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Updated: Sep 24, 2025
Transcutaneous Microcirculatory Imaging in Preterm Neonates
Published on: December 31, 2015
Clinical determinants of cerebrovascular reactivity in very preterm infants during the transitional period
Silvia Martini1,2, Marek Czosnyka3, Peter Smielewski3
1Neonatal Intensive Care Unit, IRCCS S. Orsola-Malpighi Hospital, Bologna, Italy. silvia.martini9@unibo.it.
Insights
Impaired cerebrovascular reactivity in preterm infants, indicated by TOHRx, is linked to dopamine treatment, low blood pressure, and patent ductus arteriosus. This finding may help develop neuroprotective strategies for vulnerable newborns.
Area of Science:
- Neonatal physiology
- Cerebrovascular regulation
- Neuroprotection
Background:
- Preterm infants face heightened risk of brain injury due to altered cerebral hemodynamics post-birth.
- Postnatal transition presents challenges to maintaining stable cerebral blood flow in premature neonates.
Purpose of the Study:
- To assess clinical factors influencing cerebrovascular reactivity during the postnatal transition in preterm infants.
- To investigate the association between cerebrovascular reactivity and the development of intraventricular hemorrhage (IVH).
Main Methods:
- Continuous monitoring of cerebral oxygenation and heart rate in preterm infants (<32 weeks) for 72 hours.
- Calculation of the TOHRx (correlation coefficient between cerebral oxygenation and heart rate) as a measure of cerebrovascular reactivity.
- Analysis of clinical variables, ductal status, and IVH development using linear mixed-effect models.
Main Results:
- Hemodynamically significant patent ductus arteriosus (hsPDA) and dopamine treatment correlated with increased TOHRx, indicating impaired reactivity.
- Mean arterial blood pressure and CRIB-II score were significantly associated with TOHRx.
- Infants who developed high-grade IVH exhibited significantly higher TOHRx compared to those without IVH.
Conclusions:
- Impaired cerebrovascular reactivity in preterm infants is associated with dopamine, low blood pressure, hsPDA, and high CRIB-II scores.
- Understanding these factors can inform individualized neuroprotective strategies for at-risk preterm infants.
- Elevated TOHRx in infants with high-grade IVH supports the role of impaired cerebrovascular reactivity in IVH pathophysiology.
Background:
Preterm infants are at enhanced risk of brain injury due to altered cerebral haemodynamics during postnatal transition. This observational study aimed to assess the clinical determinants of transitional cerebrovascular reactivity and its association with intraventricular haemorrhage (IVH).
Methods:
Preterm infants <32 weeks underwent continuous monitoring of cerebral oxygenation and heart rate over the first 72 h after birth. Serial cranial and cardiac ultrasound assessments were performed to evaluate the ductal status and to diagnose IVH onset. The moving correlation coefficient between cerebral oxygenation and heart rate (TOHRx) was calculated. Linear mixed-effect models were used to analyse the impact of relevant clinical variables on TOHRx. The association between TOHRx and IVH development was also assessed.
Results:
Seventy-seven infants were included. A haemodynamically significant patent ductus arteriosus (hsPDA) (β = 0.044, 95% CI: 0.007-0.081) and ongoing dopamine treatment (β = 0.096, 95% CI: 0.032-0.159) were associated with increasing TOHRx, indicating impaired cerebrovascular reactivity. A significant association between TOHRx, mean arterial blood pressure (β = -0.004, 95% CI: -0.007, -0.001) and CRIB-II score (β = 0.007, 95% CI: 0.001-0.015) was also observed. TOHRx was significantly higher in infants developing high-grade IVH compared to those without IVH.
Conclusions:
Dopamine treatment, low blood pressure, hsPDA and high CRIB-II are associated with impaired cerebrovascular reactivity during postnatal transition, with potential implications on IVH development.
Impact:
The correlation coefficient between cerebral oxygenation and heart rate (TOHRx) provides a non-invasive estimation of cerebrovascular reactivity, whose failure has a potential pathogenic role in the development of IVH in preterm infants. This study shows that cerebrovascular reactivity during the transitional period improves over time and is affected by specific clinical and therapeutic factors, whose knowledge could support the development of individualized neuroprotective strategies in at-risk preterm infants. The evidence of increased TOHRx in infants developing high-grade compared to low-grade or no IVH during the transitional period further supports the role of impaired cerebrovascular reactivity in IVH pathophysiology.
