Race, hypoxaemia and oxidative stress in prematurely-born infants.

Background: Disparities in neonatal respiratory outcomes in prematurely-born infants might be partially explained by racial differences and the relationship of hypoxia and oxidative stress.

Aims: To determine if Black, preterm infants were exposed more frequently to hypoxaemia compared to White infants and had a higher level of oxidative damage.

Study Design: Single-centre retrospective cohort study at King's College Hospital, London, UK between 2018 and 2021.

Subjects: Infants born before 32 completed weeks of gestational age.

Outcome Measures: The median arterial oxygen saturation (SaO) over the first seven days was measured. The maximum carboxyhaemoglobin (COHb) level for the first three days was also recorded as an index of oxidative stress.

Results: Two thousand and sixty blood gases from 87 infants (38 Black) with a median (IQR) gestational age of 26.4 (24.6-28.3) weeks were analysed. The median (IQR) SaO was not significantly different in Black [96.1 (95.2-96.8) %] compared to White infants [96.7 (95.6-97.7) %, p = 0.24]. The median (IQR) COHb was not significantly different in Black infants [1.9 (1.7-2.4) %] compared to White infants [1.9 (1.7-2.3) %, p = 0.77]. The highest COHb was significantly related to the median SaO in all infants (r = -0.51, p < 0.001) and separately in Black (r = -0.50, p = 0.002) and White (r = -0.56, p < 0.001) infants.

Conclusions: Preterm, Black infants were not exposed more frequently to hypoxaemia compared to White infants. Lower saturation levels were associated with higher maximum carboxyhaemoglobin levels indicating a higher risk of oxidative stress, irrespective of racial background.