Fetal Hemoglobin, Oxygen Toxicity, Preterm Birth
Conditions
Keywords
Fetal hemoglobin, preterm neonate, term neonate, near-infrared spectroscopy, cerebral oxygenation, peripheral oxygenation, fractional tissue oxygen extraction
Brief summary
The aim of this study is to investigate the relationship between cerebral and peripheral oxygenation and oxygen extraction, as measured by NIRS (near-infrared spectroscopy ), and the FHbF (fraction of fetal hemoglobin) and absolute HbF (fetal hemoglobin) concentration in postnatal conditions in term and preterm neonates.
Detailed description
During gestation the main fetal oxygen carrier is fetal hemoglobin (HbF). HbF exhibits a significantly higher affinity for oxygen when compared to adult hemoglobin (HbA), which makes it more suitable for oxygen extraction at the lower partial oxygen pressures in utero. Although the regulation of HbF expression is determined developmentally, recent studies report a respectable variation in the fraction of HbF in neonates. Such data suggest that the differences in HbF expression could affect end-tissue oxygenation in neonates. The methodology for measuring oxygen saturation and extraction in cerebral and peripheral tissues of neonates using the near-infrared spectroscopy (NIRS) has been well practiced in our study group. However, the method has not yet been used to investigate whether the fraction of fetal hemoglobin (FHbF) plays a significant role in cerebral and peripheral oxygenation in neonates. The aim of this study is to investigate the relationship between cerebral and peripheral oxygenation and oxygen extraction, as measured by NIRS, and the FHbF and absolute HbF concentration in postnatal conditions in term and preterm neonates.
Interventions
DEVICENear-infrared spectroscopy
For NIRS measurements the t-NIRS 1 and NIRO 200 NX (Hamamatsu, Japan) will be used. A cerebral sensor will be placed and fixed with a CPAP (Continuous Positive Airway Pressure) cap on the left forehead and a peripheral sensor on the right forearm. Duration of measurement will be two hours.
Sponsors
Medical University of Graz
Study design
Observational model
OTHER
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
2 Days to 3 Weeks
Healthy volunteers
Yes
Inclusion criteria
* Term and preterm neonates admitted to the neonatal intensive care unit (NICU) * Decision to conduct full life support * Written informed consent
Exclusion criteria
* No decision to conduct full life support * No written informed consent * Congenital malformations * Family history of haemoglobinopathies (e.g. sickle cell anaemia, thalassaemia)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| FHbF (%) | First two weeks after birth | Fraction of fetal hemoglobin in percentage |
| HbF (g/dL) | First two weeks after birth | Fetal hemoglobin concentration in g/dL |
| Change of cTOI | at specific time points (2nd-3rd 6th-8th, 12th-14th day after birth) | cerebral tissue oxygenation index (cTOI) |
| Change of pTOI | at specific time points (2nd-3rd 6th-8th, 12th-14th day after birth) | peripheral tissue oxygenation index (pTOI) |
| Change of cFTOE | at specific time points (2nd-3rd 6th-8th, 12th-14th day after birth) | cerebral fractional tissue oxygen extraction (cFTOE) |
| Change of pFTOE | at specific time points (2nd-3rd 6th-8th, 12th-14th day after birth) | peripheral fractional tissue oxygen extraction (pFTOE) |
Countries
Austria
Outcome results
None listed