Right common carotid artery ligation in extracorporeal membrane oxygenation

Incidence, risk factors, and management following cardiac catheterization via carotid and axillary artery approaches: A single-center experience on pseudoaneurysms in young infants

BACKGROUND

Use of alternate access for complex neonatal interventions has gained acceptance with carotid and axillary artery access being used for ductal and aortic interventions.

METHODS

This study was a retrospective, single-center study at Cincinnati Children's Hospital Medical Center. The study included infants, aged ≤90 days, who underwent cardiac catheterization with either carotid or axillary artery access between 2013 and 2022. Data encompassing demographics, clinical information, catheterization data, and the incidence of pseudoaneurysm as a procedural complication were collected.

RESULTS

Among 29 young infants (20 males, 69%), 4 out of 15 patients (27%) who underwent the carotid approach developed pseudoaneurysms, while 1 out of 14 patients (7.1%) who underwent the axillary approach developed one. Two patients required transcatheter intervention due to enlargement of pseudoaneurysms, involving the placement of transarterial flow-diverting stent and occlusion of left common carotid artery. Longer sheath in-to-out time (135 vs. 77 min, p = 0.001), and higher closing activated clotting times (ACT) (268 vs. 197 s, p = 0.021) were observed among patients with pseudoaneurysms compared to those without.

CONCLUSIONS

Young infants with alternative access via the carotid and axillary arteries may be at risk of pseudoaneurysm formation during longer procedures and with higher ACTs for closure. Ultrasound-guided compression can be employed to prevent the progression and in resolution of these lesions.

Veno-arterial extracorporeal membrane oxygenation for respiratory and cardiac support in neonates: a single center experience

Objective

Extracorporeal membrane oxygenation (ECMO) is an advanced life support that has been utilized in the neonate for refractory respiratory and circulatory failure. Striving for the best outcomes and understanding optimal surgical techniques continue to be at the forefront of discussion and research. This study presents a single-center experience of cervically cannulated neonatal patients on V-A ECMO, a description of our cannulation/decannulation techniques and our patient outcomes.

Methods

Single center retrospective review of neonates who received neck V-A ECMO support from January 2012 to December 2022. The data and outcomes of the patients were retrospectively analyzed.

Results

A total of 78 neonates received V-A ECMO support. There were 66 patients that received ECMO for respiratory support, the other 12 patients that received ECMO for cardiac support. The median duration of ECMO support was 109 (32-293) hours for all patients. During ECMO support, 20 patients died and 5 patients discontinued treatment due to poor outcome or the cost. A total of 53 (68%) patients were successfully weaned from ECMO, but 3 of them died in the subsequent treatment. Overall 50 (64%) patients survived to hospital discharge. In this study, 48 patients were cannulated using the vessel sparing technique, the other 30 patients were cannulated using the ligation technique. We found no significant difference in the rates of normal cranial MRI at discharge between survivors with and without common carotid artery ligation.

Conclusion

We achieved satisfactory outcomes of neonatal ECMO in 11-year experience. This study found no significant difference in early neuroimaging between survivors with and without common carotid artery ligation. The long-term neurological function of ECMO survivors warranted further follow-up and study.

Carotid Artery Patency and Neurodevelopmental Outcomes After Decannulation in Pediatric Extracorporeal Life Support

INTRODUCTION

Decannulation from veno-arterial extracorporeal life support may involve ligation or repair of the carotid artery; however, differences in outcomes are not clear. This study aimed to describe short- and long-term artery patency and neurodevelopmental outcomes in neonatal and pediatric patients who underwent carotid artery repair (CAR) versus ligation at decannulation.

METHODS

Patients supported on veno-arterial extracorporeal life support during the first 15 mo of life from 2010 to 2020 at a large, tertiary care children's hospital were included. Decannulation strategy, postdecannulation imaging, and follow-up visits were reviewed.

RESULTS

74 patients were identified with median age at cannulation 2 d (interquartile range [IQR] = 1-21 d) and median weight 3.7 kg (interquartile range= 3.2-4.4 kg). Indications included congenital cardiac conditions (27%), congenital diaphragmatic hernia (19%), pulmonary hypertension (19%), meconium aspiration (16%), and pneumonia/sepsis (14%). Forty-two patients (57%) underwent CAR. Patients on extracorporeal life support >5 d were 95% less likely to undergo CAR (P < 0.001). Of CAR patients, 18 (43%) had doppler ultrasound performed within the 2-y follow-up period. Ten of 18 patients (55.6%) had >50% stenosis (3) or complete occlusion (7). Only 36% (27/74) had formal neurodevelopmental follow-up within 6 mo and 41% (30/74) within 2 y; however, no significant differences in function were seen between groups.

CONCLUSIONS

Neonates and young toddler patients undergoing CAR following extracorporeal life support decannulation are at risk for partial or complete artery occlusion. In our study population, repair and ligation at decannulation appear to have similar neurodevelopmental outcomes; however, follow-up to assess function is not standardized. Longer term follow-up and risk stratification are needed to guide decannulation strategy.

Vascular Reconstruction After Cannulation for Support With Extracorporeal Membrane Oxygenation: Literature Review of Data in the Pediatric Population

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) is an invaluable life-support resource in the treatment of critically ill children. Traditionally, neck vascular cannulation requires ligation of the carotid artery and jugular vein. In this literature review, we identify rates of postoperative vessel patency, complications, and neurologic outcomes after vascular reconstruction following decannulation.

DATA SOURCES

Embase, PubMed, and Cochrane Review.

STUDY SELECTION

No publication date limits. Inclusion criteria comprised of studies addressing repair of the carotid artery and jugular vein after ECMO decannulation and outcomes from this procedure.

DATA EXTRACTION

Authors identified publications on vascular reconstruction after ECMO decannulation, including possible technical considerations, complications, and outcomes.

DATA SYNTHESIS

We identified 18 articles: 13 studies were limited to the neonatal population. The largest series included 51 patients after vascular reconstruction. The rate of postoperative arterial occlusion ranged from 11.8% to 17.8%, and overall patency rate postoperatively was 78.6%. No major thromboembolic events were reported. One study demonstrated an increase in neuroimaging abnormalities for patients undergoing ligation compared with vascular reconstruction. No studies demonstrated differences in functional neurodevelopmental testing.

CONCLUSIONS

Vascular reconstruction after ECMO decannulation has been reported since 1990. Although reconstruction does not appear to carry significant short-term morbidity, there are no large prospective studies or randomized controlled trials demonstrating its efficacy in improving neurologic outcomes in ECMO patients. There is also a paucity of data regarding outcomes in older children or long-term ramifications of vascular reconstruction.

Surgical experience in repairing the right common carotid artery and the right internal jugular vein after ECMO in neonates: early clinical results

BACKGROUND

The purpose of this study was to summarize the early clinical results and surgical experience of repairing the right common carotid artery and the right internal jugular vein after ECMO treatment in neonates.

METHODS

We retrospectively collected the clinical data of 16 neonates with circulatory and respiratory failure who were treated with ECMO via the right common carotid artery and the right internal jugular vein in our hospital from June 2021 to December 2022. The effects of repairing the common carotid artery and internal jugular vein were evaluated.

RESULTS

All 16 patients successfully underwent right cervical vascular cannulation, and the ECMO cycle was successfully established. Twelve patients were successfully removed from ECMO. The right common carotid artery and the right internal jugular vein were successfully repaired in these 12 patients. There was unobstructed arterial blood flow in 9 patients, mild stenosis in 1 patient, moderate stenosis in 1 patient and obstruction in 1 patient. There was unobstructed venous blood flow in 10 patients, mild stenosis in 1 patient, and moderate stenosis in 1 patient. No thrombosis was found in the right internal jugular vein. Thrombosis was found in the right common carotid artery of one patient.

CONCLUSION

Repairing the right common carotid artery and the right internal jugular vein after ECMO treatment in neonates was feasible, and careful surgical anastomosis techniques and standardized postoperative anticoagulation management can ensure early vascular patency. However, long-term vascular patency is still being assessed in follow-up.

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.

Cannulation and decannulation techniques for neonatal ECMO

In neonates with cardiac and/or respiratory failure, extracorporeal membrane oxygenation (ECMO) continues to be an important method of respiratory and/or cardiovascular support where conventional treatments are failing. ECMO cannulation involves a complex decision-making process to choose the proper ECMO modality and cannulation strategy to match each patient's needs, unique anatomy, and potential complication profile. Initially, all ECMO support involved cannulating both the carotid artery and the internal jugular vein (IJV), known as veno-arterial (VA-ECMO) for cardiac and/or respiratory support. Rarely was cannulation through the chest used. The development of dual-lumen cannulae in the early to mid 1990s addressed the concerns about carotid artery ligation and its impact on neurological outcomes, and allowed single vascular access for veno-venous respiratory support (VV-ECMO). We present a review of cannulation and decannulation techniques for both VA and VV-ECMO in neonates.

ECMO in neonates: The association between cerebral hemodynamics with neurological function

Extracorporeal membrane oxygenation (ECMO) is a superior life support technology, commonly employed in critical patients with severe respiratory or hemodynamic failure to provide effective respiratory and circulatory support, which is especially recommended for the treatment of critical neonates. However, the vascular management of neonates with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is still under controversy. Reconstruction or ligation for the right common carotid artery (RCCA) after ECMO is inconclusive. This review summarized the existed studies on hemodynamics and neurological function after vascular ligation or reconstruction hoping to provide better strategies for vessel management in newborns after ECMO. After reconstruction, the right cerebral blood flow can increase immediately, and the normal blood supply can be restored rapidly. But the reconstructed vessel may be occluded and stenotic in long-term follow-ups. Ligation may cause lateralization damage, but there could be no significant effect owing to the establishment of collateral circulation. The completion of the circle of Willis, the congenital anomalies of cerebral or cervical vasculature, the duration of ECMO, and the vascular condition at the site of arterial catheterization should be assessed carefully before making the decision. It is also necessary to follow up on the reconstructed vessel sustainability, and the association between cerebral hemodynamics and neurological function requires further large-scale multi-center studies.

Common carotid artery imaging after vessel sparing decannulation from Extracorporeal Membrane Oxygenation (ECMO) support

INTRODUCTION

In 2008, Children's National Hospital adopted a simple vessel sparing technique (VST) for neck extra corporeal membrane (ECMO) cannulation/decannulation that is technically simple and reproducible. In this study, we review a cohort of patients decannulated from venous-arterial (VA) ECMO using a VST with the goal of understanding flow dynamics and anatomic changes of the common carotid artery (CCA) after repair with a VST.

METHODS

Patients supported with ECMO at a single, tertiary care center between 2008 and 2019 were identified. Patients were included in the analysis if they survived VA ECMO including VST decannulation and neck vessel imaging was completed with either magnetic resonance angiogram (MRA) or computerized tomography angiogram (CTA) post decannulation. The right CCA was assessed for patency and arteriopathy. Complications and feasibility of repeat ECMO cannulation via the neck vessels were also investigated.

RESULTS

Three hundred and nineteen patients were identified as having received ECMO support in either the PICU or CICU between 2008 and 2019, of which 76 survived VA ECMO support via neck cannulation. Neck vessel imaging was obtained in 21 patients. Ten had imaging demonstrating a normal right CCA. The CCA was occluded in 3 and stenotic in 5. Vessel wall defects were present in 4. No definitive complication was associated with any of the arterial abnormalities. Repeat right CCA cannulation was achieved in 6/7 patients who needed additional VA ECMO support.

CONCLUSIONS

Repair of the right CCA with a simple VST can be achieved safely and consistently during VA ECMO support in pediatric patients. Vascular imaging of the right CCA was normal in almost half and repeat cannulation was achieved in most when pursued. Stenosis and vessel wall defects were common, thus neck vessel imaging post decannulation may be warranted for all patients with a right CCA repair after ECMO support.

EEG features of brain injury during extracorporeal membrane oxygenation in children

OBJECTIVE

To examine EEG features of major pathophysiology in children undergoing extracorporeal membrane oxygenation (ECMO).

METHODS

This was a single-center, retrospective study of 201 pediatric patients on ECMO, using the first 24 hours of continuous EEG (cEEG) monitoring, collating background activity and electrographic seizures (ES) with imaging, ECMO type, and outcome.

RESULTS

Severely abnormal cEEG background occurred in 12% (25/201), and was associated with death (sensitivity 0.23, specificity 0.97). ES occurred in 16% (33/201) within 3.2 (0.6-20.3) hours (median [interquartile range]) of cEEG commencement, and higher ES burden was associated with death. ES was always associated with ipsilateral injury (p = 0.006), but occurred in only one-third of cases with abnormal imaging. In 28 patients with isolated hemisphere lesion, type of arterial ECMO cannulation was associated with side of injury: right carotid cannulation was associated with right hemisphere lesions, and ascending aorta cannulation with left hemisphere lesions (odds ratio, 0.29 [95% confidence interval, 0.08-0.98], p = 0.03).

CONCLUSIONS

After starting ECMO, cEEG background activity has the potential to inform prognosis. Type of arterial (carotid vs aortic) ECMO correlates with side of focal cerebral injury, which in ≈33% is associated with presence of ES. We hypothesize that the differential distribution reflects abnormal flow dynamics or embolic injury.

Cerebral Oxygenation of Premature Lambs Supported by an Artificial Placenta

An artificial placenta (AP) using venovenous extracorporeal life support (VV-ECLS) could represent a paradigm shift in the treatment of extremely premature infants. However, AP support could potentially alter cerebral oxygen delivery. We assessed cerebral perfusion in fetal lambs on AP support using near-infrared spectroscopy (NIRS) and carotid arterial flow (CAF). Fourteen premature lambs at estimated gestational age (EGA) 130 days (term = 145) underwent cannulation of the right jugular vein and umbilical vein with initiation of VV-ECLS. An ultrasonic flow probe was placed around the right carotid artery (CA), and a NIRS sensor was placed on the scalp. Lambs were not ventilated. CAF, percentage of regional oxygen saturation (rSO2) as measured by NIRS, hemodynamic data, and blood gases were collected at baseline (native placental support) and regularly during AP support. Fetal lambs were maintained on AP support for a mean of 55 ± 27 hours. Baseline rSO2 on native placental support was 40% ± 3%, compared with a mean rSO2 during AP support of 50% ± 11% (p = 0.027). Baseline CAF was 27.4 ± 5.4 ml/kg/min compared with an average CAF of 23.7 ± 7.7 ml/kg/min during AP support. Cerebral fractional tissue oxygen extraction (FTOE) correlated negatively with CAF (r = -0.382; p < 0.001) and mean arterial pressure (r = -0.425; p < 0.001). FTOE weakly correlated with systemic O2 saturation (r = 0.091; p = 0.017). Cerebral oxygenation and blood flow in premature lambs are maintained during support with an AP. Cerebral O2 extraction is inversely related to carotid flow and is weakly correlated with systemic O2 saturation.

Improving Long-Term Outcomes After Extracorporeal Membrane Oxygenation: From Observational Follow-Up Programs Toward Risk Stratification

Since the introduction of extracorporeal membrane oxygenation (ECMO), more neonates and children with cardiorespiratory failure survive. Interest has therefore shifted from reduction of mortality toward evaluation of long-term outcomes and prevention of morbidity. This review addresses the changes in ECMO population and the ECMO-treatment that may affect long-term outcomes, the diagnostic modalities to evaluate neurological morbidities and their contributions to prognostication of long-term outcomes. Most follow-up data have only become available from observational follow-up programs in neonatal ECMO-survivors. The main topics are discussed in this review. Recommendations for long-term follow up depend on the presence of neurological comorbidity, the nature and extent of the underlying disease, and the indication for ECMO. Follow up should preferably be offered as standard of care, and in an interdisciplinary, structured and standardized way. This permits evaluation of outcome data and effect of interventions. We propose a standardized approach and recommend that multiple domains should be evaluated during long-term follow up of neonates and children who needed extracorporeal life support.

Transcranial Doppler Identification of Neurologic Injury during Pediatric Extracorporeal Membrane Oxygenation Therapy

BACKGROUND

We used transcranial Doppler to examine changes in cerebral blood flow velocity in children treated with extracorporeal membrane oxygenation. We examined the association between those changes and radiologic, electroencephalographic, and clinical evidence of neurologic injury.

METHODS

This was a retrospective review and prospective observational study of patients 18 years old and younger at a single university children's hospital. Transcranial Doppler studies were obtained every other day during the first 7 days of extracorporeal membrane oxygenation, and 1 additional study following decannulation, in conjunction with serial neurologic examinations, brain imaging, and 6- to 12-month follow-up.

RESULTS

The study included 27 patients, the majority (26) receiving veno-arterial extracorporeal membrane oxygenation. Transcranial Doppler velocities during extracorporeal membrane oxygenation were significantly lower than published values for age-matched healthy and critically ill children across different cerebral arteries. Neonates younger than 10 days had higher velocities than expected. Blood flow velocity increased after extracorporeal membrane oxygenation decannulation and was comparable with age-matched critically ill children. There was no significant association between velocity measurements of individual arteries and acute neurologic injury as defined by either abnormal neurologic examination, seizures during admission, or poor pediatric cerebral performance category. However, case analysis identified several patients with regional and global increases in velocities that corresponded to neurologic injury including stroke and seizures.

CONCLUSIONS

Cerebral blood flow velocities during extracorporeal membrane oxygenation deviate from age-specific normal values in all major cerebral vessels and across different age groups. Global or regional elevations and asymmetries in flow velocity may suggest impending neurologic injury.

Prognostic value of cerebral tissue oxygen saturation during neonatal extracorporeal membrane oxygenation

Objectives

Extracorporeal membrane oxygenation support is indicated in severe and refractory respiratory or circulatory failures. Neurological complications are typically represented by acute ischemic or hemorrhagic lesions, which induce higher morbidity and mortality. The primary goal of this study was to assess the prognostic value of cerebral tissue oxygen saturation (StcO₂) on mortality in neonates and young infants treated with ECMO. A secondary objective was to evaluate the association between StcO₂ and the occurrence of cerebral lesions.

Study design

This was a prospective study in infants < 3 months of age admitted to a pediatric intensive care unit and requiring ECMO support.

Measurements

The assessment of cerebral perfusion was made by continuous StcO₂ monitoring using near-infrared spectroscopy (NIRS) sensors placed on the two temporo-parietal regions. Neurological lesions were identified by MRI or transfontanellar echography.

Results

Thirty-four infants <3 months of age were included in the study over a period of 18 months. The ECMO duration was 10±7 days. The survival rate was 50% (17/34 patients), and the proportion of brain injuries was 20% (7/34 patients). The mean StcO₂ during ECMO in the non-survivors was reduced in both hemispheres (p = 0.0008 right, p = 0.03 left) compared to the survivors. StcO₂ was also reduced in deceased or brain-injured patients compared to the survivors without brain injury (p = 0.002).

Conclusion

StcO₂ appears to be a strong prognostic factor of survival and of the presence of cerebral lesions in young infants during ECMO.

Neonatal carotid repair at ECMO decannulation: patency rates and early neurologic outcomes

PURPOSE

Neonates placed on veno-arterial extracorporeal membrane oxygenation (VA-ECMO) undergo either carotid repair or ligation at decannulation. Study aims were to evaluate carotid patency rates after repair and to compare early neurologic outcomes between repaired and ligated patients.

METHODS

A retrospective study of all neonates without congenital heart disease (CHD) who had VA-ECMO between 1989 and 2012 was completed using our institutional ECMO Registry. Carotid patency after repair, neuroimaging studies, and auditory brainstem response (ABR) testing at time of discharge were examined.

RESULTS

140 neonates were placed on VA-ECMO during the study period. Among survivors, 84% of carotids repaired and imaged remained patent at last study. No significant differences were observed between infants in the repaired and ligated groups regarding diagnosis, ECMO duration, or length of stay. A large proportion (43%) developed a severe brain lesion after VA-ECMO, but few failed their ABR testing. Differences in early neurologic outcomes between the two groups of survivors were not significant.

CONCLUSIONS

At this single institution, carotid patency is excellent following repair at ECMO decannulation. No increased incidence of severe brain lesions or greater neurosensory impairment in the repair group was observed. Further studies are needed to investigate the effects of ligation on longer-term neurocognitive outcomes.

ECMO in neonates: neuroimaging findings and outcome

Extracorporeal membrane oxygenation (ECMO) is a rescue therapy for newborns with severe but reversible respiratory failure. Although ECMO has significantly improved survival, it is associated with substantial complications, of which intracranial injuries are the most important. These injuries consist of hemorrhagic and non-hemorrhagic, ischemic lesions. Different from the classical presentation of hemorrhages in preterm infants, hemorrhages in ECMO-treated newborns are mainly parenchymal and with a high percentage in the posterior fossa area. There are conflicting data on the predominant occurrence of cerebral lesions in the right hemisphere. The existence of intracerebral injuries and the classification of its severity are the major predictors of neurodevelopmental outcome. This section will discuss the known data on intracranial injury in the ECMO population and the effect of ECMO on the brain.

Brain injury associated with neonatal extracorporeal membrane oxygenation in the Netherlands: a nationwide evaluation spanning two decades

OBJECTIVE

To determine the prevalence of and to classify ultrasound-proven brain injury during neonatal extracorporeal membrane oxygenation in The Netherlands.

DESIGN

Retrospective nationwide study (Rotterdam and Nijmegen), spanning two decades.

SETTING

Level III university hospitals.

SUBJECTS

All neonates who underwent neonatal extracorporeal membrane oxygenation from 1989 to 2010.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cranial ultrasound images were reviewed independently by two investigators without knowledge of primary diagnosis, outcome, type of extracorporeal membrane oxygenation, or statistics. The scans were reviewed for lesion type and timing, with the use of a refined classification method for focal brain injury. Extracorporeal membrane oxygenation type was venoarterial in 88%. Brain abnormalities were detected in 17.3%: primary hemorrhage was most frequent (8.8%). Stroke was identified in 5% of the total group, with a notable significant preference for the left hemisphere (in 70%). Lobar hematoma (prevalence 2.2 %) was also significantly left predominant.

CONCLUSION

The incidence of brain injury found with cranial ultrasound in The Netherlands of the patients treated with extracorporeal membrane oxygenation during the neonatal period was 17.3%. Primary hemorrhage was the largest group of lesions, not clearly side-specific except for lobar bleeding, most probably related to changes in venous flow. Arterial ischemic stroke occurred predominant in the left hemisphere.

Cerebral aspects of neonatal extracorporeal membrane oxygenation: a review

BACKGROUND

Neonatal extracorporeal membrane oxygenation (ECMO) is a lifesaving therapeutic approach in newborns suffering from severe, but potentially reversible, respiratory insufficiency, mostly complicated by neonatal persistent pulmonary hypertension. However, cerebral damage, intracerebral hemorrhage as well as ischemia belong to the most devastating complications of ECMO.

OBJECTIVES

The objectives are to give insights into what is known from the literature concerning cerebral damage related to neonatal ECMO treatment for pulmonary reasons.

METHODS

A short introduction to ECMO indications and technical aspects of ECMO are provided for a better understanding of the process. The remainder of this review focuses on outcome and especially on (potential) risk factors for cerebral hemorrhage and ischemia during ECMO treatment.

RESULTS

Although neonatal ECMO treatment shows improved outcome compared to conservative treatment in cases of severe respiratory insufficiency, it is related to disturbances in various aspects of neurodevelopmental outcome. Risk factors for cerebral damage are either related to the patient's disease, EMCO treatment itself, or a combination of both.

CONCLUSION

It is of ongoing importance to further understand pathophysiological mechanisms resulting in cerebral hemorrhage and ischemia due to ECMO and to develop neuroprotective strategies and approaches.

Effect of bladderbox alarms during venoarterial extracorporeal membrane oxygenation on cerebral oxygenation and hemodynamics in lambs

To determine the effects of bladderbox alarms during venoarterial extracorporeal membrane oxygenation (va-ECMO) on cerebral oxygenation and hemodynamics, six lambs were prospectively treated with va-ECMO and bladderbox alarms were simulated. Changes in concentrations of oxyhemoglobin (deltacO2Hb), deoxyhemoglobin (deltacHHb), and total Hb (deltactHb) were measured using near infrared spectrophotometry. Fluctuations in Hb oxygenation index (deltaHbD) and cerebral blood volume (deltaCBV) were calculated. Heart rate (HR), mean arterial pressure (MAP), blood flow in the left carotid artery (Qcar), and central venous pressure (CVP) were registered. Bladderbox alarms were simulated by increasing the ECMO flow or partially clamping the venous cannula and resolved by decreasing the ECMO flow, unclamping the cannula, or intravascular volume administration. CBV, HbD, MAP, and Qcar decreased significantly during bladderbox alarms, whereas HR and CVP increased. After the bladderbox alarms, CBV and HbD increased significantly to values above baseline. For HbD, this increase was higher during intravascular volume administration.MAP, Qcar, and CVP recovered to preexperiment values but increased further with volume administration. HR was increased at the end of our measurements. We conclude that Bladderbox alarms during va-ECMO treatment result in significant fluctuations in cerebral oxygenation and hemodynamics, a possible risk factor for intracranial lesions.

Sonographic stroke templates

This chapter provides arterial and venous stroke templates, designed with neonatal brain ultrasound as the viewpoint and adult stroke templates as the basis. Images change with maturation of the stages of infarction: swelling, necrosis, organisation and tissue loss. Adult templates permit recognition of well-delineated stroke types observed in the newborn brain. All circle of Willis arteries can be involved, as can their perforator branches. Middle cerebral artery (MCA) truncal stroke (anterior or posterior) is an important entity, with different prognosis than complete MCA stroke. Knowledge of these templates also aids in the definition of combinations of infarction (e.g. internal carotid artery stroke or pial plus perforator stroke) and of interarterial watershed injury. Venous templates, even if still under development around the time of birth, permit us to understand brain injury associated with sinus or deep vein thrombosis, especially several types of intracranial haemorrhage. Hindbrain stroke templates are scarcely applied to perinatal lesions.

Systemic hyperthermia induces ischemic brain injury in neonatal mice with ligated carotid artery and jugular vein

Postnatal d 7 (p7) or p12 mice had their right carotid artery (CA) and jugular vein (JV) ligated to mimic veno-arterial (VA) access for extracorporeal membrane oxygenation (ECMO). At p9-11 (early) or p19-21 (late) mice were exposed to hyperthermia or normothermia followed by assessment of neuropathological injury score. In separate cohorts of mice, cerebral and peripheral blood flow (CBF, PBF) and cerebral ATP content was measured. Hyperthermia resulted in ischemic brain injury in 57% and 77% of mice subjected to early or late hyperthermia, respectively. Isolated CA+JV ligation induced minimal injury (score 0.47 +/- 0.34) in 2/8 mice from the late normothermia group. No cerebral injury was detected in mice subjected to early normothermia. In 3/19 shams (2/10 early, 1/9 late) hyperthermia induced a subtle (score, 0.6 +/- 0.27) injury in the ipsilateral to the site of surgery cortex. CBF and PBF increased in response to hyperthermia in all mice. The rise in CBF was significantly attenuated in the "ligated" versus intact hemisphere, which was associated with a profound depletion of ATP content. Systemic hyperthermia induces ischemic brain injury in mice with ligated CA+JV. We speculate that hyperthermia/fever can be a potential risk factor for brain injury in infants treated with VA ECMO.

Cerebral blood flow and oxygenation during venoarterial and venovenous extracorporeal membrane oxygenation in the newborn lamb

BACKGROUND

Concern exists that extracorporeal membrane oxygenation (ECMO) may decrease cerebral blood flow (CBF), impair cerebral autoregulation, and thereby increase the risk of neurologic injury.

OBJECTIVE

This study was undertaken in newborn lambs to compare the effects of initiation of venoarterial and venovenous ECMO on CBF and cerebral oxygen delivery as measured by laser-Doppler flowmetry. This study also evaluates the effects of carotid artery and jugular vein ligation on CBF.

DESIGN

CBF, arterial blood pressure, sagittal sinus pressure, heart rate, cardiac output, arterial blood gases, and hemoglobin saturation were measured. After anesthesia, instrumentation, and a 1-2 hr stabilization period, values were recorded during a 30-min control period, and the carotid artery or jugular vein was cannulated. The animals were then studied during venoarterial or venovenous ECMO for 1 hr.

MAIN RESULTS

Carotid ligation resulted in a transient decrease in right cortex CBF that resolved within 60 secs. Next, during a 60-min period of venoarterial ECMO (flow rate of 100 mL.min(-1).kg(-1), n = 11), cerebral resistance to flow increased, CBF decreased 25%, and cerebral oxygen delivery decreased by 30%. Native cardiac output and Paco(2) remained constant. Pulsatility in the lingual artery, representing the pulsatility of arterial flow to the brain, decreased throughout venoarterial ECMO. In contrast, in those lambs receiving ECMO in the venovenous mode (n = 7), resistance to flow, CBF, cerebral oxygen delivery, and pulsatility did not change.

CONCLUSIONS

There was no sustained decrease in CBF after ligation of either the carotid artery or jugular vein. Venoarterial but not venovenous ECMO induced decreases of CBF that could not be attributed to changes in blood gases or blood pressure but that may relate to diminished pulsatility in cerebral resistance vessels or to differences in levels of circulating vasoactive compounds.

Oxygenation and hemodynamics in left and right cerebral hemispheres during induction of veno-arterial extracorporeal membrane oxygenation

OBJECTIVE

Oxygenation and hemodynamics in the left and right cerebral hemispheres were measured during induction of veno-arterial extracorporeal membrane oxygenation (VA-ECMO).

STUDY DESIGN

Using near infrared spectrophotometry, effects of right common carotid artery (RCCA) and right internal jugular vein (RIJV) ligation and start of VA-ECMO on concentrations of oxyhemoglobin, deoxyhemoglobin, and cerebral blood volume (CBV) were evaluated in 10 newborn infants. Mean cerebral blood flow velocity (CBFV) in the major cerebral arteries was compared before and after the start of VA-ECMO (pulsed Doppler ultrasonography).

RESULTS

RCCA ligation caused a decrease in oxyhemoglobin concentration and an increase in deoxyhemoglobin concentration. RIJV ligation caused no changes. Sixty minutes after the start of VA-ECMO, oxyhemoglobin concentration and CBV had increased, and deoxyhemoglobin concentration had decreased. There were no differences between the hemispheres. Mean CBFV had increased in the left internal carotid artery, and it increased equally in both middle cerebral arteries. Flow direction was reversed in the right internal carotid artery. Three patients had asymmetric cerebral lesions, not related to differences in the measurements between the cerebral hemispheres.

CONCLUSION

The initiation of VA-ECMO causes changes in cerebral oxygenation and hemodynamics but without a difference in effect on left and right cerebral hemispheres.

Venoarterial versus venovenous extracorporeal membrane oxygenation in congenital diaphragmatic hernia: the Extracorporeal Life Support Organization Registry, 1990-1999

BACKGROUND/PURPOSE

Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) traditionally has been the mode of support used in congenital diaphragmatic hernia (CDH). A few studies report success using venovenous (VV) ECMO. The purpose of this study is to compare outcomes in CDH patients treated with VA and VV.

METHODS

The authors queried the Extracorporeal Life Support Organization Registry for newborns with CDH treated with ECMO from January 1, 1990 through December 31, 1999. They analyzed the pre-ECMO data, ECMO course, and complications.

RESULTS

VA was utilized in 2,257 (86%) and VV in 371 (14%) patients. The pre-ECMO status was similar, with greater use of nitric oxide, surfactant, and pressors in VV. Survival rate was similar (58.4% for VV and 52.2% for VA, P =.057). VA was associated with more seizures (12.3% v 6.7%, P =.0024) and cerebral infarction (10.5% v 6.7%, P =.03). Sixty-four treatments were converted from VV to VA (VV-->VA). Survival rate in VV-->VA was not significantly different than VA (43.8% v 52.2%, respectively; P =.23). VV-->VA and VA patients had similar neurologic complications.

CONCLUSIONS

CDH patients treated with VV and VA have similar survival rates. VA had more neurologic complications. The authors identified no disadvantage to the use of VV as an initial mode of ECMO for CDH, although some infants may need conversion to VA.

Five-year follow-up of neonates with reconstructed right common carotid arteries after extracorporeal membrane oxygenation

OBJECTIVE

Serial Doppler ultrasonography and long-term neurodevelopmental follow-up outcomes were evaluated prospectively in neonates whose right common carotid artery (RCCA) was reconstructed after extracorporeal membrane oxygenation (ECMO).

METHODS

Children with RCCA reconstruction (n = 34) were monitored for 3.5 to 4.5 years by Doppler ultrasonography for arterial patency, and 28 had IQ testing by 5 years. A comparison group consisted of 35 infants who had RCCA ligation after ECMO. Neonatal electroencephalograms and computed tomography/magnetic resonance imaging scans were also compared.

RESULTS

Reconstructions were successful (<50% RCCA stenosis by Doppler ultrasonography) in 26 (76%) of 34 children, 3 (9%) had >/=50% stenosis, and 5 (15%) had occlusion. No significant differences were seen between reconstructed and ligated groups in neonatal complications or ECMO courses. Occurrence of marked neonatal electroencephalographic abnormalities did not differ between groups. Abnormalities on computed tomography/magnetic resonance imaging scans (4 of 31 vs 11 of 29, P =.025) and cerebral palsy (0 of 34 vs 5 of 35, P =.054) were more common in infants with RCCA ligation. No differences were seen in developmental or IQ scores between the 2 groups, and 4 in each group had cognitive handicaps (at least 1 IQ score <70).

CONCLUSIONS

Most RCCA reconstructions remained patent, with 24% showing significant stenosis or occlusion. Compared with a historical control group, patients with RCCA reconstruction had fewer brain scan abnormalities and tended to be less likely to have cerebral palsy. RCCA reconstruction after venoarterial ECMO may improve outcome.

The Edmonton experience with venovenous extracorporeal membrane oxygenation

BACKGROUND/PURPOSE

Despite the proven effectiveness of venovenous extracorporeal membrane oxygenation (VV ECMO) in the treatment of neonates with severe respiratory failure, this technique is not widely used. The purpose of this study was to assess the authors' policy of preferred use of VV ECMO with a cephalad catheter and to compare the results with those of the Extracorporeal Life Support Organization (ELSO) Registry.

METHODS

Charts of neonatal ECMO candidates were reviewed retrospectively. Data were collected for gestational age, birth weight, and diagnosis. Severity of illness was assessed by oxygenation index, lactate levels, and inotropic requirements before cannulation. Patients were divided into three groups: venovenous (VV), venoarterial (VA), and VV to VA ECMO. A cephalad catheter was inserted in the distal part of the jugular vein.

RESULTS

Sixty-five neonates were supported with ECMO. Cannulation with a double lumen venovenous (VVDL) catheter was attempted in 63 neonates and successfully accomplished in 57. A survival rate of 86% was observed in neonates initially placed on VV ECMO. Five neonates initially placed on VV ECMO underwent conversion to VA ECMO.

CONCLUSIONS

This study showed that the authors' preferred policy of VV ECMO did not result in an increase in mortality rate based on a comparison with ELSO data. VV ECMO with a cephalad catheter provides adequate support for unstable neonates with respiratory failure.

MRI, MRA, and neurodevelopmental outcome following neonatal ECMO

Cranial magnetic resonance imaging (MRI) of 31 newborn infants treated with venoarterial cardiopulmonary bypass for severe but reversible respiratory failure, revealed major focal parenchymal lesions in 7 of 31 infants (23%) and demonstrated abnormal enlargement of extra-axial and ventricular cerebrospinal fluid spaces in 16 of 31 (51%). No preferential left versus right lateralization of focal injury was observed in conjunction with right common carotid artery and jugular vein ligation. No statistically significant relationships were found between major brain lesions on MRI scans and the clinical characteristics of the pre-extracorporeal membrane oxygenation (ECMO), ECMO, and post-ECMO course. Major focal brain lesions were significantly associated with an asymmetric cerebrovascular response to carotid ligation of the right versus left middle cerebral arteries as detected by magnetic resonance angiography (P < .05). Enlarged cerebrospinal fluid spaces were not significantly related to the presence of parenchymal MRI lesions, but were associated with lower Bayley neurodevelopmental scores for mental (MDI) and psychomotor evaluations (PDI) at 6 and 12 months (P < .05). It is concluded that asymmetries of cerebral vascular adaptation detected by magnetic resonance angiography after ECMO may be associated with major brain lesions revealed by MRI. Thereafter, the presence of enlarged cerebrospinal fluid spaces on MRI is associated with a poor shortterm developmental outcome.

Median nerve somatosensory evoked potentials in children receiving ECMO

Somatosensory evoked potentials (SEPs) were recorded from 11 patients receiving venoarterial extracorporeal membrane oxygenation (ECMO). Cortical responses recorded from the right and left hemispheres were compared to those from 2 other groups of children who were not receiving ECMO. One group consisted of 99 brain-injured patients, while the other consisted of a group of 17 neurologically normal controls. SEP responses from each hemisphere were categorized into 3 grades based on the N20 component--normal latency, abnormal (latency increased > 3 S.D.), or absent. For ECMO patients, 15% of tests disclosed a disagreement between the right and left hemispheres, while 27% of tests from the control group revealed a disagreement between the right and left hemispheres. SEPs were normal over the right hemisphere in 9 patients. Central conduction times obtained from the right and left hemispheres were similar in ECMO patients and were not different from those recorded from a group of patients suffering hypoxic-ischemic injuries and a group of normal controls who did not receive ECMO. The results of this pilot study suggest that SEPs may be employed to evaluate ECMO patients as they are in other brain-injured patients.

Predictive value of neonatal electroencephalograms before and during extracorporeal membrane oxygenation

We studied the prognostic significance of electroencephalograms recorded serially at 2- to 4-day intervals during the acute neonatal course of 119 near-term infants with severe respiratory failure treated by venoarterial extracorporeal membrane oxygenation (ECMO). A poor prognosis was defined as early death (n = 27), an abnormally low developmental assessment score (n = 14), or cerebral palsy (n = 14) at 12 to 45 months of age. The only electroencephalographic abnormalities that were significantly related to a poor prognosis were burst suppression (B-S) and electrographic seizure (ES). The 30 infants with two or more recordings of B-S or ES, when compared with the 58 neonates without such electroencephalographic abnormalities, had an odds ratio for a poor prognosis of 6.6 (95% confidence limits, 2.2 to 20.2). The 31 infants with a single ES or B-S recording did not have a significantly increased risk for a poor prognosis. Cardiopulmonary resuscitation immediately before ECMO (n = 8) and the lowest systolic blood pressure before or during ECMO were significantly related to the occurrence of ES or B-S recordings. There was no significant predilection of ES for either cerebral hemisphere. We conclude that in near-term neonates with respiratory failure, serial electroencephalographic recordings are of predictive value, and may facilitate clinical care including the decision to initiate or to continue ECMO.

Surgical repair of an aortic coarctation in a patient after treatment with extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a life-saving treatment for neonates who have severe respiratory failure that does not respond to maximal conventional therapy. A consequence of venoarterial ECMO is the sacrifice of the right common carotid artery. Evaluation of the impact of a single carotid artery in babies treated with ECMO concerns mostly long-term neurodevelopmental outcome. The authors encountered a peculiar problem caused by a single carotid artery in a post-ECMO patient during the surgical correction of aortic coarctation with hypoplastic distal aortic arch. For patients with a confirmed cardiac malformation that necessitates future surgical repair and for whom ECMO support is required, reconstruction of the right common carotid artery should be considered. Veno-venous ECMO is an alternative solution if this approach is not contraindicated because of the patient's clinical condition. Patients with congenital diaphragmatic hernia have a higher incidence of cardiac malformations; therefore, careful cardiological attention is required. Anomalies masked by pulmonary hypertension also must be considered.

Right common carotid artery reconstruction after extracorporeal membrane oxygenation: vascular imaging, cerebral circulation, electroencephalographic, and neurodevelopmental correlates to recovery

OBJECTIVE

Right common carotid artery (RCCA) ligation after extracorporeal membrane oxygenation by venoarterial bypass may contribute to lateralized cerebral injury. Reconstruction of this artery after extracorporeal membrane oxygenation has proved feasible but has not been evaluated for neurologic outcome in any substantial series of infants.

METHODS

We evaluated RCCA reconstruction in 47 infants treated with ECMO and compared their cerebrovascular and neuroanatomic imaging findings, electroencephalograms, and developmental outcomes with those of 93 infants who had no reconstruction. SUMMARY RESULTS: Color Doppler blood flow imaging revealed that carotid artery patency was usually obtained after RCCA reconstruction. Right internal carotid and bilateral anterior and middle cerebral arterial blood flow velocities were generally higher, and were more symmetrically distributed in infants with reconstructed RCCA. Electroencephalography did not disclose an increased risk of deterioration or marked abnormalities in infants after reconstruction, nor were neuroimaging findings consistent with an increased number of either focal or generalized abnormalities. Neurodevelopmental follow-up revealed no differences in the incidence of delays between those with a reconstructed RCCA and those with a ligated RCCA during the first year of life.

CONCLUSIONS

Reconstruction of the RCCA after extracorporeal membrane oxygenation may facilitate normal distribution of cerebral blood flow through the circle of Willis, and may augment both left and right middle cerebral artery blood flow immediately after decannulation. The long-term consequences of either ligation or reconstruction of the RCCA will require careful scrutiny, however, before either course is recommended routinely.

Complications of neonatal extracorporeal membrane oxygenation

From 1973-1985 to 1988 the average patient complications per case were 1.44 per case and significantly increased during 1990 to 1992 to 2.10 per case (Figure 3). During the same periods patient survival significantly decreased from 84% (1973-1985 to 1988, n = 2463) to 80% (1990 to 1992, n = 4005) (Figure 4). The association between total complication rates and survival rate was examined by regression analysis (Table 5). The correlation of patient complication rate and total complication rate with survival is highly significant; however, causality cannot be established. When comparing different entry criteria (Table 2) for incidence of mechanical and patient complications, no significant differences are apparent. This is not surprising since each of the entry criteria were designed to identify the same patient population. When premature neonates (> 35 weeks) were placed on ECMO, 36% of them had intracranial haemorrhage (ICH) with 62% mortality while only 12% of the neonates < 35 weeks had ICH and a 49% mortality. Similar findings were noted with low birthweight neonates (< 2.2 kg), 28% had ICH with 64% mortality while only 12% of the neonates > 2.2 kg had ICH with a 50% mortality. Selection criteria remain problematic for a variety of reasons. They cannot be viewed as absolute because of variability between centres. What represents likely 80% mortality in one centre may not apply to another. Historical controls are misleading because changing respiratory therapy strategies make historical populations difficult to compare. Also, once an ECMO centre becomes established, a more challenging group of patients will be attracted than previously was the case. Further, a single entry criterion cannot be generalized for all entry diagnoses. Criteria for an 80% predicted mortality is probably not the same for MAS, CHN, PPHN, and sepsis. Subsequent patients registered in the Neonatal ECMO Registry of the Extracorporeal Life Support Organization will address these issues more thoroughly, as specific details of the pre-ECMO condition and therapeutic strategies are collected. This collective review should help to identify trends which require reassessment of technique or patient management.

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

Color Doppler imaging revealed a subclavian steal--retrograde flow in the right vertebral artery which shunted blood from the brain's posterior circulation to the right arm via the subclavian artery--in 17 of 54 infants (31%) during extracorporeal membrane oxygenation (ECMO); right vertebral artery flow returned to antegrade after ECMO and removal of the right common carotid arterial cannula. When subjects with and without a subclavian steal were compared, there were no statistically significant differences in mortality; in the results of neonatal electroencephalograms, cranial ultrasound studies, or computed tomography studies; or in early neurological development. Blood flow patterns and peak systolic velocities in the circle of Willis, middle cerebral arteries, internal carotid arteries, and basilar artery were similar in both groups during ECMO; blood flow velocity in the middle cerebral arteries was slightly but significantly lower on the right than the left in both groups. Our results indicate that increased flow in the left vertebral artery adequately compensated for the effect of a subclavian steal on the basilar and cerebral circulation. The moderate to marked neonatal electroencephalographic abnormalities commonly occurring during ECMO and the approximately 20% incidence of neurodevelopmental deficits among ECMO survivors remain largely unexplained.

Repair of interrupted aortic arch with an augmented aortic anastomosis

In cases of interrupted aortic arch type A, the end-to-end aortic anastomosis can be enlarged with a left subclavian flap. In type B interruption, the divided left carotid artery is anastomosed to the distal aorta, and the anastomosis can be augmented with a reversed left subclavian flap. These techniques provide a tension-free, much wider, and noncircumferential anastomosis with potential for growth. Using a combined lateral and anterior approach, the duration of circulatory arrest for the intracardiac repair is minimized.

Neurological findings in newborn infants after extracorporeal membrane oxygenation, with special reference to the EEG

Seventeen newborn infants were treated with extracorporeal membrane oxygenation (ECMO). Two died shortly after the start of ECMO due to the underlying disease, two died later in the course due to a lack of recovery of lung function and two others died weeks after ECMO from renal damage and a cardiac defect. Of the survivors, nine are developing normally (aged between one and four years) and two are severely disabled because of infarctions of the left hemisphere, acquired before and after ECMO. Intermittent-discontinuous EEGs did not indicate a poor prognosis if normalization of the EEG occurred within seven days. However, infarcted areas on ultrasonography, persistent EEG changes or deteriorating findings indicated disability or early death.

Utility of serial EEGs in neonates during extracorporeal membrane oxygenation

We found electroencephalographic (EEG) studies to be useful for monitoring cerebral function, for confirming seizure activity, and for limited prediction of short-term outcome in 145 neonates who required extra-corporeal membrane oxygenation (ECMO) of reversible respiratory failure. The EEG tracings were classified as normal or as mildly, moderately, or markedly abnormal; abnormal recordings were further classified as focal, diffuse, or predominantly lateralized. A significant decrease in frequency and degree of EEG abnormalities was observed in recordings obtained after ECMO compared to those obtained prior to (P = .001) or during ECMO (P = .001). There was no significant increase in marked EEG abnormalities when recordings obtained before and during ECMO were compared (P = 0.41). Of 11 infants with electrographic seizures during ECMO, 7 (64%) either died during their nursery courses or were developmentally handicapped at age 1 year which is a significantly greater adverse outcome than that observed in infants without EEG seizure activity (P less than .003). No consistently lateralized EEG abnormalities were observed during or after ECMO when compared to tracings obtained before cannulation of the right common carotid artery. There was no acute change in EEG rhythm or amplitude over the right cerebral hemisphere during right common carotid artery cannulation. Our observations support the value of serial EEG in the assessment of cerebral function in critically ill infants undergoing ECMO. They further suggest that, in this patient population, cannulation of the right common carotid artery is a safe procedure that does not result in lateralized abnormalities of cerebral electrical activity.

Neurodevelopmental outcome in neonates after extracorporeal membrane oxygenation: cranial magnetic resonance imaging and ultrasonography correlation

Irreversible ligation of the right common carotid artery and right internal jugular vein is usual in venoarterial extracorporeal membrane oxygenation (ECMO) for treatment of severe respiratory failure in neonates. Vessel ligation with ECMO may magnify risks of cerebral hemorrhage or infarction (CHI) and adversely affect neurodevelopmental outcome. To correlate CHI after ECMO with neurodevelopmental outcome, we reviewed cranial ultrasonography (US) and magnetic resonance imaging (MRI) scans in 22 consecutive neonatal ECMO survivors and compared these with results of Bayley Scales of Infant Development obtained at 3, 6, 12, and 24 months of follow-up. All patients had US, and 19 had MRI. No US or MRI had focal abnormal findings attributable to ECMO; specifically, there was no evidence of CHI. Two infants had generalized cerebral atrophy, and one of these had an abnormal Bayley examination. One infant with a normal MRI had a single right focal seizure 4 days after ECMO. Of 20 infants with Bayley developmental tests at 3 to 30 months of age (mental index range, 72 to 135; motor index range, 71 to 150), only 3 were abnormal. In our experience, the incidence of CHI secondary to ECMO is less than that reported. After ECMO, the absence of intracranial hemorrhage, cerebral infarct, or cerebral atrophy on US or MRI usually correlates with normal short-term neurodevelopmental outcome.

Significance of seizures associated with extracorporeal membrane oxygenation

We previously reported a predominance of left focal motor seizures in infants receiving extracorporeal membrane oxygenation (ECMO), raising concerns about possible ischemia resulting from the right common carotid artery ligation. We therefore evaluated the neurologic and psychologic outcome at 2 years of age of all infants with ECMO-related seizures. Although 8 of 12 infants had left focal seizures in infancy, there was no lateralization of motor findings at 2 years of age; left hemiparesis was present in three of the infants and right hemiparesis in three. The developmental quotient was normal in 6 of 12 infants, low-average in three, borderline in two, and in the mentally handicapped range in one. We conclude that any ischemia resulting from carotid ligation is not great enough to produce long-term lateralizing findings but that seizures during ECMO are a risk factor for later cerebral palsy or developmental delay.

Hidden mortality rate associated with extracorporeal membrane oxygenation

We reviewed the outcome of all infants referred to, and accepted in, our extracorporeal membrane oxygenation (ECMO) program during a 52-month period. One hundred sixty-seven referrals, representing 158 infants and nine mothers who had not yet delivered their infants, were accepted. Eighteen infants (11.3% of all neonates transported) died before leaving the referring hospital, during transport, or shortly after admission to our unit. Contraindications to ECMO excluded 17 (10.1%) of the 167 referrals. Sixty-two infants (37.1%) initially did not meet ECMO criteria. Two died before ECMO could be started. Sixty-eight infants (40.7%) were given ECMO therapy, and 11 died (16.1%). Nine mothers were referred because of fetal conditions that might require ECMO; of these infants, two died during delivery and three had contraindications to the use of ECMO. The four remaining infants were given ECMO therapy; three survived. The overall mortality rate was 27.5% (46/167); 18 (39.1%) of the 46 deaths were associated with transfer. The mortality rate associated with congenital diaphragmatic hernia was 63.6%. We recommend early transport of infants with this type of hernia during the postoperative "honeymoon" or during in utero transport with delivery at an ECMO center. We also recommend that infants with meconium aspiration syndrome be transported to an ECMO center when an oxygenation index of 25 is reached. The mortality rate associated with transport needs to be considered in evaluating ECMO programs. Earlier, expedited transfers may increase the survival rate.

Extracorporeal membrane oxygenation and indications for cardiopulmonary bypass in the neonate

Extracorporeal membrane oxygenation (ECMO) is a rescue technique used for term and near-term neonates who have respiratory failure that is unresponsive to conventional therapy. The complexity of the equipment necessitates intensive training of a specialized team before setting up an ECMO unit. An understanding of the physiology underlying ECMO and the criteria used for patient selection assists the nurse in identifying neonates who might benefit from the technique.

Long-term neurophysiologic outcome after neonatal extracorporeal membrane oxygenation

We examined clinical and neurophysiologic measures in 10 children 4 to 9 years after neonatal extracorporeal membrane oxygenation. Electroencephalograms did not correlate with clinical or other neurophysiologic measures of interhemispheric asymmetry. By ultrasound imaging, the right internal carotid artery velocity was approximately 62% of that on the left, and right internal carotid flow was reduced by 74% (p less than or equal to 0.01), whereas an age-matched control group showed no differences. A decrease in the amplitude of the long-latency auditory and somatosensory evoked potentials was noted over the right hemisphere after left-sided stimulation compared with the left hemispheric potentials after right-sided stimulation (p less than or equal to 0.005). No significant differences in hemispheric symmetry were noted in the amplitudes for wave V of the auditory brain-stem response or in the P30 component of the middle-latency auditory evoked potentials. Likewise, latency measures of the evoked potentials were symmetric. We conclude that (1) neonatal extracorporeal membrane oxygenation is associated with long-lasting decreased right internal carotid blood flow with compensatory increased flow through the left carotid system and (2) there is a consistent reduction in the amplitude of right hemispheric long-latency evoked potentials. These latter findings may reflect redirected cerebral blood flow patterns after extracorporeal membrane oxygenation.

Gas exchange in extracorporeal circuits for neonates: comparison of three different canulation systems during animal experiments

During twenty animal experiments the effectiveness of the gas exchange during extracorporeal membrane oxygenation (ECMO) was evaluated. Arteriovenous, venovenous and venoarterial perfusion systems were compared. While PO2 saturation values were sufficient in all three groups the PO2 values were significant higher during arteriovenous perfusion (84.22 +/- 3.5 mmHg) compared to venovenous 71.99 +/- 7.3 mmHg) and venoarterial (65.11 +/- 4.5 mmHg) perfusion (p less than 0.001). PCO2 values correlated with the flow in the extracorporeal circuit in all three groups. The absolute values of PCO2 were significantly lowest during venoarterial perfusion (39.68 +/- 3.1 mmHg) compared to the venovenous (42.69 +/- 3.3 mmHg) and the arteriovenous mode (49.96 +/- 4.1 mmHg). These results indicate that perfusion circuits other than the original venoarterial ECMO could provide sufficient gas transfer for respiratory insufficient neonates while avoiding points of criticism of such systems.