Effects of Reoxygenation (RO) Following Pneumothorax (PT) with 21% or 100% Oxygen (O) on Early Neurological Outcome (ENO) and on Cerebral Hystopathology(CH) of Newborn Piglets 1901

Abstract

PT is far more frequent in the infants than any other period of life and associations exist between PT and central nervous system damage in human newborn infants. In the present study we tested the effect of RO following PT with 21% or 100% O on ENO and on CH of newborn piglets. Methods: 26 piglets were studied. Three experimental groups were formed: Shamoperated piglets (SHAM, n: 6), piglets with RO with 21% O after PT (RO21, n: 10) and animals with RO with 100% O after PT (RO100, n: 10). In RO21 and RO100 PT were induced under anesthesia with bilateral intrapleural air insufflation and critical phase with bradyarrythmia, arterial hypotension, hypoxemia and severe combined acidosis occurred 62 ± 6 (RO21) and 65 ± 7 min (RO100)(means ± SEM) after the start of the experiments. Ten min of RO period was started with ventilation with 21% O (RO21) or 100%O (RO100). Then the spontaneously breathing animals were followed on room air (21%O) during the next four hours and neurological examinations (M. H. LeBlanc et al. Stroke, 26:1908, 1995, neurological score of 20 normal, 5 brain dead) were performed by a blinded observer at the end of the experiments. The brains were perfusion fixed through the transcardiac route then stained with hematoxilin and eosin for CH (hyperchromatic and eosinophilic-staining neurons) in different brain regions (frontal and temporal cortex, cerebellum, hippocampus, basal ganglia, pons). Results: Neurological scores from SHAM were 18 ± 0, from RO21 12.5 ± 1.7 and from RO100 9.7 ± 1.6(significant differences - ANOVA p < 0.05 - between SHAM and RO21 and RO100, significant difference between RO21 and RO100). CH showed significant damages with similar severity in all regions studied in both PT groups (RO21 and RO100) compared to data observed in SHAM (quantitative values not given).Conclusion: RO following PT with 100% O might impair ENO but did not affect CH of newborn piglets.