Electroencephalographic, neuroradiologic, and neurodevelopmental studies in infants with subclavian steal during ECMO

A Systematic Review of Clinical Outcomes After Carotid Artery Ligation Versus Carotid Artery Reconstruction Following Venoarterial Extracorporeal Membrane Oxygenation in Infants and Children

INTRODUCTION

In pediatric and neonatal populations, the carotid artery is commonly cannulated for venoarterial (VA) extracorporeal membrane oxygenation (ECMO). The decision to ligate (carotid artery ligation [CAL]) versus reconstruct (carotid artery reconstruction [CAR]) the artery at decannulation remains controversial as long-term neurologic outcomes remain unknown. The objective of this study was to summarize current literature on clinical outcomes following CAL and CAR after Venoarterial Extracorporeal Membrane Oxygenation (VA-ECMO).

METHODS

PubMed (MEDLINE), Embase, Web of Science, and Cochrane databases were searched using keywords from January 1950 to October 2020. Studies examining clinical outcomes following CAL and CAR for VA-ECMO in patients <18 y of age were included. Prospective and retrospective cohort studies, case series, case-control studies, and case reports were included. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were performed independently by two reviewers. Assessment of risk of bias was performed.

RESULTS

Eighty studies were included and classified into four categories: noncomparative clinical outcomes after CAL (n = 23, 28.8%), noncomparative clinical outcomes after CAR (n = 12, 15.0%), comparative clinical outcomes after CAL and/or CAR (n = 28, 35.0%), and case reports of clinical outcomes after CAL and/or CAR (n = 17, 21.3%). Follow-up ranged from 0 to 11 y. CAR patency rates ranged from 44 to 100%. There was no substantial evidence supporting an association between CAL versus CAR and short-term neurologic outcomes.

CONCLUSIONS

Studies evaluating outcomes after CAL versus CAR for VA-ECMO are heterogeneous with limited generalizability. Further studies are needed to evaluate long-term consequences of CAL versus CAR, especially as the first survivors of pediatric/neonatal ECMO approach an age of increased risk of carotid stenosis and stroke.

Neurological Monitoring and Complications of Pediatric Extracorporeal Membrane Oxygenation Support

Extracorporeal membrane oxygenation is extracorporeal life support for life-threatening cardiopulmonary failure. Since its introduction, the use of extracorporeal membrane oxygenation has expanded to patients with more complex comorbidities without change in patient mortality rates. Although many patients survive, significant neurological complications like seizures, ischemic strokes, and intracranial hemorrhage can occur during extracorporeal membrane oxygenation care. The risks of these complications often add to the complexity of decision-making surrounding extracorporeal membrane oxygenation support. In this review, we discuss the pathophysiology and incidence of neurological complications in children supported on extracorporeal membrane oxygenation, factors influencing the incidence of these complications, commonly used neurological monitoring modalities, and outcomes for this complex patient population. We discuss the current literature on the use of electroencephalography for both seizure detection and monitoring of background electroencephalographic changes, in addition to the use of less commonly used imaging modalities like transcranial Doppler. We summarize the knowledge gaps and the lack of clinical consensus guidelines for managing these potentially life-changing neurological complications. Finally, we discuss future work to further understand the pathophysiology of extracorporeal membrane oxygenation-related neurological complications.

The 1-Year Follow-Up Clinic for Neonates and Children After Respiratory Extracorporeal Membrane Oxygenation Support: A 10-Year Single Institution Experience

OBJECTIVES

To establish the effectiveness of a "1-year extracorporeal membrane oxygenation follow-up clinic" and to characterize any neurodevelopmental concerns identified.

DESIGN

Single-center retrospective cohort of respiratory extracorporeal membrane oxygenation survivors over 10 years.

SETTING

Nationally commissioned center for neonatal and pediatric (> 28 d of life) respiratory extracorporeal membrane oxygenation.

PATIENTS

Children attending the follow-up clinic 1 year after receiving respiratory extracorporeal membrane oxygenation between 2003 and 2013.

INTERVENTIONS

Standardized follow-up 1 year after extracorporeal membrane oxygenation.

MEASUREMENTS AND MAIN RESULTS

In 10 years, 290 children received extracorporeal membrane oxygenation, 194 (67%) survived; all were offered 1-year follow-up, and 98 (51%) attended the clinic. Among these, 51 of 98 (52%) had meconium aspiration syndrome, and 74 of 98 (75%) were on veno-arterial extracorporeal membrane oxygenation with a median (interquartile range) duration of 6 days (4-8 d). Neurodevelopmental problems were identified in 30 of 98 (30%). The specific abnormalities noted included neurologic (seizures, motor, or vision abnormalities) (n = 8), hearing with/without language delay (n = 8), and behavioral problems (as reported by parents) (n = 6), with eight of 30 (27%) having difficulties spanning these domains. An acute neurologic event on extracorporeal membrane oxygenation was found to be the only risk factor for neurodevelopmental concerns (p = 0.006 with odds ratio 5.4 [95% CI, 1.63-17.92]). Despite having neither a cardiac arrest nor an acute neurologic event documented, 18 of 74 (24.3%), 95% CI (15.1-35.7), had neurodevelopmental concerns at 1-year follow-up. Among the nonattenders, 30 (15%) had local follow-up, and 66 (34%) were lost to follow-up.

CONCLUSIONS

All extracorporeal membrane oxygenation survivors need follow-up either at the extracorporeal membrane oxygenation center or in their community, as evidenced by the 1-year follow-up data. Our 1-year extracorporeal membrane oxygenation follow-up clinic provides an opportunity to engage with families, identify neurodevelopmental concerns, and signpost to appropriate services. Of concern, one third of survivors are lost to follow-up, some with an acute neurologic event on extracorporeal membrane oxygenation, a significant risk factor. A consensus-based standardized national follow-up program is vital.

Hypoxic regulation of the fetal cerebral circulation

Fetal cerebrovascular responses to acute hypoxia are fundamentally different from those observed in the adult cerebral circulation. The magnitude of hypoxic vasodilatation in the fetal brain increases with postnatal age although fetal cerebrovascular responses to acute hypoxia can be complicated by age-dependent depressions of blood pressure and ventilation. Acute hypoxia promotes adenosine release, which depresses fetal cerebral oxygen consumption through action of adenosine on neuronal A1 receptors and vasodilatation through activation of A2 receptors on cerebral arteries. The vascular effect of adenosine can account for approximately half the vasodilatation observed in response to hypoxia. Hypoxia-induced release of nitric oxide and opioids can account for much of the adenosine-independent cerebral vasodilatation observed in response to hypoxia in the fetus. Direct effects of hypoxia on cerebral arteries account for the remaining fraction, although the vascular endothelium contributes relatively little to hypoxic vasodilatation in the immature cerebral circulation. In contrast to acute hypoxia, fetal cerebral blood flow tends to normalize during acclimatization to chronic hypoxia even though cardiac output is depressed. However, uncompensated chronic hypoxia in the fetus can produce significant changes in brain structure and function, alteration of respiratory drive and fluid balance, and increased incidence of intracranial hemorrhage and periventricular leukomalacia. At the level of the fetal cerebral arteries, chronic hypoxia increases protein content and depresses norepinephrine release, contractility, and receptor densities associated with contraction but also attenuates endothelial vasodilator capacity and decreases the ability of ATP-sensitive and calcium-sensitive potassium channels to promote vasorelaxation. Overall, fetal cerebrovascular adaptations to chronic hypoxia appear prioritized to conserve energy while preserving basic contractility. Many gaps remain in our understanding of how the effects of acute and chronic hypoxia are mediated in fetal cerebral arteries, but studies of adult cerebral arteries have produced many powerful pharmacological and molecular tools that are simply awaiting application in studies of fetal cerebral artery responses to hypoxia.

Low superior vena cava flow and neurodevelopment at 3 years in very preterm infants

OBJECTIVES

Low superior vena cava (SVC) flow is common in the first hours after very preterm birth and has a strong association with subsequent periventricular/intraventricular hemorrhage. We report the neurodevelopmental outcome at 3 years of age of very preterm babies who had serial echocardiographic studies, including measures of SVC flow, during the first 48 hours after birth.

STUDY DESIGN

A prospective observational study was performed on a cohort of 126 babies (<30 weeks), 103 of whom survived to discharge. Neurodevelopmental follow-up data, which included abnormal developmental quotient, abnormal motor score, and cerebral palsy, were available for 93% of this cohort at 3 years of age. Relations between 3-year outcome and early hemodynamic measures and clinical parameters were explored.

RESULTS

After controlling for confounding variables, average SVC flow over the first 24 hours of life was significantly associated with the primary outcome of death or survival with any disability (P=.004) and with the secondary outcome of abnormal developmental quotient (P = .006). A greater number of low SVC flow readings during the first 24 hours was significantly related to death and adverse developmental outcome, but the individual lowest SVC flow was not, suggesting the importance of duration of low SVC flow. After adjustment, there was no significant association between average mean blood pressure over the first 24 hours and abnormal developmental outcome, whereas the proportion of mean blood pressure readings less than the gestational age showed a trend toward an association with death and any disability.

CONCLUSIONS

Low early postnatal blood flow to the upper body and brain may be one factor in the causal pathway of impaired preterm neurodevelopmental outcome.

Neonatal electroencephalogram does not predict cognitive and academic achievement scores at early school age in survivors of neonatal extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation is an effective rescue treatment for severe cardiorespiratory failure in term or near-term neonates, although a wide range of neurologic sequelae have been noted in a substantial minority of survivors. The objective of the present study was to determine the value of the neonatal electroencephalogram (EEG) for predicting Wechler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R), Wide Range Achievement Test, and Wide Range Assessment of Memory and Language scores at early school age in 66 testable survivors of extracorporeal membrane oxygenation who were not severely brain damaged. Technically satisfactory EEG recordings were obtained at least twice following admission to our nursery and prior to discharge. The EEGs were classified and graded according to standard criteria. The developmental test results of those who had only normal or mildly abnormal neonatal EEGs (group 1, n = 9) were compared with those who had at least one moderately or markedly abnormal recording (group 2, n = 57). School-age test and subtest scores were not statistically significantly worse in group 2 versus group 1 infants. No child in group 1 and five children in group 2 had WPPSI-R Full-Scale IQ scores of less than 70. Of the nine children in group 2 who had at least one markedly abnormal neonatal EEG recording (graded as burst suppression or as electrographic seizure), only two had abnormally low WPPSI-R Full-Scale IQ scores. We conclude that EEG recordings obtained during the neonatal course of neonates treated with extracorporeal membrane oxygenation do not predict cognitive and academic achievement test results in survivors at early school age who were testable and not severely brain damaged.

Care of the surgical intensive care nursery graduate. The primary care pediatrician's perspective

Care of the intensive care nursery graduate may be quite challenging. It is important that primary care pediatricians become familiar with the complications unique to surgical patients so that they may properly prepare and educate parents and provide appropriate long-term follow-up for these often complex patients. Maintenance of a close relationship with the pediatric surgeon with an open line of communication regarding the approach to various surgical problems facilitates the effective integration of the intensive care nursery graduate into the primary care pediatrician's practice and provides the foundation for a successful clinical outcome.

Sensitivity and specificity of the neonatal brain-stem auditory evoked potential for hearing and language deficits in survivors of extracorporeal membrane oxygenation

OBJECTIVE

We determined the sensitivity and specificity of neonatal brain-stem auditory evoked potentials (BAEP) as markers for subsequent hearing impairment and for developmental problems found later in infancy and childhood.

METHODS

BAEP studies were performed before discharge in infants treated with extracorporeal membrane oxygenation (ECMO), and two specific abnormalities were analyzed: elevated threshold and delayed central auditory conduction. Behavioral audiometry was repeated during periodic follow-up until reliable responses were obtained for all frequencies, and standardized developmental testing was also conducted. The sensitivity and specificity of an elevated threshold on the neonatal BAEP for detecting subsequent hearing loss, and the relationship of any neonatal BAEP abnormality to language or developmental disorders in infancy, were calculated.

RESULTS

Test results for 46 ECMO-treated infants (57.5%) were normal, and those for 34 infants (42.5%) were abnormal, with either elevated wave V threshold, prolonged wave I-V interval, or both on neonatal BAEP recordings. Most significantly, 7 (58%) of the 12 children with subsequent sensorineural hearing loss had left the hospital after showing normal results on threshold tests. There was no significant difference in the frequency of hearing loss between subjects with abnormal (5/21, or 24%) and those with normal BAEP thresholds (7/59, or 12%; Fisher Exact Test, p = 0.28). Therefore the sensitivity of neonatal BAEP testing for predicting subsequent hearing loss was only 42%. Neonatal BAEP specificity for excluding subsequent hearing loss was 76%. In contrast, on language development testing, 19 children demonstrated receptive language delay. Of these children, 12 (63%) had abnormal neonatal BAEP recordings and 7 (37%) had a normal BAEP threshold, normal central auditory conduction test results, or both (p = 0.04).

CONCLUSIONS

Neonatal BAEP threshold recordings were of limited value for predicting subsequent hearing loss common in ECMO-treated survivors. However, an abnormal neonatal BAEP significantly increased the probability of finding a receptive language delay during early childhood, even in those with subsequently normal audiometry findings. Because neonatal ECMO is associated with a high risk of hearing and receptive language disorders, parents should be counseled that audiologic and developmental follow-up evaluations in surviving children are essential regardless of the results of neonatal BAEP testing.