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Fluid Managementin newborns.

Presented by : Dr. Sonali Paradhi Mhatre

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WHY FLUID MANAGEMENT ??....

• Neonatal body fluid physiology is very different from older children & adults.

• Fluid and electrolyte requirement in a newborn varies as per weight and gestation age as well as the Postnatal age of the same child.

• Term and Preterm babies vary in their fluid and electrolyte quantity requirement & compositions.

• Improper fluid and electrolyte management in newborn, by itself, can result in serious morbidity and mortality in the baby.

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Basic Physiology

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Intrauterine Physiology

Early gestation : High Total body water content & large extracellular compartment

Advancing gestation : Rapid cellular growth, Increased body solids, fat deposition.

Reductions in Total body water, reduction in ECF volume and Increase in ICF volume

Therefore, Premature infants have excess Total body fluids& ECF volume expansion.

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Body composition

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Labour and Delivery Physiology

FLUID SHIFT(From Vascular compartment to

Interstitium)

Intrapartum hypoxia – Increased Capillary

Permeability

Catecholamines, Cortisol ,

Vasopressin - Increased

Arterial Pressure

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Postnatal physiology - Immediate

Increased Oxygenation

Increased vasoactive hormone

production

Capillary Permeability restored.

Therefore, Interstitial fluid reabsorption in

vascular compartment.

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Postnatal physiology - Late

Early days – Interstitial fluid absorbtion in the intravascular compartment

Rise in circulating blood volume

Atrial Natriuretic Peptide released from heart which enhances Sodium and water excretion.

Abrupt decrease in Total Body water and resultant weight loss in baby.

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Goals of Fluid therapy in newborns:

• 1. Maintain appropriate ECF volume.

• 2. Maintain ECF and ICF osmolality.

• 3.Maintain Ionic concentrations and

pH.

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Steps :

• 1. Estimating existing deficits or excess.

• 2. Ongoing maintainance needs calculations.

• 3. Supplying additional needs & Ongoing losses.

Sensible fluid loss Insensible fluid loss

supply

FLUID

IV

ORAL

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WATER LOSS

SENSIBLE

Kidney GIT

INSENSIBLE

Skin

70%Respiratory Tract 30%

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Insensible water loss

• Known as "insensible water loss" as it is a process over which organisms have little physiological control.

• Includes transepidermal water loss and fluid loss through respiratory tract.

• IWL PRETERM>TERM

Reasons : Immaturity of Skin Barrier

Respiratory Distress

Larger body water content

More surface area for fluid loss.

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Insensible water loss (cont…..)

• Gestational age, postnatal age and environmental factors determine amount of IWL.

• Ambient humidity is one of the greatest determinants of IWL.

• Other environmental factors include activity, airflow, elevated body, and environmental temperature, skin breakdowns & mucosal defects like seen in gastrochisis,etc.

• Respiratory IWL is mainly dependant on the temperature and humidity of the inspired gas, respiratory rate and tidal volume and dead space ventillation.

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Insensible water loss (cont…..)

* IWL values increased approximately upto 30% with Phototherapy exposure.

* Radiant warmers increase IWL by approx 50%.

Age (d)

Birth weight Range (kg)

0.50-0.75 0.75-1 1-1.25 1.25-1.50 1.5-1.75 1.75-2

0-7 100 65 55 40 20 15

7-14 80 60 50 40 30 20

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Factors affecting Insensible water loss

Factors Effects on IWL

Maturity Inversely proportional to birth wt. and gestational

age.

Radiant warmer Increased – 50%

Phototherapy Increased – 30%

High humidity Decreased – 30%

Plastic heat shield Decreased – 30%

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Ways to Minimise IWL• Incubator use (min 50 % humidity).• Humidification of inspired gases in head box and

ventilators.

• Thermoneutral temperature.• Increased ambient humidity

• Thin transparent plastic barrier.• Local oil application to minimise evaporative losses.• Minimal use of stickings on baby skin and proper newborn

skin care.

• Humidified ventillator gases.

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Assessment

• HISTORY.........

• Body weight daily recording and charting.• Tachycardia – may indicate hypo/hypervolemia.• Perfusion – capillary refill time.• Edema• Hepatomegaly• Blood pressure • Skin turgor, mucus membrane dryness, AF – non reliable.• Decreased urine output. • Systemic examination to look for RDS, CHD, BPD

changes fluid calculations

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Laboratory Parameters

• Serum electrolytes : Serum Na+ and K+ on admission and day3.

Every alternate day estimation for ventillated /

unstable baby.

Twice a week for other babies on IV Fluids.

• BUN and Creat twice a week.

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Laboratory Parameters

.

• Glucose estimation twice a day for ventillated

or unstable babies. Rest – once daily.

• Plasma osmolarity . Normal : 280-300mosm/l

• Urine specific gravity : 1.008 – 1.012 and correlate

with plasma osmolarity for ventillated/ sick babies.

• Blood gas analysis, septic workup for dehydrated

baby.

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Maintainance fluids

Birth weight

(kg)

Dextrose (conc)

Fluid Rate (ml/kg/day)

< 24 hrs 24 – 48 hrs > 48 hrs

< 1.0 5 – 10 100 120 140

1.0 – 1.5 10 80 100 120

> 1.5 10 60 80 100Add maintainance calcium from day1

Electrolytes to be added after 48 hours of life. During 1st wk, requirement of Na+,K+, Cl is 1-2 mEq/kg/d and beyond first wk,

2-3mEq/kg/d.

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Appropriate fluid & electrolyte balance

.Normal urine output : 1- 3 ml/kg/hr

Urine specific gravity : 1008 – 1012

Weight loss of 5% in term and 15% in preterm babies.

A weight loss of 2 – 3% per day is expected in the first week of life.

Normal serum electrolytes.

Normal weight graph on charts.

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Special Circumstances

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Respiratory distress syndrome

Consists of 3 phases – prediuretic phase (stabilization phase), Diuretic phase (Restriction maintainance phase), Post diuretic (liberalization phase.)

WHAT TO DO ???

1. Fluid restriction to 2/3rd of maintainanceduring the initial phase. After diuresis occurs, fluid rate can be cautiously increased.

2. Prevent hypoglycemia. Shock can be treated with normal saline ± ionotropes.

3. Full maintainance fluids can be achieved at the end of first week once initial diuresis is completed.

4. Special care to be taken for calculating the insensible fluid losses and supplying it.

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Birth asphyxia

Oliguria or anuria may be seen in these babies secondary to SIADH or renal injury.

WHAT TO DO ???

1. Fluid restriction to 2/3rd of maintainance during period of anuria.

2. Restore fluid intake to normal when urine production is normal.

3. Fluid push (20cc/kg Normal saline) can be given if pre renal cause suspected.

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PDA (only if symptomatic)

Patent ductus arteriosus need fluid restriction only if signs of failure are present – tachycardia, hepatomegaly, edema, sudden weight gain.

WHAT TO DO ???

1. Supply 2/3rd of total maintainance fluid.

2. Iv frusemide may be given SOS.

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Thank you!!