Cerebral tissue oxygen desaturations and increased fractional oxygen extraction events vary by gestational age in preterm infants

Abstract

Background and objectives

Cerebral tissue oxygen saturation (SctO₂) and cerebral fractional tissue oxygen extraction (cFTOE) changes with GA in preterm infants. This study examines changes in frequency, duration, and severity of SctO₂ desaturation and increased cFTOE with GA.

Study design

The lower limit of normal SctO₂, the event threshold, was calculated using a tolerance interval method with 95% confidence interval (CI) and 90% probability. Cerebral desaturation events were defined as: 1) a drop below event threshold for at least 30 s (s), 2) preceded by a period above the event threshold for at least 30s, and 3) followed by a period above the threshold for at least 60s.

Results

86% of infants <28 wk experienced one or more SctO₂ desaturation event compared to 57% in >28 wk, odds ratios (OR) 4.5 (CI:1.3–15.3, p = 0.016). The severity of SctO₂ desaturation events decreases at a rate of 77.9 units per wk increase in GA (p < 0.001). 39.3% of infants <28 wk experienced one or more increased cFTOE events compared to 28.6% in >28 wk, OR 1.6 (CI:0.6–4.4, p = 0.35). The severity of increasing cFTOE events decreased by 69.7 units per wk increase in GA (p < 0.001).

Conclusion

Cerebral tissue oxygen desaturation events decrease in frequency and severity with increasing GA. The severity of increased cFTOE episodes decrease with GA.