Original article
Outcomes of hypoxic ischaemic encephalopathy treated with therapeutic hypothermia using cool gel packs – Experience from Western Australia

https://doi.org/10.1016/j.ejpn.2014.02.003Get rights and content

Abstract

Therapeutic hypothermia is the standard clinical practice for neonates with moderate to severe hypoxic ischaemic encephalopathy (HIE).

Aim

To describe the two year neurodevelopmental outcomes of neonates who were routinely cooled using cool gel packs for HIE in Western Australia.

Methods

Retrospective study. Cases were identified from the neonatal databases. Information was collected from chart review.

Results

65 infants received therapeutic hypothermia, of which 13 had mild, 35 moderate and 17 had severe HIE. There were no serious adverse effects attributable to cooling. All 13 infants with mild HIE survived, of whom developmental outcomes were available on nine; none had severe disability. Among 52 infants with moderate to severe HIE, there were nine deaths (17%) and developmental outcomes were available on 39; the incidence of severe disability was 23%. The risk of death or severe disability was 40% in infants with moderate to severe HIE. Physical growth was adequate at two years of age.

Conclusions

Neonates undergoing therapeutic hypothermia with cool gel packs had both good survival rates and long term neurodevelopmental outcomes and met international benchmarks.

Introduction

Moderate-to-severe hypoxic ischaemic encephalopathy (HIE) occurs at an approximate rate of 1–2 per 1000 live births1, 2 and carries a high risk of mortality and long term disability.3, 4, 5 Systematic reviews of randomized trials have shown that therapeutic hypothermia decreases mortality and neurodevelopmental disability in infants with moderate to severe HIE.1, 6, 7, 8 The fetal and newborn committee of the Canadian Pediatric Society recommends the use of whole body cooling (rectal temperature of 34 ± 0.5 °C) or selective head cooling initiated as soon as possible within the first 6 h of life in infants with moderate HIE who are ≥36 weeks' gestational age.9Our neonatal units have been offering therapeutic hypothermia since January 2008. We conducted this retrospective study to evaluate the long term outcomes of neonates who underwent therapeutic cooling for hypoxic ischaemic encephalopathy.

Section snippets

Patient population

All infants who underwent therapeutic hypothermia for HIE between 1st January 2008 and 30th June 2010 were identified from the neonatal database. Relevant information was obtained by reviewing the medical records of patients, the laboratory database and the neonatal follow up program database.

Clinical protocol of cooling

The infants were eligible for cooling if they met the following criteria:-

  • 1.

    ≥35 weeks gestational age

  • 2.

    <6 h of age

  • 3.

    evidence of asphyxia as defined by at least 2 of the following 4 criteria –

    • a.

      Apgar Score <6 at

Results

68 infants were treated with therapeutic hypothermia during the study period. Three were excluded: 1 because of mitochondrial cytopathy, second one had a massive intra abdominal tumour requiring chemotherapy in the 1st few days of life and the 3rd infant had congenital hypopituitarism and septo-optic dysplasia. The remaining 65 were included in the study.

The maternal and obstetric details are given in Table 1. In nineteen cases there was a clear sentinel perinatal event: seven had shoulder

Discussion

We have reported on the long term outcomes of 65 neonates with HIE who were managed using the manual method of cool gel packs. To our knowledge it is the second study reporting on the long term outcomes of using cool gel packs outside clinical trial set up. The other study was by Koshy et al. from India14 who reported neurodevelopmental outcomes at 18–24 months of age in infants who were cooled using cool gel packs. Only 3/15 (20%) had an adverse outcome (2 death and 1 disability) in their

Conclusions

Neonates undergoing therapeutic hypothermia with cool gel packs had both good survival rates and long term neurodevelopmental outcomes. These results were similar to international randomized trials.

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