A FEW THOUGHTS ABOUT FLUIDS IN KIDS

William Primack, MDUNC Kidney CenterChapel Hill NC USA

August 21, 2006

HOMEOSTASIS

The living organism does not really exist in the milieu exteriour (the atmosphere it breathes, salt or fresh water if that is its element) but in the liquid milieu interior formed by the circulating organic liquid which surrounds and bathes all the tissue elements, this is the lymph or plasma, the liquid part of the blood which in the higher animals is diffused through the tissues and forms the ensemble of the intercellular liquids which is the basis of all local nutrition and the common factor of all elementary exchanges.

The stability of the milieu interior is the primary condition for the freedom and independence of existence, the mechanism which allows of this is that which ensures in the milieu interior the maintenance of all the conditions necessary to the life of the elements.

Claude Bernard

Body spaces

Body spaces by age

Maintenance fluids

• Holliday M and Segar W– Pediatrics 1957;19:824

• 100 kcal~100ml• Their data led to the

100:50:20 protocol for the AVERAGE hospital patient

Maintenance fluids

• Holliday M and Segar W– Pediatrics 1957;19:824

• 100 kcal~100ml• Their data led to the

100:50:20 protocol for the AVERAGE hospital patient

• We never admit any kids like that!!!

MAINTENANCE FLUIDSWhat makes up 100 ml/kg

Water

(ml/100 kcal)

Respiratory 40-50

Sweat 0-5

Urine 50-75

Stool water 5-10

‘Hidden intake’ Water of oxidation

(10-15)

Totals 100-125

MAINTENANCE FLUIDSAbnormal lossesWater

(ml/100 kcal)

Abnormal losses

Range (ml/kg)

Respiratory 40-50 25-200

Sweat 0-5 0-25

urine 50-75 0-300

Stool water 5-10 0-100

‘Hidden intake’

Water of oxidation

(10-15)

Totals 100-125

Maintenance fluidsAdjustments to 100:50:20 rule

• Increase maintenance fluids– By 12 % for each degree C of fever– Insensible losses from 45 to 50-60 ml/100cal

for hyperventilation

• Decrease maintenance fluids– Insensible losses from 45 to 0-15 ml/100cal

for high humidity (= ventilator)

Maintenance fluids

• Unless you know what you are replacing and why, using maintenance plus (e.g. 1 ½ x maintenance) is illogical

Maintenance fluidsAn alternative approach

• Based on body surface area

• Use estimated insensible losses and replace all other fluid losses based on volume and content

• Recalculate as often as needed q6h-q24h

• Probably more accurate for PICU type patients

BODY SURFACE AREA

• BSA (M2) of average proportioned

•Newborn=0.25

•10 kg infant = 0.5

•30 kg child = 1.0

•70 kg adult = 1.73

•If average proportioned 3-30 kg

•BSA=(wt + 4)/30

MAINTENANCE FLUIDSDaily water requirement

Water

(ml/100 kcal)

Water looses per M2 BSA

Respiratory 40-50 400-600

Sweat 0-5 0-50

urine 50-75 750

Stool water 5-10 50-100

‘Hidden intake’

Water of oxidation

(10-15) (150)

Totals 100-125 1300-1500

Continuing losses

• NO MATTER WHICH SYSTEM YOU USE

• It is essential to regularly reassess child for continuing losses.

• Regularly reevaluate effectiveness of your fluid prescription and modify it p.r.n.

• May need to recheck labs more than q.d.

• Reweigh more than q.d. if appropriate

Contents of abnormal lossesmeq/liter

Fluid Na K Cl HCO3

gastric 20-80 5-20 100-150 0

pancreatic 120-140 5-15 40-80 40-60

small bowel 100-140 5-15 90-130 25-40

bile 120-140 5-15 80-120 20-40

ileostomy 45-135 3-15 20-115 20-50

diarrhea 10-90 10-80 10-110 5-35

Comparison of Electrolyte Composition of Diarrhea Caused by Different Organisms

EtiologyElectrolytes

(mMol/L)mOsmols

Na+ K+ Cl HCo3

Cholera 88 30 86 32 300

Rotavirus 37 38 22 6 300

ETEC 53 37 24 18 300

Molla et al. J Pediatr 1981; 98: 835

MAINTENANCE FLUIDSFluids based on BSAWater

(ml/100 kcal)

Water

(ml/M2)

Na

MEQ/M2

K

MEQ/M2

Insensible

loss

45 400-600 0 0

Sweat 0-25 0-200 20 20

urine 50-75 750 0-200 5-100

Stool water 5-10 100 30 30

‘Hidden intake’

(10-15) (150) 0 0

Totals 100-125 1300-1500 50-250 55-155

Case 1

• 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 24 hours

• On exam decreased turgor, dry mouth, BP 90/60, wt= 9 kg.

• Labs Na=140, K=4, HCO3=17, BUN=30, creatinine=0.4.

• Receives 10-20 ml/kg bolus and makes some urine

Isotonic dehydration

Isotonic dehydrationcorrection

water Na K HCO3

maint 1000 25 20 0

deficit

Isotonic dehydrationcorrection

water Na K HCO3

maint 1000 25 20 0

deficit 1000 75 75 20

total 2000 100 95 20

½ in first 8 hrs, remainder over 16 hours

Reassess for and replace continuing losses

Case 2

• 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 24 hours

• Given ‘clear fluids’.• On exam decreased turgor, dry mouth, BP

80/50, wt= 9 kg.• Labs Na=125, K=4, HCO3=15, BUN=40,

creatinine=0.4.• Receives 10-20 ml/kg bolus and makes

some urine

Hypotonic dehydration

Hypotonic dehydrationcorrection

water Na K HCO3

maint 1000 25 20 0

deficit 1000 75 +

Hypotonic dehydrationcorrection

(Desired Na – measured Na) X TBW

(135 – 125) meq/l X .6 l/kg = 6 meq/kg

Thus deficit= 60 meq Na

Hypotonic dehydrationcorrection

water Na K HCO3

maint 1000 25 20 0

deficit 1000 75 + 60 75 30

total 2000 135 95 30

½ in first 8 hrs, remainder over 16 hoursReassess for and replace continuing losses

Case 3

• 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 48 hours

• Continues to drink cow’s milk• On exam nl to ‘woody’ turgor, moist

mouth, BP 90/50, wt= 9 kg.• Labs Na=170, K=4, HCO3=18, BUN=25,

creatinine=0.4.• Receives 10-20 ml/kg bolus and makes

some urine

Hypertonic dehydration

Hypertonic dehydrationcorrection

water Na K HCO3

maint 750 25 20 0

deficit 1000

total

Lower maintenance water requirement as high ADH will decrease UO

Hypertonic dehydration initial day correction

water Na K HCO3

maint 750 25 20 0

deficit 1000 75-65=10 25 20

total 1750 35 45

Target is to drop Na by 10 meq/day.Lower maintenance requirement as high ADH will decrease UOReassess for and replace continuing losses

Hypertonic dehydrationcorrection

• Lower maintanence requirment as high ADH will decease UO

• Goal is to decrese Na by 10 meq/day

(Desired Na – measured Na) X TBW

(165 – 175) meq/l X .6 l/kg = 6 meq/kg

Thus sodium surplus= 60 meq Na

Comparison of Effect of Glucose on Net Stool Rate with Galactose and Fructose in Perfusions Delivered Uniformly throughout Most of the Small Intestine via Multilumen Tube

12-HOUR PERIODS

Pre-perfusion

Perfusion with electrolytes and 61 mM galactosePerfusion with electrolytes and 56 mM fructosePerfusion with electrolytes and 58 mM glucosePerfusion with electrolytes only

Post-perfusion

600

500

400

300

200

100

1 2 3 4 5 6 7 8 9

ME

AN

NE

T S

TO

OL

OU

TP

UT

RA

TE

(m

l/h

r)

Adapted from Hirschhorn N et al. N Engl J Med 1968; 176

Na-glucose co-transport Intestinal brush border

Duggan C JAMA 2004;291:2628

Outcome of Oral Treatment of 216 Patients with Rotavirus

Initial Treatment Success Failure*

Oral (n = 197) 188 (95) 9 (5)

Intravenous (n = 19) 17 (89) 2 (11)

Total (n = 206) 205 (95) 11 (5)

*Requiring unscheduled treatment intravenously.Percentages are given in parentheses.

Taylor PR et al. Arch Dis Child 1980; 55(5):376-379

Spandorfer et al.Pediatrics 115 (2): 295. (2005)

ORAL vs IV REHYDRATION IN MODERATE DEHYDRATION

ORS

• 30-50 ml/kg over 3-4 hours of ORS

• If vomiting give in sips (Pedialyte pops)

• May also add 5-10 ml/kg per diarrheal stool for ongoing losses

• Expect increased stool content

• After rehydration, CHO rich foods

• Continue nursing

ORS and other ‘clear liquids’

CHO

g/l

Na

Meq/l

K

Meq/l

Cl

Meq/l

base

Meq/l

mOsm/kgH20

Pedialyte 2.5 45 20 35 30 250

WHO ORS 2.0 75 20 65 30 280

Gatorade 5.9 21 2.5 17 0 377

Apple juice 11.9 0.4 26 -- -- 700

Coca cola 10.9 4.3 0.1 -- 13.4 656

OJ 10.4 0.2 49 -- 50 654