The effects of venous occlusion on cerebral blood flow characteristics during ECMO

Neuromonitoring During ECMO Support in Children

Extracorporeal membrane oxygenation is a potentially lifesaving intervention for children with severe cardiac or respiratory failure. It is used with increasing frequency and in increasingly more complex and severe diseases. Neurological injuries are important causes of morbidity and mortality in children treated with extracorporeal membrane oxygenation and include ischemic stroke, intracranial hemorrhage, hypoxic-ischemic injury, and seizures. In this review, we discuss the epidemiology and pathophysiology of neurological injury in patients supported with extracorporeal membrane oxygenation, and we review the current state of knowledge for available modalities of monitoring neurological function in these children. These include structural imaging with computed tomography and ultrasound, cerebral blood flow monitoring with near-infrared spectroscopy and transcranial Doppler ultrasound, and physiological monitoring with electroencephalography and plasma biomarkers. We highlight areas of need and emerging advances that will improve our understanding of neurological injury related to extracorporeal membrane oxygenation and help to reduce the burden of neurological sequelae in these children.

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.

A Scoping Review of Cerebral Doppler Arterial Waveforms in Infants

Cerebral Doppler ultrasound has been an important tool in pediatric diagnostics and prognostics for decades. Although the Doppler spectrum can provide detailed information on cerebral perfusion, the measured spectrum is often reduced to simple numerical parameters. To help pediatric clinicians recognize the visual characteristics of disease-associated Doppler spectra and identify possible areas for future research, a scoping review of primary studies on cerebral Doppler arterial waveforms in infants was performed. A systematic search in three online bibliographic databases yielded 4898 unique records. Among these, 179 studies included cerebral Doppler spectra for at least five infants below 1 y of age. The studies describe variations in the cerebral waveforms related to physiological changes (43%), pathology (62%) and medical interventions (40%). Characteristics were typically reported as resistance index (64%), peak systolic velocity (43%) or end-diastolic velocity (39%). Most studies focused on the anterior (59%) and middle (42%) cerebral arteries. Our review highlights the need for a more standardized terminology to describe cerebral velocity waveforms and for precise definitions of Doppler parameters. We provide a list of reporting variables that may facilitate unambiguous reports. Future studies may gain from combining multiple Doppler parameters to use more of the information encoded in the Doppler spectrum, investigating the full spectrum itself and using the possibilities for long-term monitoring with Doppler ultrasound.

Utility of cephalic drains in infants receiving extracorporeal membrane oxygenation

INTRODUCTION

The addition of cephalic drains (CDs) in extracorporeal membrane oxygenation (ECMO) to augment venous drainage may offer benefit, though their use is varied. Our objective was to describe our institution's experience with CDs including flow rates and patency. We also compared complication rates between patients with and without a CD.

METHODS

This retrospective cohort study included infants <12 months of age cannulated for ECMO between January 1, 2010 and September 30, 2019 at a single institution. Flow data were obtained for those with a CD. Demographic and complication rates were obtained for all.

RESULTS

Of 264 patients in the final cohort, 220 (83%) had a CD of which 93.2% remained patent to decannulation. CDs typically provided 30% or more of ECMO flow throughout the ECMO run. The median time to CD clot was 139 h (range 48-635 h). Patients with a clotted CD had longer ECMO runs than those whose CD remained patent (median 382 h [IQR 217-538] vs 139 h [IQR 91-246], p < 0.001). Survival to discharge was lower for those with clotted versus patent CD (14% vs 70%, p < 0.001). Mechanical complications were more common in patients with CD (p = 0.005). Seizures were more common in those without a CD (p = 0.021).

CONCLUSIONS

In this cohort, the majority of CDs placed remained patent at decannulation and provided substantial additional venous drainage. Mechanical problems were common in patients with CDs, but without clinical sequelae. Further study is warranted to elucidate CD impact on short- and long-term outcomes.

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.

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.

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.

Cerebrovascular Physiology During Pediatric Extracorporeal Membrane Oxygenation: A Multicenter Study Using Transcranial Doppler Ultrasonography

OBJECTIVES

To explore changes to expected, age-related transcranial Doppler ultrasound variables during pediatric extracorporeal membrane oxygenation.

DESIGN

Prospective, observational, multicenter study.

SETTING

Tertiary care PICUs.

PATIENTS

Children 1 day to 18 years old requiring veno arterial extracorporeal membrane oxygenation.

METHODS

Participants underwent daily transcranial Doppler ultrasound measurement of bilateral middle cerebral artery flow velocities. Acute neurologic injury was diagnosed if seizures, cerebral hemorrhage, or diffuse cerebral ischemia was detected.

MEASUREMENTS AND MAIN RESULTS

Fifty-two children were enrolled and analyzed. In the 44 children without acute neurologic injury, there was a significant reduction in systolic flow velocity and mean flow velocity compared with predicted values over time (F [8, 434] = 60.44; p ≤ 0.0001, and F [8, 434] = 17.61; p ≤ 0.0001). Middle cerebral artery systolic flow velocity was lower than predicted on extracorporeal membrane oxygenation days 1-5, and mean flow velocity was lower than predicted on extracorporeal membrane oxygenation days 1-3. In the six infants less than 90 days old suffering diffuse cerebral ischemia, middle cerebral artery systolic flow velocity, mean flow velocity, and diastolic flow velocity from extracorporeal membrane oxygenation days 1-9 were not significantly different when compared with children of similar age in the cohort that did not suffer acute neurologic injury (systolic flow velocity F [8, 52] = 0.6659; p = 0.07 and diastolic flow velocity F [8, 52] = 1.4; p = 0.21 and mean flow velocity F [8, 52] = 1.93; p = 0.07). Pulsatility index was higher in these infants over time than children of similar age in the cohort on extracorporeal membrane oxygenation that did not suffer acute neurologic injury (F [8, 52] = 3.1; p = 0.006). No patient in the study experienced cerebral hemorrhage.

CONCLUSIONS

Flow velocities in the middle cerebral arteries of children requiring extracorporeal membrane oxygenation are significantly lower than published normative values for critically ill, mechanically ventilated, sedated children. Significant differences in measured systolic flow velocity, diastolic flow velocity, and mean flow velocity were not identified in children suffering ischemic injury compared with those who did not. However, increased pulsatility index may be a marker for ischemic injury in young infants on extracorporeal membrane oxygenation.

Effects of an artificial placenta on brain development and injury in premature lambs

PURPOSE

We evaluated whether brain development continues and brain injury is prevented during Artificial Placenta (AP) support utilizing extracorporeal life support (ECLS).

METHODS

Lambs at EGA 118days (term=145; n=4) were placed on AP support (venovenous ECLS with jugular drainage and umbilical vein reinfusion) for 7days and sacrificed. Early (EGA 118; n=4) and late (EGA 127; n=4) mechanical ventilation (MV) lambs underwent conventional MV for up to 48h and were sacrificed, and early (n=5) and late (n=5) tissue control (TC) lambs were sacrificed at delivery. Brains were harvested, formalin-fixed, rehydrated, and studied by magnetic resonance imaging (MRI). The gyrification index (GI), a measure of cerebral folding complexity, was calculated for each brain. Diffusion-weighted imaging was used to determine fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in multiple structures to assess white matter (WM) integrity.

RESULTS

No intracranial hemorrhage was observed. GI was similar between AP and TC groups. ADC and FA did not differ between AP and late TC groups in any structure. Compared to late MV brains, AP brains demonstrated significantly higher ADC (0.45±0.08 vs. 0.27±0.11, p=0.02) and FA (0.61±0.04 vs. 0.44±0.05; p=0.006) in the cerebral peduncles.

CONCLUSIONS

After 7days of AP support, WM integrity is preserved relative to mechanical ventilation.

TYPE OF STUDY

Research study.

Cerebral Pathophysiology in Extracorporeal Membrane Oxygenation: Pitfalls in Daily Clinical Management

Extracorporeal membrane oxygenation (ECMO) is a life-saving technique that is widely being used in centers throughout the world. However, there is a paucity of literature surrounding the mechanisms affecting cerebral physiology while on ECMO. Studies have shown alterations in cerebral blood flow characteristics and subsequently autoregulation. Furthermore, the mechanical aspects of the ECMO circuit itself may affect cerebral circulation. The nature of these physiological/pathophysiological changes can lead to profound neurological complications. This review aims at describing the changes to normal cerebral autoregulation during ECMO, illustrating the various neuromonitoring tools available to assess markers of cerebral autoregulation, and finally discussing potential neurological complications that are associated with ECMO.

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.

Extracorporeal membrane oxygenation and cerebral blood flow velocity in children

OBJECTIVE

To determine how extracorporeal membrane oxygenation affects cerebral blood flow velocity and to determine whether specific changes in cerebral blood flow velocity may be associated with neurologic injury.

DESIGN

Prospective, observational study.

SETTING

PICU in a tertiary care academic center.

PATIENTS

Children (age less than or equal to 18 yr) requiring extracorporeal membrane oxygenation support.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eighteen patients (age 3.8 ± 7.2 years; venovenous neck, n = 5; venoarterial neck, n = 8; venoarterial chest, n = 5) requiring extracorporeal membrane oxygenation underwent daily transcranial Doppler ultrasound measurements of cerebral blood flow velocity in bilateral middle cerebral arteries. Cerebral blood flow velocity measurements were recorded as a percentage of age and gender normal value. On extracorporeal membrane oxygenation, cerebral blood flow velocities in patients not suffering clinically evident neurologic injury were decreased with systolic flow velocity (Vs) 54% ± 3% predicted and mean flow velocity (Vm) 52% ± 4% predicted. After decannulation, Vs and Vm were higher than while on extracorporeal membrane oxygenation at 73% ± 3% predicted (p = 0.0007 vs. value on extracorporeal membrane oxygenation) and 64% ± 4% predicted (p = 0.01 vs. value on extracorporeal membrane oxygenation).Patients who developed clinically evident cerebral hemorrhage had higher Vs, diastolic flow velocity (Vd), and Vm compared with those who did not: 123% ± 8% predicted, 130% ± 18% predicted, 127% ± 9% predicted (p < compared to values in children not suffering neurological injury). Supranormal flow velocities were noted 2-6 days before clinical recognition of cerebral hemorrhage in all four patients. There were no significant differences in mean arterial blood pressure, circuit flow, or hematocrit between the children who suffered cerebral hemorrhage and those who did not. Partial pressure of carbon dioxide was lower in the group of patients who experienced cerebral hemorrhage than in those who did not (38 ± 2 vs. 44 ± 1 mm Hg, p = 0.03).

CONCLUSION

In children who did not suffer clinically apparent neurologic injury, cerebral blood flow velocities were lower than normal while on extracorporeal membrane oxygenation support and increased after decannulation. However, children who developed cerebral hemorrhage had higher than normal cerebral blood flow velocities noted for days prior to clinical recognition of bleeding. Cerebral blood flow velocity measurement may represent a portable, noninvasive way to predict cerebral complications of extracorporeal membrane oxygenation and deserves further study.

Altered cerebrovascular responses after exposure to venoarterial extracorporeal membrane oxygenation: role of the nitric oxide pathway

BACKGROUND

Previous studies in our laboratory on newborn lambs have shown cerebral autoregulation impairment after exposure to venoarterial extracorporeal membrane oxygenation (VA ECMO), with additional studies showing an altered cerebrovascular response to NG-nitro-L-arginine methyl ester in lamb cerebral vessels in this same model.

OBJECTIVE

To further study the mechanisms involved in altered cerebrovascular responses in vessels exposed to VA ECMO.

DESIGN

Prospective study.

SETTING

Research Animal Facility at Children's National Medical Center, Washington, DC.

SUBJECT

Newborn lambs, 1-7 days of age, 4.76 +/- 0.8 kg (n = 10).

METHODS

Animals randomly assigned two groups, control and VA ECMO, were anesthetized, ventilated, heparinized, and kept in a normal physiologic condition. Control animals were continued on ventilatory support, whereas animals in the VA ECMO groups were placed on VA ECMO, with bypass flows maintained between 120 and 200 mL x kg x min(-1) for 2.5 hrs. Isolated third-order branches of the middle cerebral arteries were studied for myotonic reactivity to increasing intraluminal pressure changes, response to acetylcholine, an endothelium-dependent vasodilator, 3-morpholinyl-sydnoneimine chloride, an endothelium-independent vasodilator, and serotonin, a direct vascular vasoconstrictor. Arterial caliber was monitored using video microscopy.

RESULTS

Myogenic constriction response was significantly decreased in the VA ECMO group compared with the control group (p = .03). Intraluminal acetylcholine caused concentration-dependent arterial dilation in the control group, whereas it resulted in vasoconstriction in the VA ECMO group (p = .008). There were no significant differences in dilation responses to 3-morpholinyl-sydnoneimine chloride and contractile responses to serotonin among the groups.

CONCLUSION

Cerebral arteries exposed to VA ECMO had impaired myogenic responses combined with altered endothelial function. The endothelial alteration seems to be mediated through the nitric oxide pathway, with recovery noted after addition of a nitric oxide donor. It can be postulated that these changes may reflect the mechanisms for the impairment of cerebral autoregulation previously reported in this lamb model.

Quantitative Electroencephalography Values of Neonates During and After Venoarterial Extracorporeal Membrane Oxygenation and Permanent Ligation of Right Common Carotid Artery

Venoarterial extracorporeal membrane oxygenation (ECMO) in neonates commonly needs neck vessel cannulation leading to ligation of right common carotid artery (RCCA) in some cases. Quantitative electroencephalography (EEG) measurements provide reproducible data of cerebral function. The aim of this case-control study was to test whether ligation of the RCCA results in EEG changes after ECMO weaning. Ten mechanically ventilated neonates not treated with ECMO were eligible as control patients. Seven ECMO patients receiving similar sedoanalgesia were investigated during and after ECMO and RCCA ligation. Dominant frequency, absolute alpha, theta, delta, and total powers of right and left frontocentral and temporooccipital derivations were calculated. Dominant frequency did not differ among groups. Power was found to be significantly decreased in all frequency bands during ECMO. After weaning from ECMO, EEG differences between the ECMO and control groups disappeared in spite of permanent RCCA ligation. It is concluded that ligation of the RCCA per se does not result in quantitative EEG changes.

Neonatal ECMO: neuroimaging and neurodevelopmental outcome

Intracranial injury continues to be a major complication associated with extracorporeal membrane oxygenation (ECMO)-treated neonates. The reported frequency of abnormal neuroimaging has ranged from 28% to 52%, depending on neuroimaging techniques and methods of classification. The purpose of this chapter is to describe types of imaging techniques commonly used to evaluate the ECMO neonate, to specify different types of injuries that have been reported, and to identify factors which increase the risk of injury. We will then describe the functional impact at age 5 years following neonatal brain injury among ECMO infants.

Venovenous extracorporeal membrane oxygenation in neonatal respiratory failure: does routine, cephalad jugular drainage improve outcome?

BACKGROUND/PURPOSE

Extracorporeal membrane oxygenation (ECMO), may be life saving for infants with severe respiratory failure, and when possible, veno-venous bypass through a jugular double lumen cannula, can be expected to provide satisfactory support for most patients. Some ECMO centers favor routine placement of a cephalad jugular cannula for the theoretical benefits of augmented (desaturated) venous return, reduction of atrial recirculation, and cerebral venous decompression. The purpose of this study was to querie the ELSO registry for patients who had undergone VV-ECMO and compare outcomes for patients with a double lumen cannula only (VVDL), with those who had both a double lumen and cephalad jugular cannula (VVDL + V).

METHODS

With institutional review board (IRB) approval, the Extracorporeal Life Support Organization (ELSO) registry (Ann Arbor, MI) was queried from January 1, 1989 to December 31, 2001, and all "neonatal respiratory" patients undergoing VV-ECMO via either the VVDL or VVDL + V modes were identified. Group comparisons by age, diagnosis, hours on bypass, mean flow rates (Q) at 4 and 24 hours, mean airway pressures (MAP) at initiation and at 24 hours of bypass, complications (including neurologic and cannula-specific), need for conversion to veno-arterial (VA) ECMO, and survival were performed. A similar analysis was performed on a congenital diaphragmatic hernia (CDH) patient subgroup. Student's t tests were used to compare means between groups, with P values of less than.05 considered significant.

RESULTS

The querie generated a total of 2,471 patients: 2,379 (96.3%) VVDL, and 92 (3.7%) VVDL + V. The groups were comparable with the only significant differences being a higher mean airway pressure at 24 hours of bypass and a more frequent use of inotropes during extracorporeal life support (ECLS) in the VVDL + V group. Comparison of a CDH patient subset (280 from the VVDL group and 25 from the VVDL + V group) showed the following significant differences: more frequent use of inotropes, higher MAP at 24 hours, and higher mean flow rates at 4 and 24 hours, all in the VVDL + V group. Patient outcomes, including survival, complications, and rates of conversion to VA bypass were comparable between like groups.

CONCLUSIONS

The theoretical benefits of routine placement of a cephalad jugular cannula during VV-ECMO via a jugular double lumen cannula are not substantiated by critical analysis of ELSO data.

Primary use of the venovenous approach for extracorporeal membrane oxygenation in pediatric acute respiratory failure

OBJECTIVES

To describe a single center's experience with the primary use of venovenous cannulation for supporting pediatric acute respiratory failure patients with extracorporeal membrane oxygenation (ECMO).

DESIGN

Retrospective chart review of all patients receiving extracorporeal life support at a single institution.

SETTING

Pediatric intensive care unit at a tertiary care children's hospital.

PATIENTS

Eighty-two patients between the ages of 2 wks and 18 yrs with severe acute respiratory failure.

INTERVENTIONS

ECMO for acute respiratory failure.

MEASUREMENTS AND MAIN RESULTS

From January 1991 until April 2002, 82 pediatric patients with acute respiratory failure were cannulated for ECMO support. Median duration of ventilation before ECMO was 5 days (range, 1-17 days). Sixty-eight of these patients (82%) initially were placed on venovenous ECMO. Fourteen patients were initiated and remained on venoarterial support, including six in whom venovenous cannulae could not be placed. One patient was converted from venovenous to venoarterial support due to inadequate oxygenation. Venoarterial patients had significantly greater alveolar-arterial oxygen gradients and lower PaO(2)/FIO(2) ratios than venovenous patients (p <.03). Fifty-five of 81 venovenous patients received additional drainage cannulae (46 of 55 with an internal jugular cephalad catheter). Thirty-five percent of venovenous patients and 36% of venoarterial patients required at least one vasopressor infusion at time of cannulation (p = nonsignificant); vasopressor dependence decreased over the course of ECMO in both groups. Median duration on venovenous ECMO for acute hypoxemic respiratory failure was 218 hrs (range, 24-921). Venovenous ECMO survivors remained cannulated for significantly shorter time than nonsurvivors did (median, 212 vs. 350 hrs; p =.04). Sixty-three of 82 ECMO (77%) patients survived to discharge-56 of 68 venovenous ECMO (81%) and nine of 14 venoarterial ECMO (64%).

CONCLUSIONS

Venovenous ECMO can effectively provide adequate oxygenation for pediatric patients with severe acute respiratory failure receiving ECMO support. Additional cannulae placed at the initiation of venovenous ECMO could be beneficial in achieving flow rates necessary for adequate oxygenation and lung rest.

Predictors of intracranial hemorrhage during neonatal extracorporeal membrane oxygenation

OBJECTIVE

To identify independent predictors of intracranial hemorrhage (ICH) during neonatal extracorporeal membrane oxygenation (ECMO).

STUDY DESIGN

This retrospective cohort consisted of all neonates who did not have an ICH before treatment with ECMO identified in the Extracorporeal Life Support Organization Registry from 1992 to 1995 (n = 4550). Multiple logistic regression analysis was used to identify factors independently correlated with ICH and to develop a model that could be used to predict the risk of ICH in neonates treated with ECMO.

RESULTS

ICH was identified in 9.9% of patients. The factors associated with ICH remaining after adjusting for other significant variables (P <.01) were gestational age (GA) <34 weeks (odds ratio [OR] 12.1, 95% confidence intervals [CI] [6.6, 22]), GA 34 to <36 weeks (OR 4.1, CI [2.9, 5.8]), GA 36 to <38 weeks (OR 2.1, CI [1.6, 2.8]) primary diagnosis of sepsis (OR 1.8, CI [1.4, 2.3]), epinephrine use (OR 1.9, CI [1.5, 2.5]), coagulopathy (OR 1. 6, CI [1.1, 2.2]), arterial pH <7.0 (OR 2.5, CI [1.6, 3.9]), and arterial pH 7.0 to <7.2 (OR 1.8 CI [1.3, 2.5]). ICH rates for neonates receiving venovenous versus venoarterial ECMO and for those treated with or without cephalic jugular venous drainage were not significantly different.

CONCLUSIONS

Gestational age, acidosis, sepsis, coagulopathy, and treatment with epinephrine are major independent factors associated with ICH in neonates treated with ECMO. In particular, GA <34 weeks remains a major barrier for use of current ECMO technologies.