Inflammation increases vulnerability to hypoxia in newborn piglets: Effect of reoxygenation with 21% and 100% O2

Objective The purpose of this study was to assess whether inflammation increases vulnerability to hypoxia, and influences the effect of 100% O2 and 21% O2 reoxygenation on brain. Study design Newborn piglets (n = 31) were randomized to 4 interventional groups: pretreatment with saline or endotoxin. After hypoxia they were reoxygenated with 21% or 100% oxygen for 30 minutes, followed by 21% oxygen for all groups. To assess brain injury we measured extracellular brain tissue glucose, glycerol, and lactate/pyruvate by microdialysis, brain tissue oxygen tension, and laser Doppler flow. Results Administration of endotoxin reduced the time to reach base excess (BE) −20 mmol/L by median 32 minutes compared with saline (P< .05). We found no differences in changes in biochemical markers, brain tissue microcirculation, or oxygen tension between piglets in the 4 groups. Conclusion Endotoxin and hypoxia acted synergistically in inducing metabolic acidosis. In the presence of experimental inflammation, 21% oxygen seems as effective as 100% O2 in reoxygenating piglets.