Changing trend of abdominal regional oxygen saturation in very/extremely low birth weight infants in the early postnatal stage: a prospective study

Objectives: To study the changing trend of abdominal regional oxygen saturation (A-rSO₂) in very/extremely low birth weight (VLBW/ELBW) infants after birth.

Methods: The VLBW/ELBW infants who were admitted to the neonatal intensive care unit from September 2019 to May 2021 were enrolled as subjects. Near-infrared spectroscopy was used to monitor A-rSO₂ since day 1 after birth for 4 weeks. According to gestational age, the infants were divided into a low gestational age (<29 weeks) group and a high gestational age (≥29 weeks) group. The two groups were compared in terms of A-rSO₂ within 4 weeks after birth.

Results: A total of 63 VLBW/ELBW infants were enrolled, with 30 infants in the <29 weeks group and 33 in the ≥29 weeks group. A-rSO₂ fluctuated within the first 2 weeks after birth in the 63 infants and had the lowest level of 47.9% on day 1 after birth and then gradually increased, reaching the peak level of 67.4% on day 4; it gradually decreased on days 5-9, then gradually increased, and became relatively stable 2 weeks after birth. The ≥29 weeks group had significantly higher A-rSO₂ than the <29 weeks group at weeks 1 and 2 after birth (P<0.05), while there was no significant difference in A-rSO₂ between the two groups at weeks 3 and 4 after birth (P>0.05).

Conclusions: In infants with VLBW/ELBW, A-rSO₂ fluctuates within the first 2 weeks after birth and then gradually becomes stable. A-rSO2 is associated with gestational age within 2 weeks after birth.