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Progressive anemia of prematurity is associated with a critical increase in cerebral oxygen extraction
Halana V Whitehead1, Zachary A Vesoulis1, Akhil Maheshwari2
1Department of Pediatrics, Division of Newborn Medicine, Washington University School of Medicine, United States of America.
Insights
Elevated cerebral oxygen extraction (cFTOE) in premature infants indicates adaptation to anemia. A critical increase in cFTOE occurs at a hemoglobin level of 9.6 g/dL, suggesting a new threshold for transfusion in anemia of prematurity.
Area of Science:
- Neonatal physiology and brain oxygenation.
- Understanding physiological adaptations in preterm infants.
Background:
- Anemia of prematurity (AOP) is common in preterm infants.
- Elevated cerebral fractional tissue oxygen extraction (cFTOE) is a compensatory mechanism for AOP.
- cFTOE ≥0.4 is linked to brain injury in infants ≤30 weeks gestational age.
Purpose of the Study:
- To investigate the utility of cFTOE in evaluating AOP.
- To determine the relationship between hemoglobin levels and cFTOE in preterm infants.
- To identify a critical threshold of cFTOE associated with AOP.
Main Methods:
- Longitudinal study of infants ≤30 weeks estimated gestational age (EGA).
- Weekly hemoglobin, cerebral saturation, and pulse oximetry recordings from 2 to 36 weeks post-menstrual age (PMA).
- Statistical analysis included linear mixed-effects modeling and receiver operating characteristic (ROC) analysis.
Main Results:
- 144 recordings from 39 infants were analyzed.
- A significant negative correlation was found between hemoglobin and cFTOE (R = -0.423, p ≤ 0.001).
- ROC analysis showed an area under the curve (AUC) of 0.821, with a critical cFTOE increase at hemoglobin 9.6 g/dL.
Conclusions:
- Anemia of prematurity is associated with a critical increase in cFTOE.
- This critical increase occurs at a higher hemoglobin level than current transfusion thresholds.
- cFTOE may serve as a valuable indicator for managing AOP and preventing brain injury.
Background:
Elevated cerebral fractional tissue oxygen extraction (cFTOE) is an adaptation to anemia of prematurity (AOP). cFTOE ≥0.4 is associated with brain injury in infants ≤30 weeks. This longitudinal study sought to investigate the utility of cFTOE in the evaluation of AOP.
Methods:
Infants ≤30 weeks estimated gestational age (EGA) underwent weekly hemoglobin, cerebral saturation, and pulse oximetry recordings from the second through 36 weeks post-menstrual age (PMA). Recordings were excluded if they were under 1 h or if hemoglobin was not measured within 7 days of recording. Mean cFTOE was calculated for each recording. Statistical analysis used linear mixed-effects modeling and receiver operating characteristic analysis.
Results:
144 recordings from 39 infants (mean EGA 27.6 ± 2.2 weeks, BW 1139 ± 286 g) were included of whom 39% (15/39) were transfused. The mean recording length was 2.8 ± 1.3 h. There was a significant negative correlation between hemoglobin and cFTOE (R = -0.423, p ≤.001). In a multivariate model, adjusting for EGA, PMA, and patent ductus arteriosus treatment the AUC was 0.821. A critical increase in cFTOE occurred at a hemoglobin level of 9.6 g/dL.
Conclusions:
AOP is associated with a critical increase in cFTOE that occurs at a significantly higher hemoglobin level than standard clinical thresholds for transfusion.
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