Inhaled H_2 or CO_2 Do Not Augment the Neuroprotective Effect of Therapeutic Hypothermia in a Severe Neonatal Hypoxic-Ischemic Encephalopathy Piglet Model
Kovács V, Remzső G, Tóth-Szűki V, Varga V, Németh J, Domoki F. · 2020.
Study at a glance
Preclinical
Newborn piglets with severe experimental hypoxic-ischemic encephalopathy receiving therapeutic hypothermia.
5% H₂ or CO₂ inhalation added to therapeutic hypothermia. · 5% H₂ in the article-specific ventilatory mixture.
Acute treatment with five-day survival follow-up.
The article reports that adding inhaled H₂ did not improve the main neuroprotective outcomes beyond therapeutic hypothermia in this severe model.
Preclinical neonatal model; small arms, multiple outcomes and gas exposure tied to mechanical ventilation.
What kind of evidence is this?
Preclinical
Controlled neonatal-piglet hypoxic-ischemic study
Other neurological conditions
Inhaled H₂
No added neuroprotective signal over hypothermia.
Animal functional, histological and biomarker outcomes.
Methods
Newborn piglets with severe experimental hypoxic-ischemic encephalopathy receiving therapeutic hypothermia.
48 piglets across control, hypothermia and gas-treatment arms and analytical subsets.
Acute treatment with five-day survival follow-up.
5% H₂ or CO₂ inhalation added to therapeutic hypothermia.
Inhaled molecular H₂.
5% H₂ in the article-specific ventilatory mixture.
Absolute H₂ flow was not reported separately from ventilation.
Oxygen was delivered as clinically required within the ventilation protocol.
Therapeutic hypothermia alone and CO₂ comparison arms.
Outcomes and reported result
Neurological function, brain histology, seizures and biochemical measures.
The article reports that adding inhaled H₂ did not improve the main neuroprotective outcomes beyond therapeutic hypothermia in this severe model.
The full article was checked for methods, intervention details, outcomes, positive and null findings, funding and conflicts. This record does not imply medical efficacy.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Preclinical neonatal model; small arms, multiple outcomes and gas exposure tied to mechanical ventilation.
The reported piglet model and hypothermia protocol only.
SYRCLE animal-study tool — preliminary
Some concerns
Controlled groups were used, but group attrition, small samples and incomplete blinding create some concerns.
Sequence generation checked where reported · Allocation concealment generally unclear · Personnel blinding generally unclear · Outcome-assessor blinding generally unclear · No prospectively registered analysis plan identified
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 32948011 · DOI: 10.3390/ijms21186801
A free full article is available through PubMed Central.
Official PubMed Central full article and PubMed bibliographic record; source identity, methods, intervention, results, funding and conflicts checked 10 August 2026.
10 August 2026
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