associated hyponatremia
3% (hypertonic) saline
tx of SIADH
3% saline (monitor every 1-2 hours)
what should not be given to a hypokalemic pt?
NaHCO3 or D5W (will worsen hypokalemia)
what should be avoided in pts with advanced kidney disease?
IV potassium
NS and LR are the fluids of choice for treating?
true hypovolemia (usually seen in setting of metabolic acidosis and hypokalemia - always tx hypokalemia first)
D5W is fluid of choice for?
hypernatremia IF no hyperglycemia or hypovolemia (if hypovolemic then NS first, then water replenishment)
1/2 NS is used for?
maintenance fluids, but monitor closely because 1/3 have SIADH and are prone to hyponatremia
IVF tx for DKA
insulin + NS
