Sudhakar AdusumilliMBBS;DCH;MRCP;FRCPCH

Division Chief & Senior Attending Physician,

Emergency Department

Sidra Medicine, Doha, Qatar

FormerlyConsultant Pediatrician and Lead Neonatologist

& Clinical Director

United Lincolnshire Hospitals, UK

ELBW – Improving Outcomes

Fluid and Electrolyte Challenges

Agenda

• What is different about ELBW• Potential problems• Fluid Management• Electrolyte Management• Take home practical messages

What is different about ELBW

• Nephron development is complete by 32 to 26 weeks of gestation (1)

• Preterm babies have more total body water and may lose 10–15% of their weight in first week of life

• Preterm babies have limited capacity to excrete sodium in first 48 hr

• Preterm babies, especially if born <29 weeks’ gestation, lose excessive sodium through immature kidneys

• Babies <28 weeks have significant trans epidermal water loss (TEW)

• TEW loss leads to hypothermia, loss of calories and dehydration, and causes excessive weight loss and hypernatremia

1. Hinchliffe SA, Sargent PH, Howard CV, Chan YF, van Velzen D. Human intrauterine renal growth expressed in

absolute number of glomeruli assessed by the disector method and Cavalieri principle. Lab Invest

1991;64:777e84

Fluid and electrolyte balance

Modi, Neena, Rennie and Roberton’s Textbook of Neonatology, 18, 331-343

Postnatal changes in bodyweight, extracellular volume and sodium balance. (Adapted from Shaffer and Weismann (1992) .)

Copyright © 2012 © 2012, Elsevier Limited. All rights reserved

Fluid and electrolyte balance

Modi, Neena, Rennie and Roberton’s Textbook of Neonatology, 18, 331-343

Weight, total body water (TBW) and body solids during the first week after birth in healthy preterm babies (dotted line) and babies with respiratory distress syndrome (solid

line). Values (mean ± 95% confidence interval) are expressed as a percent...

Copyright © 2012 © 2012, Elsevier Limited. All rights reserved

Potential Problems

• Excess fluid and sodium intakes during the first week of life has been shown to impede normal contraction of extracellular fluid, leading to an increased risk of (2,3,4)

• NEC• CLD / BPD• PDA

2. Bell EF, Warburton D, Stonestreet BS, Oh W. Effect of fluid administration on the development of symptomatic patent ductus arteriosus and congestive heart failure

in premature infants. New Engl J Med 1980;302:598e604.3. Bell EF, Warburton D, Stonestreet BS, Oh W. High volume fluid intake predisposes premature infants to necrotizing enterocolitis. Lancet 1979;2:90.

4. Bell EF, Acarregui MJ. Restricted versus liberal water intake for preventing morbidity and mortality in preterm infants. Cochrane Database Syst Rev 2008 Jan 23;(1):CD000503.

Fluid Management

• Calculate normal maintenance – Insensible Water Loss (IWL), Urine and Stools

• A number of factors affect IWL• Maturity

• Relative humidity

• Ambient temperature

• Anatomical defects

• Radiant warmers

• Phototherapy etc

FactorsAffectingIWL

Increase Decrease

Low maturity Higher maturity

Low relative humidity Increasing postnatal age

Ambient temperature exceeding neutral thermal environment

Higher ambient humidity

Skin defects Higher ventilator humidity

Phototherapy

Radiant Warmers

Body weight to Surface area

J Pediatr1978;93:62

IWL

• 1 degree F increase in ambient temperature increases IWL by 1 ml per hour

• Phototherapy (not all) and radiant warmers increase water loss

• Skin and lung related IWL is inversely related to ambient humidity

IWL

• IWL varies greatly from day to day

• Calculate this at least once in every 24 hours

• Formula to assist

Intake – Output (mainly urine in 1st week) – ( 𝝙 in Weight)

• Renal water requirement is dependent on the solute load

Urinary sodium excretion in very low birth weight infants. (From Ross BS, Cowett

RM, Oh W. Pediatric Res 1977;11:1162–4 , with permission)

First few days – Goals / Principles

• Permit isotonic contraction of EFC• Allow a brief period of negative water and sodium

balance• Fluid to permit excretion of small solute load• Account for initially high trans epidermal fluid losses• Immediate administration of Na is not required• Na can be delayed until physiological diuresis (5)• Glucose delivery should commence at around 7

mg/kg/min

5. Modi and Hutton 1990; Bétrémieux et al. 1995

A suggested fluid regimen

Term infants

(ml/kg/day)

Preterm < 1000g

(ml/kg/day)

Preterm > 1000g

(ml/kg/day)

Infants with HIE/ Acute renal failure/ SIADH(ml/kg/day)

Day 1 60 –75 60 – 90 60 – 75 40-60

Day 2 90 105 90

Day 3 105 120 105

Day 4 120 135 120

Day 5 135 150 135

Day 6 150 165 150

Day 7 onwards

150 – 200 165 – 200 165 – 200

ElectrolyteManagement - Na

• Sodium is essential for growth• Sodium to be kept between 135-145 mEq/L• No sodium in the first day or two, usually after

more than 5% of loss of birth weight• General requirement is about 3-4 mEq/Kg/Day• Be ware of large losses or kidney injury, which

alters daily needs

ElectrolyteManagement - K

• Potassium to be kept between 3.5-5.0 mEq/L• Preterm babies have higher levels of S Potassium• Potassium supplementation to be started only

after urine output is well established, usually by D3

• Start at 1-2 mEq/Kg/D and gradually increase de[ending on results

Hypovolemic Hypernatremia

Inadequate breast milk intake Diarrhea Radiant warmers Excessive sweating Renal dysplasia Osmotic diuresis

Causesof Hypernatremia

Euvolemic Hypernatremia Decreased Production of Antidiuretic Hormone Central diabetes insipidus, head trauma, central nervous system tumors (craniopharyngioma), meningitis, or encephalitis Decreased or Absence of Renal Responsiveness Nephrogenic diabetes insipidus, extreme immaturity, renal insult, and medications such as amphotericin, hydantoin, and aminoglycosides

Hypervolemic Hypernatremia Improperly mixed formula Sodium bicarbonate administration Sodium chloride administration Primary hyperaldosteronism

Causesof Hypernatremia

Causes of Hyponatremia

Water Excess – To mum or babyImpaired water excretion – Renal Failure or drugs, SIADH

Primary Sodium DepletionInsufficient IntakeExcessive lossesEndocrineGIExternal lossesCNS

Hypokalemia

• <3.0• Usually due to excess loss – Urinary due to

diuretics, tubular defects and losses via NG or Stoma

• Can cause ileus, weakness, urinary retention ECG changes

• Increase supplementation is usually sufficient

Hyperkalemia• >6• Common in VLBW• Decreased clearance• Tissue injury – IVH, Cephalhematoma,

hemolysis, bowel infarction• Excessive administration• Mx – Stop all K input• Follow local protocol for Mx of hyperkalemia

Mx of Hyperkalemia

Monitoring of baby• Overall – Gestation, Postnatal age, Environment and Illness

• Physical Exam• Accurate Weight measurement – daily or more frequently• Skin integrity

• Intake / output monitoring – hourly

• Frequent fluid balance reviews – 8 hourly in the first few day

• Bloods – Na, K, Creatinine 6-8 hourly in the first few daysDaily if on IV fluids

TakeHomeMessages

• VLBW babies are prone for more fluid and electrolyte disturbances

• Understanding the differences help in better management

• Care starts in labour room – steps to prevent heat loss and IWL

TakeHomeMessages

• Allow for Physiological ECF loss• Good quality weight measuring is essential• Humidity provision• Frequent and accurate fluid balance• Appropriate use of labs• Early identification of issues with fluid /

electrolyte imbalance

Thank You