Fluid Management

Question 1

3 overall goals of fluid management

Answer 1

1. maintain ECF
2. maintain isotonicity
3. maintain electrolytes and pH

Question 2

important things to remember w/ IVFs

Answer 2

they are drugs! need start and stop dates, evaluations for success/failure, monitoring

Question 3

D5W

Answer 3

dextrose 5 water- dextrose taken into cells quickly, essentially giving free water

isosmotic but hypotonic- used w/ hypernatremia w/ volume status is not as big an issue

Question 4

NS 0.9% saline

Answer 4

isotonic- helps to rapidly expand ECF when volume depleted

Question 5

1/2 NS

Answer 5

hypotonic but more than D5W, used as maintenance fluid

not as helpful w/ SIADH

Question 6

KCl

Answer 6

help to replenish K stores, give w/ NS if hypovolemic and hypokalemic

less than 40 mEq/h iv

Question 7

lactated ringers

Answer 7

has some Na, K, lactate but is isotonic (similar use as NS)

dont give w/ liver failure (cant break down lactate) or alkalosis (lactate broken down into bicarb)

Question 8

3% hypertonic saline

Answer 8

given w/ symptomatic hyponatremia (neuro sx usually) esp w/ SIADH

Question 9

NaHCO3 sln

Answer 9

can be D5W w/ 50, 100, 150 mEq of NaHCO3

only used when pH very low, only need to correct to 7.2

Question 10

describe distribution of NS

Answer 10

stays in ECF- isotonic so no osmotic force to pull into cell

Question 11

distribution of 1/2 NS

Answer 11

half of the fluid will stay in ECF

other half: 2/3 in ICF, 1/3 in ECF

Question 12

D5W distribution

Answer 12

2/3 in ICF, 1/3 in ECF

1/3 usually not enough to help bring up volume status, need to be careful when adding so much volume to ICF

Question 13

4 things to assess when ordering IVF

Answer 13

1. volume
2. tonicity
3. electrolyte abnormality
4. acid base

Question 14

how to calculate water deficit (w/ hypernatremia)

Answer 14

water deficit= (weightx%water) x(Na concentration/140 -1)

this needs to be corrected over a span of 24 hrs

Question 15

why not use albumin?

Answer 15

expensive, never use w/ head trauma

use if unresponsive to crystalloids

Question 16

benefit of LR

Answer 16

balanced (has some base), lower AKI risk

Question 17

fluid considerations w/ acute lung injury

Answer 17

+ fluid balance has higher mortality, be more conservative w/ giving fluids

higher diuretics have protective effect w/ both acute kidney and lung injury

Question 18

measure of cumulative fluid balance

Answer 18

body weight is best measure

Question 19

describe excercise induced hyponatremia

Answer 19

SIADH can occur from exercise, pain

increased free water intake causes hyponatremia- not enough to improve ECF and can cause cerebral edema

weight gain w/ SIADH is bad prognostic factor

Question 20

tx priorities w/ hypokalemia

Answer 20

tx w/ KCl before correcting acidosis or adding D5, dont want to make hypoK worse

Question 21

when to avoid K fluids

Answer 21

advanced kidney disease

Question 22

when to avoid treating met acidosis

Answer 22

dont overtreat w/ critically ill pts, goal is to get up to 7.2

Question 23

which settings of hypernatremia would you not use D5W

Answer 23

hypovolemia (need to correct this first)

hyperglycemia (insulin first to correct this osm and osmotic diuresis problem)

Question 24

tx w/ DKA

Answer 24

insulin and NS should correct acidosis