a few thoughts about fluids in kids william primack, md unc kidney center chapel hill nc usa august...
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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
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 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 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 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
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
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