Early detection of neurologic injury and issues of rehabilitation after pediatric cardiac extracorporeal membrane oxygenation

The Ca2+-Binding S100B Protein: An Important Diagnostic and Prognostic Neurobiomarker in Pediatric Laboratory Medicine

In recent decades a significant scientific effort has focused on projects regarding the use of neurobiomarkers in perinatal medicine with a view to understanding the mechanisms that interfere with physiological patterns of brain development and lead to ominous effects in several human diseases. Numerous potential neurobiomarkers have been proposed for use in monitoring high-risk fetuses and newborns, including markers of oxidative stress, neuroproteins, and vasoactive agents. Nonetheless, the use of these markers in clinical practice remains a matter of debate. Recently, the calcium-binding S100B protein has been proposed as being an ideal neurobiomarker, thanks to its simple availability and easy reproducibility, to the possibility of detecting it noninvasively in biological fluids with good reproducibility, and to the possibility of a longitudinal evaluation in relation to reference curves. The present chapter contains an overview of the most significant studies on the assessment of S100B in different biological fluids as a trophic factor and/or marker of brain damage in high-risk fetuses and newborns.

Use of early biomarkers in neonatal brain damage and sepsis: state of the art and future perspectives

The identification of early noninvasive biochemical markers of disease is a crucial issue of the current scientific research, particularly during the first period of life, since it could provide useful and precocious diagnostic information when clinical and radiological signs are still silent. The ideal biomarker should be practical and sensitive in the precocious identification of at risk patients. An earlier diagnosis may lead to a larger therapeutic window and improve neonatal outcome. Brain damage and sepsis are common causes of severe morbidity with poor outcome and mortality during the perinatal period. A large number of potential biomarkers, including neuroproteins, calcium binding proteins, enzymes, oxidative stress markers, vasoactive agents, and inflammatory mediators, have been so far investigated. The aim of the present review was to provide a brief overview of some of the more commonly investigated biomarkers used in case of neonatal brain damage and sepsis.

Perioperative mechanical circulatory support in children with critical heart disease

OPINION STATEMENT

The treatment of cardiovascular failure in the perioperative period with the use of mechanical circulatory support is a well-recognized, well-developed, and commonly utilized treatment modality. Regardless of the exact circumstances of initiation, the use of a support device is a "bridge." Where there has been an acute myocardial insult, short-term assist devices can serve as a "bridge to immediate survival," a "bridge to recovery," or even a "bridge to the next decision." Mechanical circulatory support can serve as a treatment of cardiovascular decompensation caused by myocarditis, acute myocardial insult, low cardiac output following surgery, and congenital heart disease. The utilization of such support carries significant risks such as bleeding, infection, and thrombosis. However, these can be minimized in order to allow for the safe and effective deployment of this therapeutic strategy. One specific therapeutic domain in which these devices provide immediate impact is during cardiac arrest. Although outcomes of cardiac arrest remain poor, use of a mechanical device as an intervention has allowed salvage of otherwise certain mortality. However, it is important to note that the utility of support was most pronounced in patients that were not on either extreme of the survival prediction curve. This can be best summarized by the concept of "not too early, not too late." Therefore, it is the responsibility of the entire care team to find the appropriate patient population in which to "pull the trigger" on mechanical support as a therapy. This decision point is supported by a monitoring strategy that can be utilized to predict deterioration and intervene adequately. Most importantly, an effective monitoring strategy allows the practitioner to judge the effectiveness of treatment and support strategies and make adjustments in a timely manner, potentially with mechanical support in the perioperative period.

New markers of neonatal neurology

Hypoxia-ischemia (H-I) constitutes the main phenomenon responsible for brain-blood barrier permeability modifications leading to cerebral vascular auto-regulation loss in newborns. Hypotension, cerebral ischemia, and reperfusion are the main events involved in vascular auto-regulation loss leading to cell death and tissue damage. Reperfusion could be critical since organ damage, particularly of the brain, may be amplified during this period. An exaggerated activation of vasoactive agents, of calcium mediated effects could be responsible for reperfusion injury (R-I), which, in turns, leads to cerebral hemorrhage and damage. These phenomena represent a common repertoire in newborns complicated by perinatal acute or chronic hypoxia treated by risky procedures such as mechanical ventilation, nitric oxide supplementation, brain cooling, and extracorporeal membrane oxygenation (ECMO). Despite accurate monitoring, the post-insult period is crucial, as clinical symptoms and standard monitoring parameters may be silent at a time when brain damage is already occurring and the therapeutic window for pharmacological intervention is limited. Therefore, the measurement of circulating biochemical markers of brain damage, such as vasoactive agents and nervous tissue peptides is eagerly awaited in clinical practice to detect high risk newborns. The present review is aimed at investigating the role of biochemical markers such as adrenomedullin, a vasoactive peptide; S100B, a calcium binding protein, activin A, a glycoprotein, in the cascade of events leading to I-R injury in newborns complicated by perinatal asphyxia.

Two-year survival, mental, and motor outcomes after cardiac extracorporeal life support at less than five years of age

OBJECTIVE

Comprehensive outcome assessment of children receiving cardiac extracorporeal life support.

METHODS

From 2000 to 2004, 39 consecutive children (aged 1 day to 4.4 years) had cardiac extracorporeal life support. Neurodevelopmental follow-up of all survivors was performed more than 6 months after life support (aged 53 +/- 12 months). Developmental delay was defined as a score of less than 70 on the Bayley Scales of Infant Development II or Wechsler Preschool and Primary Scale of Intelligence. Predictor variables for mortality (at 2 years' follow-up) and delay were examined by univariate and multivariate analyses.

RESULTS

Indications for extracorporeal life support were progressive low cardiac output in 14 (36%), failed weaning from cardiopulmonary bypass in 13 (33%), cardiac arrest in 9 (23%), and hypoxia in 3 (8%). Cardiac anatomy was single ventricle in 16 (41%), biventricular in 21 (54%), and myocarditis in 2 (5%). Survival was 18 (46%) at hospital discharge and 16 (41%) at 2 years. In survivors, mental score was 73 +/- 16 (normal 100 +/- 15), and 8 (50%) had mental delay. Initiating extracorporeal life support during cardiopulmonary resuscitation and duration of this resuscitation were not associated with death or mental delay. On multivariable Cox regression, lactate on admission to the pediatric intensive care unit (hazard rate 1.13; 95% confidence intervals 1.08-1.27) and single ventricle anatomy (hazard rate 3.93; 95% confidence intervals 1.62-9.49) were associated with death at 2 years. Stepwise multiple regression found time for lactate to normalize on extracorporeal life support, highest inotrope score during 120 hours of life support, and chromosomal abnormality explained 76.7% of the variance in mental score.

CONCLUSION

Cardiac extracorporeal life support had a 41% 2-year survival. Potentially modifiable variables (time for lactate to normalize and highest inotrope score early during extracorporeal life support) explained 69% of mental score variance.

S100B protein in biological fluids: a tool for perinatal medicine

The diagnosis of perinatal insults currently relies on adequate documentation of general medical and obstetric factors and on radiologic and laboratory assessments. The measurement of brain constituents such as S100B protein may offer an alternative and direct indicator of cell damage in the nervous system when clinical and radiologic assessments are still silent and has the additional advantage of providing a quantitative indicator of the extent of brain lesions. S100B protein has been measured by several immunoassays in biological fluids (i.e., cerebrospinal fluid, blood, amniotic fluid, and urine) from fetuses and newborns at high risk of perinatal brain damage. S100B protein in biological fluids increased at an early stage when standard monitoring procedures were still silent in the study populations that later developed brain damage. S100B concentration was also significantly correlated with the extent of brain lesions. S100B protein appears to satisfy the criteria for a marker for brain injuries in perinatal medicine: (a) simple to perform measurements with good reproducibility; (b) detection in a variety of biological fluids, possibly reducing perinatal stress related to testing; (c) possible use in longitudinal monitoring because of its 1-h half-life; and (d) well-established use as an early and quantitative marker of brain lesions/damage. Finally, because of the neurotrophic role putatively played by S100B, its measurement in biological fluids at pre-/perinatal ages makes it a candidate for the laboratory evaluation of brain maturation.

Neonatal and pediatric extracorporeal membrane oxygenation using nonocclusive blood pumps: the Vienna experience

Neonatal and pediatric extracorporeal membrane oxygenation (ECMO) is carried out commonly using occlusive blood pumps. Centrifugal pumps provide simple and safe technology for transportation on ECMO. The assistence respiratoire extra corporelle (AREC) system enables single needle venovenous ECMO for infants. We report on our experience with neonatal and pediatric ECMO treatments using nonocclusive blood pumps. One-hundred forty-six ECMO treatments were performed for cardiac, neonatal, and pediatric indications in 54, 19, and 27% of cases. Centrifugal pumps were used in 99, and the AREC system in 42 cases. Hospital mortality was estimated retrospectively and influence of type of pump, type of ECMO belonging to indication group, and lactate at ECMO installation were estimated. Irreversible organ failure leading to ECMO termination was investigated within groups of indications. Survival (recent 50 ECMO treatments) was 80, 70, 43, and 30% after meconium aspiration syndrome, acute respiratory distress syndrome, cardiac surgery, and prolonged resuscitation. Lactate exceeding 100 mg/dl at ECMO installation predicted significantly worse outcome. Cerebral damage was the main reason for ECMO termination in all but persistent circulatory failure in the cardiac group. Myocardial recovery resulted in all except 2 cardiac cases. Nonocclusive blood pumps can be used safely in neonatal and pediatric ECMO. Early installation may improve outcome markedly. In cardiac cases results of surgery should be thoroughly investigated on the table before ECMO installation to prevent hopeless ECMO treatments.