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Peripheral muscle fractional tissue oxygen extraction in stable term and preterm neonates during the first 24 h after
Christina H Wolfsberger1,2, Nina Höller1,2, Nariae Baik-Schneditz1,2
1Division of Neonatology, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria.
Insights
Peripheral muscle fractional tissue oxygen extraction (pFTOE) reference values were established in stable neonates within 24 hours of birth. These normal pFTOE values remained stable across four 6-hour periods in both term and preterm infants.
Area of Science:
- Neonatal physiology
- Medical technology
- Biomedical engineering
Background:
- Peripheral muscle fractional tissue oxygen extraction (pFTOE) measures oxygen delivery and consumption dynamics.
- Establishing normal pFTOE values in neonates is crucial for clinical and research applications.
Purpose of the Study:
- To determine reference values for pFTOE in stable term and late preterm neonates during the first 24 hours after birth.
- To assess the stability of pFTOE over four 6-hour intervals post-birth.
Main Methods:
- A post-hoc analysis of prospective observational studies was conducted.
- Stable neonates without infection, asphyxia, or medical support were included.
- Peripheral muscle tissue oxygenation index (pTOI) was measured using NIRO200/NIRO200NX, and pFTOE was calculated using arterial oxygen saturation (SpO2).
Main Results:
- Data from 240 neonates (55 term, 185 late preterm) were analyzed.
- In term neonates, mean pFTOE ranged from 0.220 to 0.264 across the four periods.
- In preterm neonates, mean pFTOE ranged from 0.225 to 0.238 across the four periods.
- No significant changes in pFTOE were observed between the time periods in either group.
Conclusions:
- Reference values for pFTOE in stable term and late preterm neonates were successfully established.
- The study confirmed the stability of pFTOE within the first 24 hours post-birth.
- These normal values are essential for interpreting pFTOE in scientific and potential clinical contexts.
Background:
Peripheral muscle fractional tissue oxygen extraction (pFTOE) represents the relative extraction of oxygen from the arterial to venous compartment, providing information about dynamic changes of oxygen delivery and oxygen consumption. The aim of the present study was to establish reference values of pFTOE during the first 24 h after birth in stable term and late preterm neonates.
Methods:
The present study is a post-hoc analysis of secondary outcome parameters of prospective observational studies. Only stable neonates without infection, asphyxia and any medical support were eligible for our analysis to obtain normal values. For measurements of peripheral muscle tissue oxygenation index (pTOI) during the first 24 h after birth in term and preterm neonates, the NIRO200/NIRO200NX was used. Arterial oxygen saturation (SpO2) was obtained by pulse oximetry. pFTOE was calculated out of pTOI and SpO2: pFTOE = (SpO2-pTOI)/SpO2. Measurements of neonates were stratified into four groups according to their respective measurement time point (6 h periods) after birth. Term and preterm neonates were analyzed separately. Mean values of measurements during the first time period (0-6 h after birth) were compared to measurements of the following time periods (second = 7-12 h, third = 13-18 h, fourth = 19-24 h after birth).
Results:
Two-hundred-fourty neonates (55 term and 185 late preterm neonates) had at least one peripheral muscle NIRS measurements within the first 24 h after birth. Mean gestational age and birth weight were 39.4 ± 1.1 weeks and 3360 (2860-3680)g in term neonates and 34.0 ± 1.4 weeks and 2060 (1750-2350)g in preterm neonates, respectively. In term neonates pFTOE was 0.264 (0.229-0.300), 0.228 (0.192-0.264), 0.237 (0.200-0.274) and 0.220 (0.186-0.254) in the first, second, third and fourth time period. In preterm neonates pFTOE was 0.229 (0.213-0.246), 0.225 (0.209-0.240), 0.226 (0.210-0.242) and 0.238 (0.222-0.255) in the first, second, third and fourth time period. pFTOE did not show any significant changes between the time periods, neither in term nor in preterm neonates.
Conclusion:
We provide reference values of pFTOE for stable term and late preterm neonates within the first 24 h after birth, which were stable when comparing four 6-h periods. These normal values are of great need for interpreting pFTOE in scientific context as well as for potential future clinical applications.
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