fluid, electrolytes, acid-base Flashcards
Total body water accounts for ____% body wt?
60%
Of the total body water, how much is located intracellularly? Extracellularly?
2/3 and 1/3 (#mental math)
Extracellular fluid is composed of _________ and __________________
plasma, interstitial fluid
What is a normal fluid intake/day
1500mL
What is a normal urine output/day
800-1500mL
there are 4 types of fluid replacement. What 2 increase intravascular fluid? What 2 increase intercellular fluid?
Intravascular: NS and Lactated Ringer’s
Intracellular: D51/2NS and D5W
Loss of fluid through sweat and respiration is called?
Insensible loss
What do labs look like in a dehydrate patient?
high serum Na with BUN/Cr ration >20:1 (hypoperfusion of kidneys) high hct, high osmolarity of blood
What is the goal urine output for an adult? Child?
Adult: 0.5 mL/kg/hr
Child: 1mL/kg/hr
When giving bolus fluids, should you include dextrose or potassium?
No, this can lead to hyperglycemia or hyperkalemia (Lactated Ringer’s). Give NS bolus and do mixture for maintenance dose
How do you calculate maintenance fluids?
Give 4mL/kg for first 10kg, 2mL/kg for next 10kg, and then 1 mL/kg for remainder of weight per hour.
4/2/1 Rule
Ex: 70kg man. 4mL x 10kg + 2mL x 10kg + 1mL x 50kg = 110mL/hour
If you increase Na, where do you see an increase in fluid volume?
Extracellular fluid
High Na = increased/decreased GFR?
increased
Hyponatremia is caused by too much _________ and hypovolemia is caused by too little __________
water, sodium
What is the major concern for hypernatremia?
osmotic effects on the brain, water leaves brain cells leaving them dehydrated
What factors are involved in balancing calcium?
PTH, calcitonin, vit D, albumin, pH
What is the normal Ca+ range?
8.5-10.5mg/dL
calcium exists in what 2 forms?
Protein bound (albumin controlled) and Free ionized (PTH controlled)
Increased/decreased pH increases the binding of Ca to albumin?
Increased
What organs are involved in calcium regulation?
Bone (breakdown, remodeling)
Kidney (Ca reabsoprtion vs phosphate reabsorption)
Gut (activation of vit D)
Low calcium results in __________ deep tendon reflexes?
Hyperactive (chvostek and trousseau signs)
HYPERcalcemia will __________QT interval and
HYPOcalcemia will _____________QT interval.
hyper = shorten hypo = lengthen
Too much calcium results in what generic nmeumonic?
stones, bones, groans, moans
What is the normal K+ range?
3.5 - 5.0
T/F. Potassium level is greatly affected by pH
true
alkalosis moves K into cells.
acidosis moves K out of cells
What are some causes of potassium loss?
GI, Renal, insufficient diet, sweating, bactrim
How do you treat low K? how important is it?
KCl, treat right away to avoid cardiac arrhythmia
How do you treat high K?
IV Ca to stabilize membrane potential (immediately)
What electrolyte imbalance is the most dangerous and rapidly fatal?
hyperkalemia
What are normal Mg levels?
1.8-2.5mg/dL
Where is most of the body’s Mg?
bones
What other electrolytes are related to Mg levels?
hypomagnesemia makes hypokalemia and hypocalcemia more difficult to tx
What complications occur with too much Mg?
arrhythmia, coma, resp failure
How do you treat too much Mg?
IV Ca to stabilize heart, intubate, saline+loop
What are normal phosphate levels?
3-4.5mg/dL
Where is your P stored?
bones
What are the 2 most common causes of low phosphate?
ETOH and DKA
