Resumo

BENAVIDES, Melva et al. Two-hour hyperoxia following experimental neonatal asphyxia produces morphological brain damage. An. Fac. med. [online]. 2013, vol.74, n.4, pp.273-277. ISSN 1025-5583.

Objectives: To determine the effect of 2-hour exposure to 21% O2, 40% O2 and 100% O2 on cerebral morphology in an experimental model of neonatal asphyxia. Design: Experimental study. Setting: Instituto Nacional de Salud del Niño, Lima, Peru. Biologic material: Holtzman albino rats. Interventions: A sample of 120 one week-old Holtzman albino rats (with the exception of the control group) underwent experimental asphyxia by left carotid artery ligation and then exposition to hypoxia (8% O2); thereafter rats were randomly assigned to one of the following groups: exposition for two hours to 100% O2, to 40% O2, to 21% O2, and a control group (not exposed to experimental asphyxia). Brain damage was determined by brain weight and percentage of microscopic brain area damage. Main outcome measures: Brain damage. Results: Brain weight was lower in animals with experimental hyperoxia (ANOVA, p<0.001). Microscopic damage was more frequent in the group receiving 100% O2 for two hours and with less frequency in the group receiving 40% O2 (60% versus 43.3%). The difference was statistically significant (χ² test: p<0.001). The group receiving 100% O2 had more microscopic brain damage (18.3 %) in comparison with the other groups of experimental hypoxia, but the difference was not statistically significant (ANOVA, p=0.123). Conclusions: Following neonatal asphyxia 100% two-hour hyperoxia was associated with less brain weight and more damage in experimental animals.

Palavras-chave : Asphyxia neonatorum; hyperoxia; hypoxia-ischemia brain.

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