S. Kutzsche et al., Hydrogen peroxide production in leukocytes during cerebral hypoxia and reoxygenation with 100% or 21% oxygen in newborn piglets, PEDIAT RES, 49(6), 2001, pp. 834-842
The aim of this study was to investigate whether reoxygenation with 21% O-2
rather than 100% O-2 results in reduced hydrogen peroxide (H2O2) concentra
tions in neutrophils (PMN). Piglets (2-4 d old) exposed to severe hypoxia (
inspired fraction of oxygen, 0.08) were randomized to resuscitation with 21
(n = 13) or 100% O-2 (n = 12). Five animals served as controls. H2O2 conce
ntrations in PMN in terms of rhodamine 123 CRho 123) fluorescence intensity
from arterial and superior sagittal sinus blood were quantified by flow cy
tometry. Laser Doppler flowmetry (LDF) was used to assess cortical blood pe
rfusion. During hypoxia, Rho 123 increased in arterial PMN in both study gr
oups by 15 and 32%, respectively (p < 0.05). In cerebral venous PMN, the in
crease was less dominant (p = 0.06). Reoxygenation with 100 or 21% O-2 had
no different effect on Rho 123 in arterial PMN, In cerebral venous PMN, Rho
123 was approximately 40% higher after 60 min and 30% higher after 120 min
compared with corresponding data in the 21% O-2 group (p < 0.05), which we
re close to baseline levels, Further, O-2 treatment in both groups induced
PMN accumulation in arterial blood (p < 0.05). Laser Doppler flowmetry sign
als increased during transient hypoxia (p < 0.0001 compared with baseline)
and were normalized after reoxygenation in both study groups. In conclusion
, arterial and cerebral venous H2O2 concentration in PMN tended to increase
during hypoxia. During reoxygenation, H2O2 concentration in PMN in the cer
ebral circulation was low with 21% O-2 but remained high with 100% O-2 vent
ilation. We speculate that oxygen should be reintroduced with more caution
during neonatal resuscitation.