OBJECTIVESome research has shown that hyperbaric oxygen (HBO) can decrease the rate of mortality and disability caused by hypoxic-ischemic encephalopathy (HIE) in neonates. However, the HBO pressure used in the clinical reports and the efficacy of HBO are different. This study was designed to investigate the efficacy of HBO therapy under different pressures by observing the changes of peroxidation, antioxidant levels and brain vasomotor regulation factors as well as the score of neonatal behavioral neurological assessment (NBNA) in neonates with HIE after HBO therapy.

METHODSSixty neonates with HIE were randomly administered with 1.4, 1.5 or 1.6 atmosphere absolute (ATA) of HBO, once daily for seven days. Serum levels of malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO) and nitric oxide synthase (NOS) were measured before and after HBO therapy. Meanwhile, NBNA and eye ground examination were performed.

RESULTSSerum SOD level increased and serum levels of MDA, NO and NOS decreased significantly after HBO therapy in the three HBO therapy groups (P<0.01). Serum SOD level was significantly higher and serum levels of MDA, NO and NOS were significantly lower in the 1.6 ATA HBO group than those in the 1.4 ATA group after therapy (P<0.05). The 1.6 ATA HBO group also showed increased SOD and decreased MDA levels compared with the 1.5 ATA HBO group after therapy (P<0.05). NBNA scores in the three groups increased significantly after HBO therapy (P<0.05). None of the three HBO therapy group patients showed abnormal eye grounds after therapy.

CONCLUSIONSHBO therapy with 1.4, 1.5 or 1.6 ATA is safe and effective for neonatal HIE. The antioxidant capacity increases with the increasing HBO pressure in neonates with HIE.