IV fluids Flashcards
where is body water
1/3 ECF
2/3 ICF
where is water in ECF
1/4 plasma (8% total)
3/4 ISF (25% total)
how much fluid and lytes are needed per day
4-2-1 rule
4 ml/kg/h for 1st 10kg
2 for next 10
1 for rest
def. effective osmole
particle that doesn’t cross cell membrane
- Na, K, glucose
- NOT ethanol and urea
what are 2 types of losses
sensible - those you feel - urine
insensible - those you don’t - sweat, resp
what is “free water” in 1 L of 70mmol/L fluid
500 ml is isotonic (140)
so 500ml is free
4 types of fluid loss
- pure water loss
- hypotonic
- isotonic
- blood
2 ways to lose free water
- . skin - insensible
- urine
- diabetes insipidus
- urea induced osmotic diuresis
3 ways to lose hypotonic
- skin
- sweat (20-50 Na) - urine
- most diuretics
- glucose or mannitol induced - GI
- vomiit
- diarrhea if due to osmotic laxative
4 ways to lose isotonic
- skin
- burns - GI
- most diarrhea
- ileus - urine
- thazides - third space losses
3 consequences of fluid loss
- hypovolemia
- less CO > hypotens> activate SNS - possible hypernatremia
- brain cells shrink> confusion - possibly lose other lytes
magnitude of blood volume lost for a liter loss of each type
- pure water loss - 80ml
- hypotonic - 80-250
- isotonic - 250-333
- blood- 1000ml
3 hormonal responses to hypovolemia
- SNS activation
- RAS activations
- ADH
effects of hormones (3)
- incr. CO
- vasoconstrict
- reduce urine loss and NaCl
4 Hx ways to assess loss
- urine (output, color)
- thirst/intake
- dizzy when standing
- direct evidence of loss
- blood, surg, GI etc
4 hemodynamic signs on Phx
- JVP
- postural hypotension
- postural rise in HR
- supine hypotens or BP
5 other signs of low volume
- skin and mucous
- tugor
- cap refill - urine
- weight loss
- CNS
- confusion/coma - head
- fonanelle
- sunken eyeballs
what are three general levels of loss in adults1
mild - 1-2 liters
mod - 2-3
severe - 4-5
fomula for free water deficit
[total body water x (plasma [Na] - 140)]/140
how much water in man and woman
man 60%
woman 50%
4 lab tests to help confirm hypovolemia
- urine
- osmolarity rises - test specific gravity - ratio of plasma urea:creatinine
- rises to >8%
- urea rises faster since reabsorbed with Na - hematocrit/hemoglobin
- compare to previous levels - check for other lyte abnormalities
3 indications of IV fluids
- existing large deficit
- anticipated large def.
- access to circulation for meds
what are crystalloids and colloids
crystalloids - Saline/dextrose
colloids
- large mol. weight substances
what happens when give saline
- all stays in ECF
- no change in [Na]
what happens when give dextrose
water goes 2/3 ICF, 1/3 ECF
[Na] down
what happens when give half normal saline
half is like normal, half is like dextrose
what is formula for change in plasma [Na] for giving a liter of fluid
(IV[Na] - patient [Na])/ (total body water +1)
3 types of colloids
- abumin (5 and 25%)
- starch solutions
- fresh frozen plasma
why give colloid
expect to stay in intravascular better
4 steps to give fluids
- estimate and replace existing deficit
- replace ongoing def.
- reassess respnse to ther
- decide if additional are needed
what to give if hypernatremic
- may need free water
- may also need isotonic
- not too fast
what to give if hyponatremic
- avoid free water
** mega important point about hypotonic fluids
don’t give to sick patients unless they are hypernatremic
- sick patients make ADH so don’t excrete free water
4 possible routes
- periph vein IV
- central line
- intraosseous in kids
- continuous sub cut
check cases
it’s shreiber
