Objective To compare the amplitude integrated EEG (aEEG) tracings in patients resuscitated at delivery with 21% or 100% oxygen.
Methods The aEEG tracings of neonates resuscitated at delivery that were randomly assigned to resuscitation with 21% oxygen (30 cases) or 100% oxygen (30 cases) were compared. There were noted: the type of encephalopathy (Sarnat classification), the background patterns at 2 h, 24 h, 72 h, the time of appearance of sleep–wake cycles (SWC), the seizure type and the time of cessation of seizures.
Results Normal SWC appeared earlier in the 21% oxygen group: 14.8 h (+6.36 h) than in the 100% oxygen group 22.7 h (+12.2 h) (p<0.03) when the entire sample was compared, and also in the case of Sarnat 1 patients: 5.63 h (+1.39 h) versus 7.95 h (+1.56 h) (p<0.027), Sarnat 2 patients: 29.6 h (+4.08 h) versus 52.7 h (+16.35 h) (p<0.001) but not in the case of Sarnat 3 patients. The background patterns did not differ significantly between the two groups in Sarnat 1 cases; there was a statistically significant difference in the subgroup of Sarnat 2 cases at 2 h (more cases with burst suppression and flat tracings in the 100% oxygen group (p<0.02). The seizures occurred later in the 21% oxygen group compared with the 100% oxygen group: 19.33 h (+4.5 h) versus 14.28 h (+2.43 h) (p<0.26), there was no difference in the time of cessation of seizures between the groups (p<0.201).
Conclusions The patients resuscitated at delivery with 21% oxygen have an earlier appearance of the SWC, a less severe background pattern and a later moment of occurrence of seizures than the patients resuscitated with 100% oxygen. This could be related to a better neurological prognosis in the cases of birth asphyxia resuscitated with 21% oxygen.