Early oxygen-utilization and brain activity in preterm infants

The combined monitoring of oxygen supply and delivery using Near-InfraRed spectroscopy (NIRS) and cerebral activity using amplitude-integrated EEG (aEEG) could yield new insights into brain metabolism and detect potentially vulnerable conditions soon after birth. The relationship between NIRS and quantitative aEEG/EEG parameters has not yet been investigated. Our aim was to study the association between oxygen utilization during the first 6 h after birth and simultaneously continuously monitored brain activity measured by aEEG/EEG. Forty-four hemodynamically stable babies with a GA < 28 weeks, with good quality NIRS and aEEG/EEG data available and who did not receive morphine were included in the study. aEEG and NIRS monitoring started at NICU admission. The relation between regional cerebral oxygen saturation (rScO₂) and cerebral fractional tissue oxygen extraction (cFTOE), and quantitative measurements of brain activity such as number of spontaneous activity transients (SAT) per minute (SAT rate), the interval in seconds (i.e. time) between SATs (ISI) and the minimum amplitude of the EEG in μV (min aEEG) were evaluated. rScO₂ was negatively associated with SAT rate (β=-3.45 [CI=-5.76- -1.15], p=0.004) and positively associated with ISI (β=1.45 [CI=0.44-2.45], p=0.006). cFTOE was positively associated with SAT rate (β=0.034 [CI=0.009-0.059], p=0.008) and negatively associated with ISI (β=-0.015 [CI=-0.026- -0.004], p=0.007). Oxygen delivery and utilization, as indicated by rScO₂ and cFTOE, are directly related to functional brain activity, expressed by SAT rate and ISI during the first hours after birth, showing an increase in oxygen extraction in preterm infants with increased early electro-cerebral activity. NIRS monitored oxygenation may be a useful biomarker of brain vulnerability in high-risk infants.

The neonatal brain is not protected by osteopontin peptide treatment after hypoxia-ischemia

Neonatal encephalopathy due to perinatal hypoxia-ischemia (HI) is a severe condition, and current treatment options are limited. Expression of endogenous osteopontin (OPN), a multifunction glycoprotein, is strongly upregulated in the brain after neonatal HI. Intracerebrally administered OPN has been shown to be neuroprotective following experimental neonatal HI and adult stroke. In the present study, we determined whether intranasal, intraperitoneal or intracerebral treatment with a smaller TAT-OPN peptide is neuroprotective in neonatal mice with HI brain damage. The TAT-OPN peptide exerts bioactivity as it was as potent as full-length OPN in inducing cell adhesion in an in vitro adhesion assay. Intranasal administration of TAT-OPN peptide immediately after HI (T0) or in a repetitive treatment schedule of T0, 3 h, day (D) 1, 2 and 3 after HI did not protect cerebral gray or white matter after HI. Intraperitoneal TAT-OPN treatment at T0 or in two extended treatment schedules (D5, 7, 9, 11, 13, 15 after HI or T0, D1, 3, 5, 7, 9, 11, 13 and 15 after HI) did not result in neuroprotection either. Moreover, no functional improvement (cylinder rearing test and adhesive removal task) was observed following TAT-OPN treatment in any of the intraperitoneal treatment schedules. We validated that the TAT-OPN peptide reached the brain after intranasal or intraperitoneal administration by using an HIV-TAT staining. Finally, also intracerebral administration of the TAT-OPN peptide 1 h after HI did not reduce cerebral damage. Our data show that administration of the TAT-OPN peptide did not exert neuroprotective effects on neonatal HI-induced brain injury or sensorimotor behavioral deficits.

Magnesium is not consistently neuroprotective for perinatal hypoxia-ischemia in term-equivalent models in preclinical studies: a systematic review

There is an important unmet need to further improve the outcome of neonatal encephalopathy in term infants. Meta-analyses of large controlled trials now suggest that maternal magnesium sulfate (MgSO4) therapy is associated with a reduced risk of cerebral palsy and gross motor dysfunction after premature birth, but that it has no effect on death or disability. Because of this inconsistency, it remains controversial whether MgSO4 is clinically neuroprotective and, thus, it is unclear whether it would be appropriate to test MgSO4 for treatment of encephalopathy in term infants. We therefore systematically reviewed the preclinical evidence for neuroprotection with MgSO4 before or after hypoxic-ischemic encephalopathy (HIE) in term-equivalent perinatal and adult animals. The outcomes were highly inconsistent between studies. Although there were differences in dose and timing of administration, there was evidence that beneficial effects of MgSO4 were associated with confounding mild hypothermia and, strikingly, the studies that included rigorous maintenance of environmental temperature or body temperature consistently suggested a lack of effect. On balance, these preclinical studies suggest that peripherally administered MgSO4 is unlikely to be neuroprotective. Rigorous testing in translational animal models of perinatal HIE is needed before MgSO4 should be considered in clinical trials for encephalopathy in term infants.

A Critical Review of Models of Perinatal Infection

One of the central, unanswered questions in perinatology is why preterm infants continue to have such poor long-term neurodevelopmental, cognitive and learning outcomes, even though severe brain injury is now rare. There is now strong clinical evidence that one factor underlying disability may be infection, as well as nonspecific inflammation, during fetal and early postnatal life. In this review, we examine the experimental evidence linking both acute and chronic infection/inflammation with perinatal brain injury and consider key experimental determinants, including the microglia response, relative brain and immune maturity and the pattern of exposure to infection. We highlight the importance of the origin and derivation of the bacterial cell wall component lipopolysaccharide. Such experimental paradigms are essential to determine the precise time course of the inflammatory reaction and to design targeted neuroprotective strategies to protect the perinatal brain from infection and inflammation.

Development of cerebral gray and white matter injury and cerebral inflammation over time after inflammatory perinatal asphyxia

Antenatal inflammation is associated with increased severity of hypoxic-ischemic (HI) encephalopathy and adverse outcome in human neonates and experimental rodents. We investigated the effect of lipopolysaccharide (LPS) on the timing of HI-induced cerebral tissue loss and gray matter injury, white matter injury and integrity, and the cerebral inflammatory response. On postnatal day 9, mice underwent HI by unilateral carotid artery occlusion followed by systemic hypoxia which resulted in early neuronal damage (MAP2 loss) at 3 h that did not increase up to day 15. LPS injection 14 h before HI (LPS+HI) significantly and gradually aggravated MAP2 loss from 3 h up to day 15, resulting in an acellular cystic lesion. LPS+HI increased white matter damage, reduced myelination in the corpus callosum and increased white matter fiber coherency in the cingulum. The number of oligodendrocytes throughout the lineage (Olig2-positive) was increased whereas more mature myelinating (CNPase-positive) oligodendrocytes were strongly decreased after LPS+HI. LPS+HI induced an increased and prolonged expression of cerebral cytokines/chemokines compared to HI. Additionally, LPS+HI increased macrophage/microglia activation and influx of neutrophils in the brain compared to HI. This study demonstrates the sensitizing effect of LPS on neonatal HI brain injury for an extended time-frame up to 15 days postinsult. LPS before HI induced a gradual increase in gray and white matter deficits, including reduced numbers of more mature myelinating oligodendrocytes and a decrease in white matter integrity. Moreover, LPS+HI prolonged and intensified the cerebral inflammatory response, including cellular infiltration. In conclusion, as the timing of damage and/or involved pathways are changed when HI is preceded by inflammation, experimental therapies might require modifications in the time window, dosage or combinations of therapies for efficacious neuroprotection.

Cerebral near infrared spectroscopy oximetry in extremely preterm infants: phase II randomised clinical trial

OBJECTIVE

To determine if it is possible to stabilise the cerebral oxygenation of extremely preterm infants monitored by cerebral near infrared spectroscopy (NIRS) oximetry.

DESIGN

Phase II randomised, single blinded, parallel clinical trial.

SETTING

Eight tertiary neonatal intensive care units in eight European countries.

PARTICIPANTS

166 extremely preterm infants born before 28 weeks of gestation: 86 were randomised to cerebral NIRS monitoring and 80 to blinded NIRS monitoring. The only exclusion criterion was a decision not to provide life support.

INTERVENTIONS

Monitoring of cerebral oxygenation using NIRS in combination with a dedicated treatment guideline during the first 72 hours of life (experimental) compared with blinded NIRS oxygenation monitoring with standard care (control).

MAIN OUTCOME MEASURES

The primary outcome measure was the time spent outside the target range of 55-85% for cerebral oxygenation multiplied by the mean absolute deviation, expressed in %hours (burden of hypoxia and hyperoxia). One hour with an oxygenation of 50% gives 5%hours of hypoxia. Secondary outcomes were all cause mortality at term equivalent age and a brain injury score assessed by cerebral ultrasonography.

RANDOMISATION

Allocation sequence 1:1 with block sizes 4 and 6 in random order concealed for the investigators. The allocation was stratified for gestational age (<26 weeks or ≥ 26 weeks).

BLINDING

Cerebral oxygenation measurements were blinded in the control group. All outcome assessors were blinded to group allocation.

RESULTS

The 86 infants randomised to the NIRS group had a median burden of hypoxia and hyperoxia of 36.1%hours (interquartile range 9.2-79.5%hours) compared with 81.3 (38.5-181.3) %hours in the control group, a reduction of 58% (95% confidence interval 35% to 73%, P<0.001). In the experimental group the median burden of hypoxia was 16.6 (interquartile range 5.4-68.1) %hours, compared with 53.6 (17.4-171.3) %hours in the control group (P=0.0012). The median burden of hyperoxia was similar between the groups: 1.2 (interquartile range 0.3-9.6) %hours in the experimental group compared with 1.1 (0.1-23.4) %hours in the control group (P=0.98). We found no statistically significant differences between the two groups at term corrected age. No severe adverse reactions were associated with the device.

CONCLUSIONS

Cerebral oxygenation was stabilised in extremely preterm infants using a dedicated treatment guideline in combination with cerebral NIRS monitoring.Trial registration ClinicalTrial.gov NCT01590316.

Brain-Sparing in Intrauterine Growth Restriction: Considerations for the Neonatologist

Intrauterine growth restriction (IUGR) is most commonly caused by placental insufficiency, in response to which the fetus adapts its circulation to preserve oxygen and nutrient supply to the brain ('brain-sparing'). Currently, little is known about the postnatal course and consequences of this antenatal adaptation of the cerebral circulation. The altered cerebral haemodynamics may persist after birth, which would imply a different approach with regard to cerebral monitoring and clinical management of IUGR preterm neonates than their appropriately grown peers. Few studies are available with regard to this topic, and the small body of evidence shows controversy. This review discusses the cerebral circulatory adaptations of IUGR fetuses and appraises the available literature on their postnatal cerebral circulation with potential clinical consequences.

Perfusion Index in Preterm Infants during the First 3 Days of Life: Reference Values and Relation with Clinical Variables

BACKGROUND

The perfusion index (PI) derived from pulse oximetry readings represents the ratio of pulsatile (arterial blood) and nonpulsatile contributors to infrared light absorption. PI has been shown to correlate with cardiac performance. In theory, PI is readily available on every pulse oximeter; therefore, no additional sensors or infant handling are required. Currently, reference values are lacking in (preterm) neonates and the association with common clinical conditions is unclear.

OBJECTIVES

To establish reference values for the PI in premature infants and at the same time determine the influence of common clinical conditions.

METHODS

PI was prospectively monitored on the lower limb for 72 h in 311 neonates born with a gestational age <32 weeks between January 2011 and December 2013. Longitudinal mixed-effects modeling was used. Linear, quadratic, and cubic models were explored. Main effects and interactions were investigated.

RESULTS

A squared model (0-24 h) followed by a linear model (24-72 h) provided the best fit of the data. PI was lowest around 12-18 h after birth and showed a steady increase thereafter. PI was positively related with female gender, gestational age, and pulse pressure. Negative associations were found with SIMV/HFOV ventilation, dopamine administration, mean arterial blood pressure, and arterial oxygen saturation. Although more complex, the general association with a patent ductus arteriosus was positive.

CONCLUSION

PI varied according to several clinical conditions. The association with common clinical factors suggests that PI might be used for monitoring neonatal hemodynamics and possibly as an additional guidance for interventions.

Neuroprotection by argon ventilation after perinatal asphyxia: a safety study in newborn piglets

Hypothermia is ineffective in 45% of neonates with hypoxic-ischemic encephalopathy. Xenon has additive neuroprotective properties, but is expensive, and its application complicated. Argon gas is cheaper, easier to apply, and also has neuroprotective properties in experimental settings. The aim was to explore the safety of argon ventilation in newborn piglets.

Methods

Eight newborn piglets (weight 1.4–3.0 kg) were used. Heart rate, blood pressure, regional cerebral saturation, and electrocortical brain activity were measured continuously. All experiments had a 30 min. baseline period, followed by three 60 min. periods of argon ventilation alternated with 30 min argon washout periods. Two animals were ventilated with increasing concentrations of argon (1h 30%, 1 h 50%, and 1 h 80%), two were subjected to 60 min. hypoxia (FiO₂ 0.08) before commencing 50% argon ventilation, and two animals received hypothermia following hypoxia as well as 50% argon ventilation. Two animals served as home cage controls and were terminated immediately.

Results

Argon ventilation did not result in a significant change of heart rate (mean ± s.d. −3.5±3.6 bpm), blood pressure (−0.60±1.11 mmHg), cerebral oxygen saturation (0.3±0.9%), electrocortical brain activity (−0.4±0.7 µV), or blood gas values. Argon ventilation resulted in elevated argon concentrations compared to the home cage controls (34.5, 25.4, and 22.4 vs. 7.3 µl/ml).

Conclusion

Ventilation with up to 80% argon during normoxia, and 50% argon after hypoxia did not affect heart rate, blood pressure, cerebral saturation and electrocortical brain activity. Clinical safety studies of argon ventilation in humans seem justified.

Arterial spin-labelling perfusion MRI and outcome in neonates with hypoxic-ischemic encephalopathy

PURPOSE

Hyperperfusion may be related to outcome in neonates with hypoxic-ischemic encephalopathy (HIE). The purpose of this study was to evaluate whether arterial spin labelling (ASL) perfusion is associated with outcome in neonates with HIE and to compare the predictive value of ASL MRI to known MRI predictive markers.

METHODS

Twenty-eight neonates diagnosed with HIE and assessed with MR imaging (conventional MRI, diffusion-weighted MRI, MR spectroscopy [MRS], and ASL MRI) were included. Perfusion in the basal ganglia and thalami was measured. Outcome at 9 or 18 months of age was scored as either adverse (death or cerebral palsy) or favourable.

RESULTS

The median (range) perfusion in the basal ganglia and thalami (BGT) was 63 (28-108) ml/100 g/min in the neonates with adverse outcome and 28 (12-51) ml/100 g/min in the infants with favourable outcome (p < 0.01). The area-under-the-curve was 0.92 for ASL MRI, 0.97 for MRI score, 0.96 for Lac/NAA and 0.92 for ADC in the BGT. The combination of Lac/NAA and ASL MRI results was the best predictor of outcome (r(2) = 0.86, p < 0.001).

CONCLUSION

Higher ASL perfusion values in neonates with HIE are associated with a worse neurodevelopmental outcome. A combination of the MRS and ASL MRI information is the best predictor of outcome.

KEY POINTS

• Arterial spin labelling MRI can predict outcome in neonates with hypoxic-ischemic encephalopathy • Basal ganglia and thalami perfusion is higher in neonates with adverse outcome • Arterial spin labelling complements known MRI parameters in the prediction of outcome • The combined information of ASL and MRS measurements is the best predictor of outcome.

Hypotension in preterm neonates: low blood pressure alone does not affect neurodevelopmental outcome

OBJECTIVE

To compare neurodevelopmental outcome, mean arterial blood pressure (MABP), and regional cerebral oxygenation (rSco2) between preterm neonates treated for hypotension and controls.

STUDY DESIGN

Preterm neonates (N = 66) with a gestational age (GA) ≤32 weeks, without a patent ductus arteriosus, treated for hypotension (dopamine ≥5 μg/kg/min) were included. Neonates were matched to controls for GA, birth weight, sex, and year of birth. The rSco2 was determined by using near-infrared spectroscopy. Monitoring of MABP, rSco2, and arterial saturation was started at admission and continued for at least 72 hours. Neurodevelopmental outcome was assessed at 18 and 24 months' corrected age by using the Griffiths Mental Development Scales or the Bayley Scales of Infant and Toddler Development, Third Edition.

RESULTS

Infants treated for hypotension spent more time with an MABP less than GA (median 9% vs 0%, P < .001) and time with an MABP/rSco2 correlation >0.5 (27% vs 17%, P < .001). Time spent with an rSco2 <50% and neurodevelopmental outcome at 18 and 24 months' corrected age were not significantly different between infants treated for hypotension and controls. The 26 neonates with an rSco2 <50% for >10% of time had a lower neurodevelopmental outcome at 18 months (median 99 vs 104, P = .02).

CONCLUSION

An MABP less than GA (in weeks) was not associated with lower rSco2 or with lower neurodevelopmental outcome scores. However, regardless of MABP, low rSco2 was associated with lower neurodevelopmental outcome scores. Perfusion/oxygenation variables could be of additional value in neonatal intensive care.

Feasibility and safety of erythropoietin for neuroprotection after perinatal arterial ischemic stroke

OBJECTIVE

To perform a feasibility and safety study with recombinant human erythropoietin (rhEPO) in neonates with perinatal arterial ischemic stroke.

STUDY DESIGN

Neonates with a magnetic resonance imaging-confirmed perinatal arterial ischemic stroke (n = 21) were treated with 1000 IU/kg rhEPO immediately after diagnosis and at 24 and 48 hours after the first dose. Repeat magnetic resonance imaging was performed when the patients were 3 months of age. Coagulation and hematologic variables (red blood cells, white blood cells, platelet counts) were performed in the first week after initiation of treatment. We also compared 10 patients who were treated with rhEPO with 10 historic infants with perinatal arterial ischemic stroke matched for the involved arterial branch to investigate whether rhEPO reduces the residual size of the infarction and subsequent brain growth between first and second scan.

RESULTS

Seizures were a first symptom in 20 of 21 neonates. Heart rate, blood pressure, and coagulation function were in the normal range, as were red blood cells, white blood cells, and platelet counts. In a subgroup of 10 rhEPO-treated neonates, no differences were detected in residual infarction volumes or neurodevelopmental outcome compared with their historical nontreated counterparts.

CONCLUSIONS

rhEPO in neonates with perinatal arterial ischemic stroke had no adverse effects on red blood cells, white blood cells, platelets counts, or coagulation. rhEPO, 3000 IU/kg in total, given during a 3-day period, appears to be a safe therapy. The beneficial effects remains to be demonstrated in a larger, randomized, double-blind, placebo-controlled trial.

Early end-tidal carbon monoxide levels, patency of the ductus arteriosus and regional cerebral oxygenation in preterm infants

BACKGROUND

Carbon monoxide (CO), a relaxant regulator of muscle tone and marker of oxidative stress and inflammation, can be measured in exhaled air by determination of end-tidal CO corrected for CO in ambient air (ETCOc).

OBJECTIVE

Increased endogenous production of CO may influence patency of the ductus arteriosus, cerebral perfusion and, subsequently, cerebral oxygenation. The aim was to study the relation between early ETCOc levels, hemodynamically significant patent ductus arteriosus (hsPDA) and cerebral oxygenation (rScO2) in preterm infants <32 weeks' gestational age and determine predictive values of ETCOc for hsPDA.

METHODS

ETCOc was measured in 91 infants within the first 24 h after birth. A hsPDA was diagnosed according to echocardiographic indices. In 78/91 infants, rScO2 was monitored with near-infrared spectroscopy to assess cerebral oxygenation.

RESULTS

ETCOc values were significantly higher in infants who subsequently developed hsPDA (2.3 ± 0.7 ppm) vs. no-hsPDA (1.7 ± 0.6 ppm), p < 0.001. With a cut-off value of 2.5 ppm, positive and negative predictive values of ETCOc for hsPDA were 55 and 88%, respectively. rScO2 values were not different between the two groups (64 ± 1 vs. 65 ± 3%, NS).

CONCLUSIONS

The higher ETCOc values in hsPDA infants early after birth reflect the early relaxant state of ductal muscular tone. ETCOc <2.5 ppm within 24 h after birth may predict the subsequent absence of hsPDA. ETCOc showed no correlation with cerebral oxygenation in both groups.

Early detection of prenatal cardiocirculatory compromise in small for gestational age infants

BACKGROUND

Impairment of gas and substrate exchange through the placenta leads to fetal hypoxia and growth restriction. Oxygenation of vital organs is maintained with preferential perfusion at the expense of less vital organs, challenging the fetal cardiovascular system.

OBJECTIVES

To identify cardiovascular compromise in preterm small for gestational age (SGA) infants using the cardiac biomarker B-type natriuretic peptide (BNP), which indicates the workload of the myocardium.

METHODS

In this retrospective case-control study, 26 SGA infants born at less than 32 weeks of gestation from October 2009 to October 2010 were matched for gestational age and month of birth with 26 appropriate for gestational age (AGA) infants. Antenatal Doppler ultrasound was used to identify fetal hemodynamic changes by determination of the pulsatility index (PI) of the middle cerebral artery (MCA-PI), umbilical artery (UA-PI) and veins of the ductus venosus (DV-PIV). These indices were compared with BNP levels obtained within 6 h after birth.

RESULTS

Antenatal PIs of MCA, UA and DV were significantly related to elevated BNP levels after birth in SGA infants, but not in AGA infants (SGA: MCA-PI = r(2) 0.23, p < 0.05; UA-PI = r(2) 0.46, p < 0.01; DV-PIV = r(2) 0.31, p < 0.05). Furthermore, signs of perinatal (chronic) asphyxia coincided with elevated levels of BNP. SGA was related to more postnatal cardiocirculatory complications. No significant relations between postnatal cardiac ultrasound measurements, placenta size and BNP were found.

CONCLUSION

BNP levels were elevated early after birth in SGA infants and corresponded positively with Doppler indices of circulatory compromise. This suggests an increased workload of the myocardium.

Feeding issues in IUGR preterm infants

Intra-uterine growth restriction (IUGR) is a severe and quite common problem in obstetrics. A condition of placental dysfunction can lead to a cardiovascular adaptation in the fetus characterized by a redistribution of cardiac output to maintain oxygen supply to the heart, adrenal glands and brain - the so-called brain sparing effect - at the expense of visceral organs (such as the gastrointestinal system). This condition may predispose IUGR infants to impaired gut function after birth. A higher incidence of necrotizing enterocolitis (NEC) is documented in IUGR preterm infants. Therefore, a common practice in neonatal intensive care units is to delay feeds to reduce the risk of feeding intolerance. Recent trials, however, have shown that early enteral feeding in IUGR infants is safe and it would appear, on the basis of the few available data, that breast milk could offer protection against NEC. This mini-review offers an update on feeding in IUGR infants. Future perspectives on the usefulness of Doppler and regional splanchnic and cerebral saturation monitoring for deciding when to start feeding are also provided.

Hydrocortisone treatment for bronchopulmonary dysplasia and brain volumes in preterm infants

OBJECTIVE

To assess whether there was an adverse effect on brain growth after hydrocortisone (HC) treatment for bronchopulmonary dysplasia (BPD) in a large cohort of infants without dexamethasone exposure.

STUDY DESIGN

Infants who received HC for BPD between 2005 and 2011 and underwent magnetic resonance imaging at term-equivalent age were included. Control infants born in Geneva (2005-2006) and Utrecht (2007-2011) were matched to the infants treated with HC according to segmentation method, sex, and gestational age. Infants with overt parenchymal pathology were excluded. Multivariable analysis was used to determine if there was a difference in brain volumes between the 2 groups.

RESULTS

Seventy-three infants treated with HC and 73 matched controls were included. Mean gestational age was 26.7 weeks, and mean birth weight was 906 g. After correction for gestational age, postmenstrual age at time of scanning, the presence of intraventricular hemorrhage, and birth weight z-score, no differences were found between infants treated with HC and controls in total brain tissue or cerebellar volumes.

CONCLUSIONS

In the absence of associated parenchymal brain injury, no reduction in brain tissue or cerebellar volumes could be found at term-equivalent age between infants with or without treatment with HC for BPD.

Tocolytic indomethacin: effects on neonatal haemodynamics and cerebral autoregulation in the preterm newborn

BACKGROUND

Indomethacin has vasoactive properties in cerebral and systemic vascular beds, and it improves cerebral autoregulatory ability. We speculated that tocolytic indomethacin will improve cerebral autoregulatory ability in the very preterm infant in early postnatal life.

METHODS

Eighteen stable preterm infants gestational age (GA) 25.3-29.6 weeks, birth weight (BW) 660-1430 grams), whose mothers had received 50-150 mg of tocolytic indomethacin within 24 h before birth, and 18 individually matched controls (GA 25.0-29.7 weeks, BW 700-1390 grams) were studied four times for 15 min in the first 24 h of life. Autoregulation was assessed by determining correlations between mean arterial blood pressure (MABP (mm Hg)) and near-infrared spectroscopy-monitored cerebral oxygenation (rScO2).

RESULTS

MABPs were significantly higher in the indomethacin infants than in the control infants (p=0.03). A decreased ability to autoregulate was found in four of the indomethacin infants, and in six of the control infants, which is not significantly different.

CONCLUSIONS

Prenatally administered indomethacin, given as a tocolytic in doses of 50-150 mg per day, improved transitional circulation in very preterm infants by significantly raising the MABP. It did not have an effect on the ability to autoregulate the cerebral circulation. In this study, no differences in short-term outcomes, like haemorrhagic or ischaemic cerebral lesions, were observed.

Evaluation of perinatal arterial ischemic stroke using noninvasive arterial spin labeling perfusion MRI

BACKGROUND

Arterial spin labeling (ASL) magnetic resonance imaging (MRI) can evaluate brain perfusion in neonates noninvasively. The aim of this study was to investigate whether ASL MRI can demonstrate perfusion abnormalities in neonates diagnosed with perinatal arterial ischemic stroke (PAIS).

METHODS

Pulsed ASL perfusion MR images were acquired in the subacute stage (5-6 d after birth) and at follow-up (13 d to 16 wk after birth) in four PAIS patients. Images were visually evaluated for hypo- and hyperperfusion. In addition, cerebral oxygenation was monitored using near infrared spectroscopy (NIRS).

RESULTS

In three PAIS patients, ASL images showed hypoperfusion in the stroke area. In one of these, hyperperfusion was visualized in the periphery of the stroke area. In one PAIS patient, hyperperfusion was seen in the stroke area. In all infants, cerebral oxygenation was higher in the infarcted hemisphere as compared with the contralateral hemisphere. Follow-up ASL images showed partial recovery of perfusion in the stroke area.

CONCLUSION

ASL perfusion MRI is able to reliably detect hypo- and hyperperfusion in PAIS patients and can be used to monitor the evolution of perfusion after an ischemic event.

Early life intervention with glucocorticoids has negative effects on motor development and neuropsychological function in 14-17 year-old adolescents

OBJECTIVE

To reduce the risk of bronchopulmonary dysplasia, preterm infants receive neonatal treatment with glucocorticoids, mostly dexamethasone (DEX). Compared to current protocols, treatment regimens of the late 1980s - early 1990s prescribed high doses of DEX for an extensive period up to 6 weeks. Worldwide at least one million children have been treated with this dose regimen. Previous studies have shown adverse effects of neonatal treatment with the glucocorticoid dexamethasone (DEX) on outcome in children aged 7-10 years. On the other hand, treatment with another glucocorticoid, hydrocortisone (HC), was not related to adverse effects in childhood. In the current study we determined the consequences of early life intervention with DEX or HC in adolescents (age 14-17 years). Besides motor function and intellectual capacities, we also examined fundamental neuropsychological functions which have so far received little attention.

METHODS

In an observational cohort study we compared 14-17 year-old adolescents who received DEX (.5 mg/kg/day tapering off to .1 mg/kg/day over 21 days, n=63), or HC (5 mg/kg/day tapering off to 1 mg/kg/day over 22 days, n=67), or did not receive neonatal glucocorticoids (untreated, n=71) after premature birth (gestational age<32 weeks). Because gestational age was shorter and duration of ventilation was longer in the DEX-treated group, all analyses were corrected for these potential confounders. Motor function, IQ, and neuropsychological functions were assessed.

RESULTS

DEX-treated group participants scored lower on gross motor skill tasks than their HC-treated and untreated counterparts. A higher proportion of DEX-treated girls needed special education compared to the other groups. DEX-treated adolescents performed poorer on neuropsychological tasks measuring alertness, visuomotor coordination, and emotion recognition. The HC-treated group did not differ from the untreated group.

CONCLUSIONS

Even after 14-17 years, neonatal treatment with .5 mg/kg/day DEX was associated with adverse effects on motor function, school level, and neuropsychological functions, whereas treatment with the clinically equally effective dose of 5 mg/kg/day HC was not. Potential physiological mechanisms underlying the differences in dexamethasone and hydrocortisone effects are discussed. Based on the current findings, we recommend early identification of neuropsychological deficits after DEX treatment in order to specify extra educational needs.

Antenatal allopurinol reduces hippocampal brain damage after acute birth asphyxia in late gestation fetal sheep

Free radical-induced reperfusion injury is a recognized cause of brain damage in the newborn after birth asphyxia. The xanthine oxidase inhibitor allopurinol reduces free radical synthesis and crosses the placenta easily. Therefore, allopurinol is a promising therapeutic candidate. This study tested the hypothesis that maternal treatment with allopurinol during fetal asphyxia limits ischemia-reperfusion (I/R) damage to the fetal brain in ovine pregnancy. The I/R challenge was induced by 5 repeated measured compressions of the umbilical cord, each lasting 10 minutes, in chronically instrumented fetal sheep at 0.8 of gestation. Relative to control fetal brains, the I/R challenge induced significant neuronal damage in the fetal hippocampal cornu ammonis zones 3 and 4. Maternal treatment with allopurinol during the I/R challenge restored the fetal neuronal damage toward control scores. Maternal treatment with allopurinol offers potential neuroprotection to the fetal brain in the clinical management of perinatal asphyxia.

A phase II randomized clinical trial on cerebral near-infrared spectroscopy plus a treatment guideline versus treatment as usual for extremely preterm infants during the first three days of life (SafeBoosC): study protocol for a randomized controlled trial

Background

Every year in Europe about 25,000 infants are born extremely preterm. These infants have a 20% mortality rate, and 25% of survivors have severe long-term cerebral impairment. Preventative measures are key to reduce mortality and morbidity in an extremely preterm population. The primary objective of the SafeBoosC phase II trial is to examine if it is possible to stabilize the cerebral oxygenation of extremely preterm infants during the first 72 hours of life through the application of cerebral near-infrared spectroscopy (NIRS) oximetry and implementation of an clinical treatment guideline based on intervention thresholds of cerebral regional tissue saturation rStO₂.

Methods/Design

SafeBoosC is a randomized, blinded, multinational, phase II clinical trial. The inclusion criteria are: neonates born more than 12 weeks preterm; decision to conduct full life support; parental informed consent; and possibility to place the cerebral NIRS oximeter within 3 hours after birth. The infants will be randomized into one of two groups. Both groups will have a cerebral oximeter monitoring device placed within three hours of birth. In the experimental group, the cerebral oxygenation reading will supplement the standard treatment using a predefined treatment guideline. In the control group, the cerebral oxygenation reading will not be visible and the infant will be treated according to the local standards. The primary outcome is the multiplication of the duration and magnitude of rStO₂ values outside the target ranges of 55% to 85%, that is, the ‘burden of hypoxia and hyperoxia’ expressed in ‘%hours’. To detect a 50% difference between the experimental and control group in %hours, 166 infants in total must be randomized. Secondary outcomes are mortality at term date, cerebral ultrasound score, and interburst intervals on an amplitude-integrated electroencephalogram at 64 hours of life and explorative outcomes include neurodevelopmental outcome at 2 years corrected age, magnetic resonance imaging at term, blood biomarkers at 6 and 64 hours after birth, and adverse events.

Discussion

Cerebral oximetry guided interventions have the potential to improve neurodevelopmental outcome in extremely preterm infants. It is a logical first step to test if it is possible to reduce the burden of hypoxia and hyperoxia.

Trial registration

ClinicalTrial.gov, NCT01590316

Cerebral oxygenation, extraction, and autoregulation in very preterm infants who develop peri-intraventricular hemorrhage

OBJECTIVE

To test the hypothesis that near-infrared spectroscopy (NIRS)-determined patterns of regional cerebral oxygen saturation (rScO2), cerebral fractional tissue oxygen extraction (cFTOE), and autoregulatory ability can identify neonates at risk for developing peri-intraventricular hemorrhage (PIVH).

STUDY DESIGN

This case-control study is a subanalysis of 30 neonates who developed PIVH >12 hours after admission as part of a lager prospective observational cohort study comprising 650 preterm neonates born at ≤32 weeks' gestational age. PIVH was diagnosed by cranial ultrasound, performed at least once daily. Mean arterial blood pressure (MABP), NIRS-determined rScO2, cFTOE, and MABP-rScO2 correlation were monitored from birth to 72 hours of age.

RESULTS

Infants with PIVH received more inotropic drugs before being diagnosed with PIVH. Significantly more infants with severe PIVH needed treatment for patent ductus arteriosus. The MABP-rScO2 correlation was >0.5 significantly more often before mild/moderate PIVH and after severe PIVH compared with controls. rScO2 was higher and cFTOE lower in infants before severe PIVH.

CONCLUSION

NIRS-monitored rScO2 and cFTOE suggest cerebral hyperperfusion in infants with severe PIVH. Moreover, MABP-rScO2 correlation indicates more blood pressure-passive brain perfusion in infants with PIVH. Continuous assessment of patterns of cerebral oxygenation and arterial blood pressure may identify those preterm infants at risk for severe PIVH and prompt consideration of preventive measures.