Paeds · fetal-neonatal-and-perinatal
Hypoxic-ischaemic encephalopathy and therapeutic hypothermia
Also known as Hypoxic-ischaemic encephalopathy and therapeutic hypothermia · Perinatal asphyxia and neonatal brain injury · Birth asphyxia encephalopathy · Neonatal hypothermia neuroprotection (cooling) · HIE
Fellowship guide to hypoxic-ischaemic encephalopathy and therapeutic hypothermia: the excitotoxic cascade and latent phase, Sarnat staging and cooling eligibility, the 6-hour window, the 72-hour cooling protocol, supportive neurocare, MRI prognostication and the adjuvant-therapy controversies.
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Red flags
- Therapeutic hypothermia for moderate-to-severe HIE must start within 6 hours of life — the window closes whether or not the infant is fully investigated, so assess eligibility the moment encephalopathy is suspected
- Cord or early blood gas pH under 7.0 or base deficit at least 12 mmol/L plus moderate-to-severe encephalopathy meets the cooling eligibility threshold — do not wait for the MRI
- Sarnat stage 3 (severe) HIE has the worst prognosis but is still cooling-eligible — severity is not a reason to withhold cooling
- Sinus bradycardia during cooling is expected and benign — it is not an indication to rewarm
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- Hypoxic-ischaemic encephalopathy and therapeutic hypothermia
- Long case: hypoxic-ischaemic encephalopathy and therapeutic hypothermia
- Communication: breaking bad news in neonatal encephalopathy
- Hypoxic-ischemic encephalopathy and therapeutic hypothermia
- Patient Care: hypoxic-ischemic encephalopathy and therapeutic hypothermia
- Medical Expert: hypoxic-ischemic encephalopathy and therapeutic hypothermia
Overview & Definition
A term newborn who is limp, silent, and not breathing at birth, and who does not recover to a normal neurological state within hours, has sustained a hypoxic-ischaemic insult to the brain. When that insult produces a clinical syndrome of disturbed neurological function in the first days of life, the diagnosis is neonatal encephalopathy; when the cause is hypoxia and ischaemia around the time of birth, it is hypoxic-ischaemic encephalopathy (HIE). [10]
Hypoxic-ischaemic encephalopathy is not simply "birth asphyxia." It is a distinct clinicopathological syndrome: a recognisable constellation of altered consciousness, abnormal tone, depressed or absent primitive reflexes, autonomic disturbance, feeding difficulty, and (often) seizures, set against a history and biochemical evidence of perinatal asphyxia. The decisive clinical task is to grade its severity quickly, because moderate and severe HIE are eligible for the one intervention proven to change outcome — therapeutic hypothermia. [1] [4]
References10ShowHide
- [1]Sarnat HB; Sarnat MS Neonatal encephalopathy following fetal distress. A clinical and electroencephalographic study. Arch Neurol, 1976.PMID 987769
- [2]Gluckman PD; Wyatt JS; Azzopardi D; Ballard R; Edwards AD; Ferriero DM; Polin RA; Robertson CM; Thoresen M; Whitelaw A; Gunn AJ Selective head cooling with mild systemic hypothermia after neonatal encephalopathy: multicentre randomised trial. Lancet, 2005.PMID 15721471
- [3]Shankaran S; Laptook AR; Ehrenkranz RA; Tyson JE; McDonald SA; Donovan EF; Fanaroff AA; Poole WK; Wright LL; Higgins RD; et al Whole-body hypothermia for neonates with hypoxic-ischemic encephalopathy. N Engl J Med, 2005.PMID 16221780
- [4]Azzopardi DV; Strohm B; Edwards AD; Dyet L; Halliday HL; Juszczak E; Kapellou O; Levene M; Marlow N; Porter E; et al Moderate hypothermia to treat perinatal asphyxial encephalopathy. N Engl J Med, 2009.PMID 19797281
- [5]Jacobs SE; Berg M; Hunt R; Tarnow-Mordi WO; Inder TE; Davis PG Cooling for newborns with hypoxic ischaemic encephalopathy. Cochrane Database Syst Rev, 2013.PMID 23440789
- [6]Shankaran S; Pappas A; McDonald SA; Vohr BR; Hintz SR; Ehrenkranz RA; Tyson JE; Das A; Hammond J; Perritt R; et al Childhood outcomes after hypothermia for neonatal encephalopathy. N Engl J Med, 2012.PMID 22646631
- [7]Barkovich AJ; Westmark KD; Partridge C; Sola A; Ferriero DM Perinatal asphyxia: MR findings in the first 10 days. AJNR Am J Neuroradiol, 1995.PMID 7793360
- [8]Laptook AR; Shankaran S; Tyson JE; Munoz B; Bell EF; Goldberg RN; Das A; Pappas A; Pedroza C; Heyne RJ; et al Effect of Therapeutic Hypothermia Initiated After 6 Hours of Age on Death or Disability Among Newborns With Hypoxic-Ischemic Encephalopathy: A Randomized Clinical Trial. JAMA, 2017.PMID 29067428
- [9]Wu YW; Mathur AM; Chang T; McKinstry RC; Mulkey SB; Shellhaas RA; Blossom S; Cunningham F; Reber C; Young A; et al Trial of Erythropoietin for Hypoxic-Ischemic Encephalopathy in Newborns. N Engl J Med, 2022.PMID 35830641
- [10]Douglas-Escobar M; Weiss MD Hypoxic-ischemic encephalopathy: a review for the clinician. JAMA Pediatr, 2015.PMID 25685948