Equis ISSN 2398-2977

Fluid therapy: neonatal

Synonym(s): Neonatal fluid therapy

Contributor(s): Mark Senior, Pamela Wilkins, Nicola Menzies-Gow

Introduction

Physiology

The newborn foal CANNOT be approached in the same way as an adult horse.

  • The newborn foal is making a transition from a fetal state to a neonatal state; this greatly affects fluid therapy management of ill foals during the first few days of life.

The fetus does not produce much urine.

  • In the fetus, less than 2% of cardiac output is going to the kidney. By day 4 of life, glomerular filtration rate (GFR) appears to approach normal adult values in the normal neonate. However, compromised foals may not make an appropriate transition. The transition can also be delayed by administration of non-steroidal anti-inflammatory drugs Therapeutics: anti-inflammatory drugs, eg flunixin meglumine Flunixin meglumine, as the distribution of blood flow in the neonatal kidney is affected by prostaglandin balance.
  • The newborn foal has a larger body water percentage than does the adult horse, reflected in part as a larger blood volume. Body water is approximately 75-80% of bodyweight in the neonate.
  • The first urine produced by a newborn foal is concentrated. Normal neonates on a milk diet produce large volumes of very dilute urine with a specific gravity Urine: specific gravity between 1.003 and 1.008. This is due to their large free water load associated with the milk diet. Normal mare milk is very low in sodium and sodium fractional excretion by the kidney is much lower in the normal foal than the adult, usually <0.3%.
  • The vascular endothelium of the fetus is more leaky than that of an older neonate or an adult. This allows the interstitial space to serve as large potential fluid reservoir and protects the fetus/newborn from large fluid losses in the immediate periparturient period. This also contributes to the edema sometimes observed in critically ill neonates.
  • The newborn foal has lower mean, systolic and diastolic arterial pressures than does the older foal or the adult. The fetus is a low pressure system and a period of adaptation occurs following birth.

Goals of fluid therapy in the neonate

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Blood and blood product therapy

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Oral fluid therapy

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Further Reading

Publications

Refereed papers
  • Recent references from PubMed and VetMedResource.
  • Dickey E J, McKenzie III H C, Johnson A and Furr M O (2010) Use of pressor therapy in 34 hypotensive critically ill neonatal foals. Australian Veterinary Journal, 88 (12), 472-7 PubMed.
  • Bentz A I, Wilkins P A, MacGillivray K C et al (2002) Severe thrombocytopenia in two thoroughbred foals with sepsis and neonatal encephalopathy. J Vet Intern Med 16 (4), 494-497 PubMed.
  • Kavvadia V, Greenough A, Dimitriou G et al (2000) Randomised trial of fluid restriction in ventilated very low birthweight infants. Arch Dis Child Fetal Neonatal Ed 83 (2), F91-96 PubMed.
  • Bell E F & Acarregui M J (2000) Restricted versus liberal water intake for preventing morbidity and mortality in preterm infants. Cochrane Database Syst Rev 2, CD000503 PubMed.
  • Wilkins P A & Dewan-Mix S (1994) Efficacy of intravenous plasma therapy for treatment of failure of passive transfer in normal and clinically ill equine neonates.  Cornell Vet 84 (1), 7-14 PubMed.

Other sources of information

  • Wilkins P A (2003) Neonatal diseases. In: Manual of Equine Emergencies. Eds: Orsini & Divers. 2nd edn. pp 541-574.
  • Jonathan E Palmer (2002) Physiologic Approach to Neonatal Fluid Therapy. In:  8th Int Vet Emerg and Crit Care Symp. San Antonio. pp 137.
  • Jonathan E Palmer (2002) Practical Approach to Fluid Therapy in Neonates.In: 8th Int Vet Emerg and Crit Care Symp. San Antonio. pp 141.


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