fluid management in the paediatric patient anaesthetist consideration
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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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