Changes in regional oxygen saturation of the kidney and brain of infants during hospitalization.

BACKGROUND

In pre-term infants, the postnatal changes in the regional oxygen saturation (rSO2) of the brain and kidney are unclear.

METHODS

We performed a prospective observational study. We measured the cerebral/renal rSO2 ratio and recorded the associated clinical features of infants born at 23 to 41 weeks of gestation weekly from the early postnatal period to discharge.

RESULTS

The median cerebral/renal rSO2 ratios (interquartile ranges) between birth and the expected date of birth were 1.13 (1.06-1.26) at 23-24 weeks (n = 7), 1.18 (1.10-1.32) at 25-26 weeks (n = 11), 1.24 (1.11-1.37) at 27-28 weeks (n = 9), 1.12 (1.05-1.19) at 29-30 weeks (n = 4), 1.11 (1.03-1.15) at 31-32 weeks (n = 5), 1.02 (0.98-1.06) at 33-34 weeks (n = 9), 0.98 (0.94-1.06) at 35-36 weeks (n = 19), and 0.95 (0.86-0.99) at 37-41 weeks of gestation (n = 22). The median cerebral/renal rSO2 ratio did not significantly change after birth, but with increasing gestational age, the cerebral/renal rSO2 ratio at the expected date of birth decreased (r = - 0.74, p < 0.001). Nephrotoxic drugs did not affect cerebral/renal rSO2 at the expected date of birth, after adjustment for clinical factors.

CONCLUSIONS

Unlike in most infants born after the late pre-term period, the renal rSO2 remained lower than the cerebral rSO2 on the expected date of birth in infants born very pre-term.