FLUID MANAGEMENT IN THE PAEDIATRIC PATIENT

Dr Riyas A

Water physiology

Water is the most plentiful constituent of the human body

approximately 75% of birthweight for a term infant

decreases to approximately 60% of body weight during the 1st yr of life and basically remains at this level until puberty

Fluid Compartments

TBW is divided between 2 main compartments intracellular fluid (ICF) extracellular fluid (ECF)

ECF Plasma Interstitial fluid Transcellular fluid

Fluid compartments & volumes changes with ageComponents

Premature

Neonate

Infant Adult

ECF 50 35 30 20

ICF 30 40 40 40

Plasma

5 5 5 5

Total 85 80 75 65

Transcellular fluid

CSF Synovial fluid Digestive juices Intraocular Pleural Pericardial peritonial

Continu….

Plasma water is 5% of body weight

Blood volume is usually 8% of body weight

The volume of plasma water can be altered by pathologic conditions dehydration, anemia, polycythemia, heart

failure, abnormal plasma osmolality and hypoalbuminemia

Continu…

Interstitial fluid - normally 15% of body weight

can increase dramatically in diseases associated with edema heart failure, protein-losing enteropathy,

liver failure, nephrotic syndrome, and sepsis

Electrolytes

Exist as ions Cations – positively charged Anions – negatively cahrged

Concentrations expressed as meq/L

Electrolyte Content of Body Fluids

Electrolyte Composition in Body Fluids (Normal)  Electrolyte

Plasma Exracellular

Intra cellular

Na+ 142 145 10

K+ 4 4 159

Mg2+ 2 2 40

Ca2+ 5 3 1

Cl- 103 117 10HCO3

- 25 27 7

Daily Loss of Water

Source of Loss

Normal Activity and Temperature (mL)

Normal Activity High Temperature (mL)

Prolonged Exercise (mL)

Urine 1400 1200 500

Sweat 100 1400 5000

Feces 100 100 100

Insensible losses

700 600 1000

Total 2300 3300 6600

Determining fluid requirement Howland ----1911----energy

consumption in children In 1957 holliday and segar

correlated calorie requirement with basal metabolism and active energy needs

Calorie requirement is

0-10kg=100kcal/kg/day 10-20kg=50kcal/kg/day+1000kcal

>20kg=1500kcal+20cal/kg Mb of 1cal produces 0.2ml of water

and consumes 1.2ml On transporting this in to hourly

basis

Continu…

0-10kg4ml/kg/hr 10-20kg40ml+2ml/kg/hr >20kg60ml+1ml/kg/hr Fever increses the calorie

requirement by 10-20%for every centigrade rise

Clinical assessment of dehydartion

Symptoms&signs

Mild Mode Severe

Wt loss <5 5-10 >10

General condition

Alert/restless Thirsty/lethrgic

Cold/thirsty

Pulse Normal rate /voume

Rapid/weak Rapid/feeble

Respiration Normal Rapid Rapid/deep

Systolic pressure

N N/Low Unrecordable

Anterior fonta N/sunken Sunken Very sunken

Eyes n/sunken Sunken/dry Grossly sunken

Skin N Decreased Markedly decresed

Mucous membrane

Moist Dry Very dry

Urine output Adequate Less ,dark coloured

Oliguria/anuria

Capillary filling Normal <2sec >3sec

Estimated deficit

30-50ml/kg 60-90ml/kg 100ml

Investigation for confirming dehydration Serum osmolarity /serum sodium Acid base status,serum ph and base

deficit Serum potassium compared with ph Urine output

Correction of flui deficit Done in three phases Emergency phase20-30ml/kg over

10-20min (intital resucitation with isotonic saline

Repletion phase 125-50ml/kg over 6-8hr(or half the deficit)

Repletion phase 2remainder of the deficit

Mild dehydration

Correction is with ORS Package containing Glucose 20gm/Lwater Nacl 3.5gm/Lwater Kcl4.5gm/Lwater Trisodium citrate 2.9gm/Lwater Sodium bocarbonate2.5gm/L water

Compensatory mechanism

Definite temporary

Nil per oral guidlines

Age Milk and fat free solids

Fluids

<6mnths 3-4hr (breast milk)

2hrs

6-36mnths 6hrs(formula breast feeds)

3hrs

>36mnths 8hrs fatty feeds or solids

3hrs

Body requires

Maintenance fluid Replacement fluid Maintenance fluid hypotonic fluid 4 basic reason 1)evaporation 2)excretion through kidney and

stools 3)through respiratory tract 4)growth

Fluid required to compensate for fasting The younger child with higher basl

metabolism Prolonged fsting which occurred

inadverently or out of necesssity In the hot summer m0nth A febrile child In polycythemia when there is a risk

of dehydration predisposing to thrombosis

Monitoring fluid loss an replacement Routine monitoring pulse

oxy,nibp,ecg,precordial stethescope 15-20%

Urine out put

Selection of fluid

Depend on condition of patient Surgery hct

Intra operative fluid replacementSurgical trauma

Type of surgery

Fluid replacement

Minimal Inguinal repair

1-2ml/kg/hr

Moderate Ureter reimplantation

4ml/kg/hr

Severe Scoliosis,intra abdominal surgery

>6-8ml/kg/hr

heamatocrit

A normal hct means ,a hct within two standard deviation for the age

An acceptable hct is with which an infant or child can tolerate with out blood transfusion

Blood

The use of blood products in pediatric surgical patients has diminished greatly because of the fear of transmission of disease—particularly human immunodeficiency virus (HIV). Because HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), and a number of other disease-causing viruses can be transmitted with as little as 10 mL of packed red blood cells (PRBCs), administration of any blood product requires clear, medically defensible clinical indications that are preferably recorded on the anesthetic record

Blood loss and replacement In general, blood volume is

approximately 100 to 120 mL/kg for a preterm infant, 90 mL/kg for a full-term infant, 80 mL/kg for a child 3 to 12 months old, and 70 mL/kg for a child older than 1 year. These are merely estimates of blood volume. The individual child's blood volume is calculated by simple proportion by multiplying the child's weight by the estimated blood volume (EBV) per kilogram

Maximum allowable blood loss MABL=EBV*(Starting hct-target

hct)/strting hct Volume to be transfused=(desired

hct-presenthct)8ebv/hct of prbc

Normal and acceptable hct valuePremature

40-45 35

Newborn 45-65 30-353months 30-42 25

Composition of IV fluids (per 1000 ml)

Fluid Na K Cl Glucose Others

5% dextrose

- - - 50 g -

10% dextrose

- - - 100 g -

Normal saline

154 mEq - 154 mEq - -

N/2 saline

77 mEq - 77 mEq - -

N/5 saline in

5% dextrose

30 mEq - 30 mEq 40 g -

3% saline

513 mEq - 513 mEq - -

Ringer’s lactate

130 mEq 4 mEq 109 mEq - Lactate 29

Isolyte P 26 mEq 19 mEq 22 mEq 50 g acetate 24, PO4 3,

Mg 3

Some other fluids meq/L

Fluid Na K Cl Glucose Others

Plasmalyte A

140 5 98 Mg3acetate 27

Albumin 5%

145+15 <2.5 100

Hexa starch 6%

154 154

Conclusion

Fluid therapy should be tailored to the needs of individual patient

Basal fluid and energy requirements as well as correction of derangements may be met by crystalloids

Infusion of large volume of crystalloid to correct intravascular deficit may produce tissue oedema,coagulation abnormality and organ dysfunction

conclusion

Intravascular correction should be made with crystalloids

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