ECMO in evolution: the impact of changing patient demographics and alternative therapies on ECMO

Risk Factors for Brain Injury in Newborns Treated with Extracorporeal Membrane Oxygenation

OBJECTIVE

This study aimed to assess the association of clinical risk factors with severity of magnetic resonance imaging (MRI) brain injury in neonatal extracorporeal membrane oxygenation (ECMO) patients.

STUDY DESIGN

This is a single-center retrospective study conducted at an outborn level IV neonatal intensive care unit in a free-standing academic children's hospital. Clinical and MRI data from neonates treated with ECMO between 2005 and 2015 were reviewed. MRI injury was graded by two radiologists according to a modified scoring system that assesses parenchymal injury, extra-axial hemorrhage, and cerebrospinal fluid spaces. MRI severity was classified as none (score = 0), mild/moderate (score = 1-13.5), and severe (score ≥ 14). The relationship between selected risk factors and MRI severity was assessed by Chi-square, analysis of variance, and Kruskal-Wallis tests where appropriate. Combinative predictive ability of significant risk factors was assessed by logistic regression analyses.

RESULTS

MRI data were assessed in 81 neonates treated with ECMO. Veno-arterial (VA) patients had more severe injury compared with veno-venous patients. There was a trend toward less severe injury over time. After controlling for covariates, duration of ECMO remained significantly associated with brain injury, and the risk for severe injury was significantly increased in patients on ECMO beyond 210 hours.

CONCLUSION

Risk for brain injury is increased with VA ECMO and with longer duration of ECMO. Improvements in care may be leading to decreasing incidence of brain injury in neonatal ECMO patients.

KEY POINTS

· Veno-arterial ECMO is associated with more brain injury by MRI compared with veno-venous ECMO.. · Longer duration of ECMO is significantly associated with severe brain injury by MRI.. · Risk for neurologic injury may be decreasing over time with advances in neonatal ECMO..

In-Hospital Outcomes Following Extracorporeal Membrane Oxygenation in a Retrospective Cohort of Infants

Objective

We sought to characterize associations between infant characteristics and extracorporeal membrane oxygenation (ECMO) survival using electronic health records data.

Study Design

We examined a cohort study of infants ≥32 weeks of gestational age and ≥1,800 g birth weight supported with ECMO in a Pediatrix Medical Group neonatal intensive care unit from 1998 to 2013.

Results

We identified 268 infants, of which 45 (17%) were <37 weeks of gestational age. Survival to discharge was 87% but was lower in premature compared with term infants (76 vs. 89%, p = 0.03). In multivariable analysis, acute kidney injury (odds ratio [OR] = 4.00; 95% confidence interval [CI] = 1.05, 15.24), postnatal age at cannulation of 7 to 13 days (OR = 5.86; 95% CI = 1.21, 28.44), and venoarterial ECMO cannulation (OR = 4.33; 95% CI = 1.77, 10.60) were associated with lower survival.

Conclusion

ECMO cannulation type, postnatal age, and acute kidney injury were associated with lower ECMO survival, while prematurity was not. Future studies are needed to identify risk factors and strategies to improve outcomes.

Venoarterial versus venovenous ECMO for neonatal respiratory failure

Extracorporeal membrane oxygenation (ECMO) continues to be an important rescue therapy for newborns with a variety of causes of cardio-respiratory failure unresponsive to high-frequency ventilation, surfactant replacement, and inhaled nitric oxide. There are approximately 800 neonatal respiratory ECMO cases reported annually to the Extracorporeal Life Support Organization; venoarterial ECMO has been used in approximately 72% with a cumulative survival of 71% and venovenous has been used in 28% with a survival of 84%. Congenital diaphragmatic hernia is now the most common indication for ECMO. This article reviews the development of the two types of extracorporeal support, venoarterial and venovenous ECMO, and discusses the advantages of each method, the current selection criteria, the procedure, and the clinical management of neonates on ECMO.

The impact of ethnic population dynamics on neonatal ECMO outcomes: a single urban institutional study

INTRODUCTION

Neonatal extracorporeal membrane oxygenation ECMO has been clinically used for the last 25 y. It has been an effective tool for both cardiac and non cardiac conditions. The impact of ethno-demographic changes on ECMO outcomes however remains unknown. We evaluated a single institution's experience with non cardiac neonatal ECMO over a 28-y period.

METHODS

A retrospective review of all neonates undergoing noncardiac ECMO between the y 1984 and 2011 was conducted and stratified into year groups I, II, III (≤1990, 1991-2000, and ≥2001). Demographic, clinical, and outcome data were collected. The patient specifics, ECMO type, ECMO length, blood use, complications, and outcomes were analyzed. Univariate, bivariate, and multivariate analyses were then performed.

RESULTS

Data was available for 827 patients. The number of African-American and Hispanic patients increased over the last 27 y (27.5% versus 45.0% and 3.3% versus 21.5%, year group I versus year group III, respectively). The proportion of congenital diaphragmatic hernia (CDH) patients by ethnicity also increased for African-Americans and Hispanics between the two year groups (22.0% to 33.0% and 4.9% to 33.0%, respectively). Similar pattern was noted for non-CDH diagnoses. Low birth weight, low APGAR scores, CDH, primary pulmonary hypertension, central nervous system hemorrhage, and ECMO were independent predictors of mortality. Ethnicity, in itself however, was not associated with mortality on adjusted analysis.

CONCLUSION

More African-Americans and Hispanics have required ECMO over the years with a concurrent decrease in the number of Caucasians. While ethnicity was not an independent predictor of mortality, it appears to be a surrogate for fatal but sometime preventable diagnoses among minorities. Further investigations are needed to better delineate the reason behind this disparity.

Factors associated with survival in pediatric extracorporeal membrane oxygenation--a single-center experience

AIM

We aimed to examine outcomes of extracorporeal membrane oxygenation (ECMO) therapy in the pediatric population and identify pre-ECMO and on-ECMO characteristics that are associated with survival.

METHODS

We retrospectively reviewed the ECMO records at our institution between 1999 and 2008 and selected pediatric patients who were cannulated for respiratory failure or hemodynamic instability resistant to conventional interventions. We recorded details of pre-ECMO clinical characteristics, including blood gas variables and mechanical ventilatory support, and details of ECMO therapy including survival off ECMO and to hospital discharge. Predictors of survival were analyzed using logistic regression modeling and a prediction algorithm was developed.

RESULTS

Of the 445 ECMO runs, data from 58 consecutive patients were analyzed: 57% were successfully decannulated, and 48% survived to discharge from the hospital. The cohort included 32 (55%) female patients, 22 postoperative patients (38%), and 15 (26%) with an immunosuppressive condition, with a median age of 5 years and weight 19.5 kg, The mean duration of pre-ECMO respiratory support was 3 days, in the form of high-frequency oscillatory ventilation (n = 28, 48%) and conventional mechanical ventilation (n = 13, 22%). The median duration (interquartile range) of ECMO support was 142 hours (60, 321) or 5.9 days. Pre-ECMO pH above 7.2 (P < .001) and oxygenation index below 35 (P = .021) were associated with the highest survival rates. Pre-ECMO PaCO(2) and duration of mechanical ventilation were not associated with survival.

CONCLUSIONS

Based on our results, ECMO therapy should be considered early in children with oxygenation index greater than 35 with worsening metabolic status. The restriction of ECMO based on ventilator days alone needs to be revisited in this era of lung protective ventilation.

Medical and financial impact of a neonatal extracorporeal membrane oxygenation referral center in the nitric oxide era

OBJECTIVES

The primary objective of this study was to determine whether widespread use of nitric oxide after Food and Drug Administration approval decreased admissions to a neonatal referral center for extracorporeal membrane oxygenation evaluation. We also sought to determine whether antecedent treatment delayed eventual transfer, resulting in sicker patients, increased mortality, increased extracorporeal membrane oxygenation application, and higher direct costs of care.

METHODS

This was a retrospective cohort study of all of the patients transferred to a neonatal referral center for extracorporeal membrane oxygenation evaluation before (1995-1999) and after (2000-2005) Food and Drug Administration approval of nitric oxide. Patients were divided into "congenital diaphragmatic hernia" and "persistent pulmonary hypertension" (all other diagnoses) for additional analysis.

RESULTS

Admission rates for extracorporeal membrane oxygenation evaluation decreased in the nitric oxide era, and eventual transfer was not delayed. Persistent pulmonary hypertension patients had improved oxygen indexes, a trend toward decreased mortality, decreased extracorporeal membrane oxygenation use, and decreased direct costs. Congenital diaphragmatic hernia patients had unchanged physiologic measurements, mortality, and extracorporeal membrane oxygenation use with increased direct costs of care. As a whole, outcomes for patients transferred for extracorporeal membrane oxygenation evaluation improved, whereas direct costs were unchanged.

CONCLUSIONS

Persistent pulmonary hypertension patients had improved outcomes with decreased costs, whereas congenital diaphragmatic hernia patients had unchanged outcomes with increased costs. Overall, patients admitted to this NICU because of the presence of extracorporeal membrane oxygenation services had improved outcomes without increased costs in the nitric oxide era.

Oxygenation index for extracorporeal membrane oxygenation: is there predictive significance?

Although extracorporeal membrane oxygenation (ECMO) is known to improve survival in neonates with respiratory failure, there has been a significant decrease in the use of ECMO in recent years. Alternative modalities such as high-frequency oscillatory ventilation (HFOV), inhaled nitric oxide (iNO), and surfactant therapy are associated with this decline. The criteria for the initiation of ECMO, developed about 20 years ago, are likely no longer relevant. We examined the predictive significance of the oxygenation index (OI) as a patient entry criterion for ECMO use. We sought a critical OI level predicting death or chronic lung disease (CLD) with and without ECMO use. We also examined whether patients with certain OIs are more likely to have worse outcomes. One hundred and seventy-four term-newborn admissions between 1995 and 2000 requiring mechanical ventilation were enrolled in the study. Receiver operating curve analysis was performed to find a cutoff value of OI for ECMO initiation. Mortality rates and CLD probability were compared to the worst OIs. Our 6-year ECMO administration experience showed that an OI of 33.2 is a suitable cutoff value for ECMO initiation with high sensitivity and specificity as a predictive criterion. The critical OI value associated with the CLD risk when ECMO is not used is in the 40s. OI is a good predictor of CLD; the probability of CLD increases with higher OIs. Our data support the trend toward the use of new interventions over ECMO, especially for patients with OI scores of less than 33.2. Only when the probability of ventilator-associated lung injury becomes significant is it better to consider ECMO than conventional modalities.

Neonatal ECMO: Current controversies and trends

Extracorporeal membrane oxygenation (ECMO), a technique for providing life support to patients with cardiac and/or respiratory dysfunction, allows the heart and lungs to "rest." The neonatal respiratory population has been a major benefactor of ECMO since 1982. Its use for neonatal respiratory disease increased dramatically until the past few years, when the number of neonatal respiratory ECMO cases began a downward trend. Fewer patients with persistent pulmonary hypertension of the newborn (PPHN), meconium aspiration syndrome, respiratory distress syndrome, or sepsis are requiring ECMO support as frequently as in the past. Many attribute this decline to the newer respiratory therapies-mainly, surfactant, high-frequency oscillatory ventilation, and inhaled nitric oxide. Neonates who continue to require ECMO today are sicker than the historic norm and have more complicated and lengthy ECMO runs. Patients with congenital diaphragmatic hernia, PPHN, and sepsis remain the most consistent in their representation among ECMO recipients within this author's institution, suggesting that the newer respiratory therapies have not had the same impact on these patients' needs for ECMO support. Better guidelines for determining which patients would benefit from earlier inititation of ECMO are needed.

Neonatal extracorporeal life support: impact of new therapies on survival

OBJECTIVE

To evaluate the effects of pre-extracorporeal life support (ECLS) management with nitric oxide (NO), high frequency ventilation (HFV), and surfactant on mortality among neonates supported with ECLS.

STUDY DESIGN

Extracorporeal Life Support Organization (ELSO) data on 7017 neonates cannulated for respiratory reasons between 1996 and 2003 were analyzed using chi2, analysis of variance, and logistic regression.

RESULTS

The use of ECLS declined by 26.6% over the study period with no significant change in mortality. Unadjusted ECLS mortality for NO-treated patients was lower than for infants not treated with NO (25.1% vs 28.6%, P = .0012) and for infants treated with surfactant than for infants not treated with surfactant (18.7% vs 30.3%, p <.0001.) Unadjusted mortality for HFV-treated patients was no different than for non-HFV-treated patients (26.0% vs 26.6%, P = .56). After adjusting for confounders (primary diagnosis, age at cannulation, ECMO year 1996-1999 vs 2000-2003), surfactant use was associated with decreased mortality. NO-treated neonates were less likely to have a pre-ECLS cardiopulmonary arrest than infants not treated with NO. NO, HFV, and surfactant were not associated with prolongation of ECLS or mechanical ventilation.

CONCLUSIONS

NO, HFV, and surfactant were not associated with increased mortality in neonates who require ECLS for hypoxic respiratory failure.

The role of neonatal networks

A neonatal network is a collaboration involving more than one clinical site where a common protocol is used for a randomized trial, observational study, or quality improvement project. Because the prevalence of important outcomes (e.g., death or neurodevelopmental impairment) is low among neonates, multi-site studies have been an essential contributor to the identification of interventions for improving the health of neonates. In this review we summarize key aspects of the conduct of multi-site studies and describe some of the prominent accomplishments and contributions of neonatal networks. Important contributions of randomized trials and observational studies include the identification, and assessment, of potential strategies for prevention of cerebral palsy, chronic lung disease, and blindness due to retinopathy of prematurity. In addition, quality improvement projects by neonatal networks have greatly facilitated the dissemination of information about, and implementation of, evidence-based interventions.

Extracorporeal membrane oxygenation in infants with meconium aspiration syndrome: a decade of experience with venovenous ECMO

BACKGROUND

Despite the emergence of new therapies for respiratory failure of the newborn with meconium aspiration syndrome (MAS), extracorporeal membrane oxygenation (ECMO) has a significant role as a rescue modality in these infants. Our objective was to compare the use of venovenous (VV) vs venoarterial (VA) ECMO in newborns with MAS who need ECMO and to ascertain the impact of new therapies in these infants during the last decade. We also evaluated how disease severity or time of ECMO initiation affected mortality and morbidity.

METHODS

A report of 12 years experience (1990-2002) of a single center, comparing VV and VA ECMO, is given. Venovenous ECMO was the preferred rescue modality for respiratory failure unresponsive to maximal medical therapy. Venoarterial ECMO was used only when the placement of a VV ECMO 14-F catheter was not possible; 128 patients met ECMO criteria, 114 were treated with VV ECMO, and 12 with VA ECMO. Two patients were converted from VV to VA ECMO.

RESULTS

Venovenous and VA ECMO patients had comparable birth weight (mean +/- SEM, 3.48 +/- 0.05 vs 3.35 +/- 0.15 kg) and gestational age (40.3 +/- 0.1 vs 40.7 +/- 0.3 weeks). Before ECMO, there was no difference between VV and VA ECMO patients in oxygenation index (60 +/- 3 vs 63 +/- 8), mean airway pressure (19.5 +/- 0.4 vs 20.8 +/- 1.5 cm H2O), alveolar-arterial O2 gradient (630 +/- 2 vs 632 +/- 4 torr), ECMO cannulation age (median [25th-75th percentiles], 23 [14-47] vs 26 [14-123] hours), or in the % of patients who needed vasopressors/inotropes (98% vs 100%). From November 1994, inhaled nitric oxide (NO) was available. Before VV ECMO, 67% of the patients received NO, 24% received surfactant, and 48% were treated with high-frequency ventilation (HFV). There was no significant difference between VV and VA ECMO patients in survival rate (94% vs 92%), ECMO duration (88 [64-116] vs 94 [55-130] hours), time of extubation (9 [7-11] vs 14 [9-15] days), age at discharge (23 [18-30] vs 27 [15-41] days), or incidence of short-term intracranial complications (5.3% vs 16.7%). For the total cohort of 126 infants, indices of disease severity (oxygenation index, alveolar-arterial O 2 gradient, mean airway pressure) did not correlate with outcome measures. Delay in ECMO initiation (> 96 hours) was associated with prolonged mechanical ventilation and hospitalization (P < .01). New therapies (NO, HFV, surfactant) in the second part of the decade were associated with a longer ECMO duration (98 [80-131] vs 87 [60-116] hours; P < .05), no delay in ECMO initiation time (23 [10-40] vs 24 [14-52] hours), and no significant change in survival (97% vs 92.5%). No patient was treated with VA ECMO after 1994.

CONCLUSIONS

Venovenous ECMO is as reliable as VA ECMO in newborns with MAS in severe respiratory failure who need ECMO. Delay in ECMO initiation may result in prolonged mechanical ventilation and increased length of hospital stay. The emergence of new conventional therapies (NO, HFV, surfactant) and particularly increased experience enable sole use of VV ECMO with no significant change in survival in infants with MAS.

ECMO for neonatal respiratory failure

Extracorporeal membrane oxygenation (ECMO) has been offered as a life-saving technology to newborns with respiratory and cardiac failure refractory to maximal medical therapy. ECMO has been used in treatment of neonates with a variety of cardio-respiratory problems, including meconium aspiration syndrome (MAS), persistent pulmonary hypertension of the neonate (PPHN), congenital diaphragmatic hernia (CDH), sepsis/pneumonia, respiratory distress syndrome (RDS), air leak syndrome, and cardiac anomalies. For this group of high-risk neonates with an anticipated mortality rate of 80% to 85%, ECMO has an overall survival rate of 84%, with recent data showing nearly 100% survival in many diagnostic groups. This article reviews the current selection criteria for ECMO and the clinical management of neonates on ECMO, and discusses the long-term outcome of neonates treated with ECMO.

Surfactant Therapy for Meconium Aspiration Syndrome

Meconium aspiration syndrome (MAS) is an important cause of respiratory distress in the term infant. Therapy for the disease remains problematic, and newer treatments such as high-frequency ventilation and inhaled nitric oxide are being applied with increasing frequency. There is a significant disturbance of the pulmonary surfactant system in MAS, with a wealth of experimental data indicating that inhibition of surfactant function in the alveolar space is an important element of the pathophysiology of the disease. This inhibition may be mediated by meconium, plasma proteins, haemoglobin and oedema fluid, and, at least in vitro, can be overcome by increasing surfactant phospholipid concentration. These observations have served as the rationale for administration of exogenous surfactant preparations in MAS, initially as standard bolus therapy and, more recently, in association with therapeutic lung lavage. Bolus surfactant therapy in ventilated infants with MAS has been found to improve oxygenation in most studies, although there are a significant proportion of nonresponders and in many cases the effect is transient. Pooled data from randomised controlled trials of surfactant therapy suggest a benefit in terms of a reduction in the requirement for extracorporeal membrane oxygenation (relative risk 0.48 in surfactant-treated infants) but no diminution of air leak or ventilator days. Current evidence would support the use of bolus surfactant therapy on a case by case basis in nurseries with a relatively high mortality associated with MAS, or the lack of availability of other forms of respiratory support such as high-frequency ventilation or nitric oxide. If used, bolus surfactant should be administered as early as practicable to infants who exhibit significant parenchymal disease, at a phospholipid dose of at least 100 mg/kg, rapidly instilled into the trachea. Natural surfactant or a third-generation synthetic surfactant should be used and the dosage repeated every 6 hours until oxygenation has improved. Lung lavage with dilute surfactant has recently emerged as an alternative to bolus therapy in MAS, which has the advantage of removing surfactant inhibitors from the alveolar space in addition to augmenting surfactant phospholipid concentration. Combined animal and human data suggest that lung lavage can remove significant amounts of meconium and alveolar debris, and thereby improve oxygenation and pulmonary mechanics. Arterial oxygen saturation inevitably falls during lavage but has been noted to recover relatively rapidly, even in infants with severe disease. Several randomised controlled trials of surfactant lavage in MAS are underway, and until the results are known, lavage must be considered an unproven and experimental therapy.

Utilization and outcomes of neonatal cardiac extracorporeal life support: 1996-2000

OBJECTIVES

Extracorporeal life support for neonatal respiratory failure has decreased, but utilization and outcome of cardiac extracorporeal life support are not well characterized. Among neonates born 1996-2000, our objects were to evaluate changes in utilization and outcome of cardiac extracorporeal life support and characterize correlates of survival.

DESIGN

Retrospective analysis of Extracorporeal Life Support Organization Registry data.

SETTING

Intensive care units participating in the ELSO registry.

PATIENTS

Patients placed on extracorporeal life support for center-specified "cardiac support" at </=30 days of age from 1996 to 2000. Patients with hypoplastic left heart syndrome were also analyzed separately.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient characteristics and correlates of survival to discharge or transfer were analyzed by chi-square, Student's t-test, and logistic regression analysis. Neonates placed on cardiac extracorporeal life support increased from 112 in 1996 to 200 in 2000 (total n = 740). Overall survival was 34.2%: 28% for hypoplastic left heart syndrome and 35.4% for nonhypoplastic left heart syndrome. For the overall group, no significant correlations were found between survival and year on extracorporeal life support, multiple runs, or diagnosis of hypoplastic left heart syndrome. Diagnoses of transposition of the great arteries (p = .03) or persistent pulmonary hypertension of the neonate (p = .004) and extracorporeal life support at <3 days (p = .003) were associated with higher survival. Survivors had fewer mean extracorporeal life support hours (125.5 +/- 121.4 vs. 159.0 +/- 127.6, p = .0006). Logistic regression confirmed significant bivariate findings. A total of 118 hypoplastic left heart syndrome patients were reported from 1996 to 2000. Extracorporeal life support at >15 days was associated with improved survival among hypoplastic left heart syndrome patients (p = .03), and survivors had fewer mean extracorporeal life support hours (89.3 +/- 52.3 vs. 147.5 +/- 129.7, p = .015). Logistic regression showed that only greater number of hours on extracorporeal life support was independently associated with nonsurvival.

CONCLUSIONS

Neonatal cardiac extracorporeal life support use increased substantially from 1996 to 2000, with survival to discharge or transfer in more than one third of patients. Hypoplastic left heart syndrome was not associated with nonsurvival. Fewer hours on extracorporeal life support, diagnoses of persistent pulmonary hypertension of the neonate and transposition of the great arteries, and extracorporeal life support at <3 days were associated with survival.

Intracranial hemorrhage in premature neonates treated with extracorporeal membrane oxygenation correlates with conceptional age

OBJECTIVE

To determine the effect of patient age on the risk of intracranial hemorrhage (ICH) in premature neonates treated with extracorporeal membrane oxygenation (ECMO).

STUDY DESIGN

This was a retrospective cohort study of neonates of <37 weeks' gestation treated with ECMO in the years 1992 through 2000 and reported to the Extracorporeal Life Support Organization Registry (n=1524). The relation between ICH and patient age, defined as gestational age, postnatal age (PNA), and postconceptional age (PCA), was determined with the use of multiple logistic regression analysis.

RESULTS

PNA was inversely correlated with ICH in the univariate analysis (P=.01) but not in the multivariate analysis (P=.36). PCA showed a strong univariate correlation with decreasing ICH: 26% of patients </=32 weeks' PCA developed ICH as compared with 6% of patients with PCA of 38 weeks (P=.004). Multiple logistic regression identified as independent predictors of ICH: PCA (P=.005), sepsis (P=.004), acidosis (P=.0004), and treatment with sodium bicarbonate (P=.002). Gestational age was correlated with ICH in the multivariate model only when PNA was included.

CONCLUSIONS

Postnatal age is not a strong independent predictor of ICH in premature neonates treated with ECMO. PCA is the best age-related predictor of ECMO-related ICH in premature infants.

Expanded application of extracorporeal membrane oxygenation in a pediatric surgery practice

OBJECTIVE

To examine the breadth of application and resulting outcomes in a university-based extracorporeal membrane oxygenation (ECMO) program directed by pediatric surgeons.

SUMMARY BACKGROUND DATA

Several randomized control trials have supported the use of ECMO in neonates with respiratory failure. No comparable data exist for older children and young adults who may be afflicted with a variety of uncommon conditions. The indications for ECMO in these patients remain controversial.

METHODS

Patient data were recorded prospectively and reported to the Extracorporeal Life Support Organization. These data were analyzed by indications and outcomes on all patients treated since the inception of the program.

RESULTS

Two hundred sixteen patients were treated with 225 courses of ECMO. Neonates (188 [87%]) outnumbered 28 older patients (aged 6 weeks to 22 years). Overall, 174 patients survived (81%). Sixty-four of 65 (98.5%) neonates with meconium aspiration syndrome survived. ECMO support after heart (3), lung (2), heart-lung (1), and liver (1) transplant yielded a 57% survival to discharge. ECMO also resulted in survival of patients with uncommon conditions, including severe asthma (1), hydrocarbon aspiration (1/2), congestive heart failure due to a cerebral arteriovenous malformation (1), tracheal occlusion incurred during endoscopic stent manipulation (2), meningitis (1), and viral pneumonia (3/5).

CONCLUSIONS

ECMO can potentially eliminate mortality for meconium aspiration syndrome. Survival for other causes of respiratory failure in neonates and older children, while not as dramatic, still surpasses that anticipated with conventional therapy. Moreover, survival of transplant patients has been comparable to that achieved in other children.

A review of 100 patients transported on extracorporeal life support

Between May 1990 and January 1999, 100 patients (68 adult, 32 pediatric) with severe respiratory or cardiac instability were successfully transported to the University of Michigan Medical Center on extracorporeal life support. Diagnoses included adult respiratory distress syndrome (n = 78), cardiac failure (n = 7), sepsis (n = 7), asthma (n = 5), respiratory distress syndrome (of newborn) (n = 2), and airway compromise (n = 1). Of the patients, 53 were supported with venovenous bypass and 47 with venoarterial bypass. Patients were transported by ground ambulance (n = 80), helicopter (n = 15), or fixed-wing aircraft (n = 5). The median transport distance was 44 miles (range 2-790 miles), and the median transport time was 5 hours and 30 minutes (range: 1 h 33 min to 16 h 6 min). Sixty-six patients (66%) survived to discharge. One death occurred during cannulation, and two patients died before cannulation began. Complications that occurred during transport included 10 cases of electrical failure, 3 cases of circuit tubing leakage, and 1 case each of circuit rupture, membrane lung thrombosis, and membrane lung leakage. None of the complications occurring during transport had an adverse effect on outcome. We conclude that the long distance transport of patients on extracorporeal life support can be safely accomplished and is an effective option for the unstable patient with severe respiratory or cardiac failure.

The impact of changing neonatal respiratory management on extracorporeal membrane oxygenation utilization

BACKGROUND

The introduction of inhaled nitric oxide (INO) and high-frequency oscillatory ventilation (HFV) has had a profound effect on the use of extracorporeal membrane oxygenation (ECMO) for respiratory failure in neonates without congenital diaphragmatic hernia (CDH). The purpose of this study was to evaluate the changes in the demographics and outcome of non-CDH neonates who underwent ECMO for hypoxemic respiratory failure.

METHODS

All neonates (non-CDH and noncardiac) who underwent ECMO between January 1, 1989 and January 1, 2001 were reviewed. Patients were separated into 3, 4-year periods for comparison (period A, 1989 through 1992; B, 1993 through 1996; C, 1997 through 2000). Data were examined by analysis of variance and contingency table analysis.

RESULTS

There was a progressive decline in the total number of neonates requiring ECMO over time (period A, 172; B, 114; C, 56; P <.01). The utilization of pre-ECMO alternate respiratory therapies such as INO (period A, 0%; B, 23%; C, 98%; P <.01) and HFV (period A, 9%; B, 61%; C, 89%; P <.01) have increased significantly associated with an increase in the age of ECMO initiation (Period A, 40.5 hours; B, 58.3 hours; C, 68.5 hours; P <.01). The length of ECMO run also has increased (period A, 154.7 hours; B, 193.0 hours; C, 174.5 hours; P <.01), but the overall mortality rate has remained unchanged.

CONCLUSIONS

With the increasing use of INO and HFO, the absolute number of non-CDH, noncardiac neonates with hypoxemic respiratory failure requiring ECMO has decreased. Initiation of ECMO has become progressively later likely because of the use of these rescue therapies, but the overall mortality rate remains unchanged despite this delay.

A 16-year neonatal/pediatric extracorporeal membrane oxygenation transport experience

OBJECTIVE

To characterize the population and survival of neonatal and pediatric patients transported by Wilford Hall Medical Center (WHMC) on extracorporeal membrane oxygenation (ECMO) since 1985.

STUDY DESIGN

A retrospective chart, literature, and database review of pediatric and neonatal patients transported on ECMO by the WHMC ECMO transport team. In addition, a subpopulation analysis was performed comparing neonates with meconium aspiration syndrome (MAS) placed on ECMO at WHMC with those infants with MAS transported on ECMO. Characteristics of interest for this comparison included disease severity before ECMO, age at initiation of ECMO, survival, ECMO-related complications, and duration of ECMO support.

RESULTS

Forty-two patients transported on ECMO were identified: 23 neonatal respiratory cases (survival 57%), 7 pediatric respiratory cases (survival 71%), 4 cardiac cases (survival 50%), and 8 extra-institutional ECMO transports (survival 63%). In the MAS subpopulation, there was significantly greater survival in the in-house group--97% (31/32)--than in the ECMO transport group--75% (9/12); there were no other significant differences between these groups. Overall, no ECMO-related complications leading to patient demise could be identified in the ECMO transport group.

CONCLUSIONS

ECMO transport, although demonstrating acceptable survival, is a risk-laden modality that should not replace early referral to an ECMO center.

Delayed institution of extracorporeal membrane oxygenation is associated with increased mortality rate and prolonged hospital stay

BACKGROUND/PURPOSE

Severe meconium aspiration syndrome (MAS) is a frequent indication for extracorporeal membrane oxygenation (ECMO). Trials of less invasive cardiopulmonary support may result in fewer infants treated with ECMO but could delay institution of ECMO. The authors hypothesized that those infants with severe MAS who are treated with ECMO early will have a lower mortality rate and a shorter hospital course than those who receive delayed ECMO.

METHODS

A retrospective review of all patients with MAS in the national extracorporeal life support (ELSO) registry for the decade 1989 through 1998 was performed. Data from the ELSO registry were examined for demographics, clinical parameters, and treatment course. Patients were divided into 3 groups based on the time from birth to institution of ECMO: group 1, 0 to 23 hours; group 2, 24 to 96 hours; and group 3, greater than 96 hours. These groups were compared for survival, duration of extracorporeal support, and duration of ventilatory support after ECMO. Statistical relevance was determined by analysis of variance (ANOVA) and Tukey's post-hoc test.

RESULTS

A total of 3,235 of 4,002 patients with MAS had complete information on duration of mechanical ventilation. Overall mortality rate was 5.8%. The mortality rate in group 1 (n = 1,266) was 4.8%, group 2 (n = 1,568) 6.0%, and group 3 (n = 401) 7.7%. An increased time to ECMO was associated with a significant increase in mortality rate (P <.05). This also was associated with significant increases in the length of the ECMO run (157 +/- 4 v 130 +/- 2 hours, P =.02) and duration of post-ECMO ventilation (157 +/- 17 v 118 +/- 3 hours; P <.001). Those patients in groups 1 and 2 who did not respond to a trial of high-frequency oscillatory ventilation had significantly longer ECMO runs (129 +/- 2 v 113 +/- 1 hours; P =.001) and longer post-ECMO ventilator courses (137 +/- 2 v 114 +/- 1 hours; P =.002) than those who did not.

CONCLUSIONS

Delay in institution of ECMO for MAS results in prolonged ECMO and need for post-ECMO ventilation. Consideration should be given to instituting ECMO earlier in patients with severe MAS.

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

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

Epidemiology of neonatal respiratory failure in the United States: projections from California and New York

We wanted to determine the incidence, cost, outcome, and patterns of care for neonates requiring mechanical ventilation (MV) in the United States. Using 1994 state hospital discharge data from California and New York, we conducted an observational study of all neonatal hospitalizations (n = 16,405) with MV, comparing outcomes at centers of different technological capability, and generating national projections using census and natality reports. The MV rate was 18 per 1,000 live births. Although the incidence was much higher in lower birth weight (BW) babies, one-third had normal BW. The incidence was higher in boys (20 versus 15.6 per 1,000) and in blacks (29 per 1,000). Hospital mortality was 11.1%, higher in minority groups, and associated with low BW, congenital anomalies, and major hemorrhage. Mean hospital length of stay and costs were 31.1 d and $51,700. Half of all deaths occurred at lower level centers. There are 80,000 cases per year in the United States with 8,500 deaths and total hospital costs of $4.4 billion. We conclude neonatal respiratory failure is common, expensive, and frequently fatal. There are a surprisingly large number of normal BW cases and there are large racial differences.

Extracorporeal membrane oxygenation 2001. The odyssey continues

Extracorporeal membrane oxygenation was established as a standard of care by demonstrating its ability to save lives in moribund infants. The designs of early studies provided no living cohorts of similarly ill patients by which to measure accurately other (and perhaps to many more important) outcomes of interest: long-term neurodevelopmental outcomes or cost. Prospective cohort studies of neurodevelopmental outcomes post-ECMO demonstrate: (1) because ECMO, as used, saves lives, there will be an increase in the absolute number of handicapped children surviving; (2) there is little evidence that ECMO creates a relative increase in the percent of handicapped children surviving severe respiratory failure. The high direct costs of an ECMO program are measured and well publicized. When such costs are compared with similar therapies in other fields (in such terms as cost per survivor), the cost of ECMO does not seem to be an outlier. Trials of newer therapies, such as iNO, show the capacity to decrease the use of ECMO but have failed to demonstrate either cost-effectiveness or better long-term outcomes. It has not been shown that either society or individual patients have benefited from the decreased need for ECMO.

Lung salvage and protection ventilatory techniques

Physicians are in the beginning of an era in intensive care medicine in which they finally are starting to see improved outcomes in patients with AHRF. At the same time, intensivists are presented with a bewildering choice of ventilator options and adjunctive therapies. Trying to sort out which are "cosmetic," that is, improve the blood gases as opposed to influencing the outcome, remains a challenge and will be resolved only with additional RCTs. Principles of ventilator management that are driven by mimicking normal physiology are inappropriate and must be rethought.

Mechanical Cardiopulmonary Support of Infants and Children With Congenital Heart Disease

Cardiac indications for the use of mechanical cardiopulmo nary support techniques in infants and children include short-term circulatory support during reversible myocardial failure, cardiopulmonary support before and after cardiac surgery, and a bridge to cardiac transplantation. For practi cal purposes, 3 modalities are currently available for these patients: extracorporeal membrane oxygenation, use of ven tricular assist devices, and intra-aortic balloon pump coun terpulsation. Although a variety of devices are available for larger patients, the need for smaller sizes and a wider range of sizes has delayed their use in children. This article sum marizes the current systems available for children as well as indications and outcome data related to their use in infants and children with congenital or acquired heart disease. Copyright © 2001 by W.B. Saunders Company.

The changing demographics of neonatal extracorporeal membrane oxygenation patients reported to the Extracorporeal Life Support Organization (ELSO) Registry

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is an important treatment tool in the management of near-term and term neonates with severe hypoxemic respiratory failure. To better understand how health care for patients treated with ECMO has changed, we studied the demographic and treatment data reported to the Extracorporeal Life Support Organization (ELSO) registry from January 1, 1988, through January 1, 1998.

METHODS

We used data stored in the ELSO registry and evaluated the changes in demographics, use of alternate therapies before ECMO, severity of illness, duration of ECMO therapy, and mortality over a 10-year period. All data on neonates reported between January 1, 1988, and January 1, 1998 were used. Verification checks were performed on all fields to eliminate nonsense outliers. We separated the neonates into 2 groups-those with and those without a congenital diaphragmatic hernia (CDH). All analyses were performed on the total group and each subgroup separately. Changes in continuous data were analyzed by year using analysis of variance. Year differences in categorical data were evaluated with chi(2) analysis. We also used the linear trend test and the Cochran-Armitage trend test to evaluate time-related changes.

RESULTS

We reviewed 12 175 neonates. Over the decade, there were no changes in mean gestational age, gender, age at which ECMO was started, pH, or PaCO(2) just before ECMO. The proportion of neonates with CDH increased from 18% to 26%, while the proportion with respiratory distress syndrome decreased from 15% to 4%. Other diagnostic categories remained constant. The use of surfactant, high-frequency ventilation, and inhaled nitric oxide increased from 0% in 1988 to 36%, 46%, and 24%, respectively, in 1997. The mean peak pressure being used just before ECMO decreased (47 +/- 10 in 1988 to 39 +/- 12 in 1997), and the mean PaO(2)/FIO(2) ratio increased (38 +/- 23 in 1988 to 48 +/- 36 in 1997). The primary mode of ECMO remains venoarterial; however, the use of venovenous ECMO increased from 1% to 32% over the decade. Duration of ECMO treatment increased overall, and this trend was seen for patients with and without CDH (124 +/- 67 to 141 +/- 104 hours for the non-CDH group, 161 +/- 99 to 238 +/- 141 hours for the CDH group). The number of centers reporting neonatal data to the ELSO registry increased from 52 in 1988 to a peak of 100 in 1993. In 1997, 96 centers reported data to ELSO. The average number of neonatal patients reported from each site decreased from a peak of 18 in 1991 to 9 in 1997. Mortality increased from 18% to 22%; however, when corrected for the relative increase in neonates with CDH, this trend disappeared. Diagnoses-specific mortality rates remained constant. The occurrence of intracranial hemorrhage and/or infarct also stayed constant at 16%.

CONCLUSIONS

The population of neonates treated with ECMO in 1997 was very different from patients treated in the 1980s and early 1990s. They were exposed to an ever-expanding group of new therapies, appeared to be healthier based on indices of gas exchange, and were cared for at centers that reported fewer cases per year.

Decreased use of neonatal extracorporeal membrane oxygenation (ECMO): how new treatment modalities have affected ECMO utilization

OBJECTIVE

Over the last decade, several new therapies, including high-frequency oscillatory ventilation (HFOV), exogenous surfactant therapy, and inhaled nitric oxide (iNO), have become available for the treatment of neonatal hypoxemic respiratory failure. The purpose of this retrospective study was to ascertain to what extent these modalities have impacted the use of neonatal extracorporeal membrane oxygenation (ECMO) at our institution.

METHODS

Patients from 2 time periods were evaluated: May 1, 1993 to November 1, 1994 (group 1) and May 1, 1996 to November 1, 1997 (group 2). During the first time period (group 1), HFOV was not consistently used; beractant (Survanta) use for meconium aspiration syndrome (MAS), persistent pulmonary hypertension of the newborn (PPHN), and pneumonia was under investigation; and iNO was not yet available. During the second time period (group 2), HFOV and beractant treatment were considered to be standard therapies, and iNO was available to patients with oxygenation index (OI) >/=25 x 2 at least 30 minutes apart, or on compassionate use basis. Patients were included in the data collection if they met the following entry criteria: 1) OI >15 x 1 within the first 72 hours of admission; 2) EGA >/=35 weeks; 3) diagnosis of MAS, PPHN or sepsis/pneumonia; 4) <5 days of age on admission; and 5) no congenital heart disease, diaphragmatic hernia, or lethal congenital anomaly.

RESULTS

Of the 49 patient in group 1, 21 (42.8%) required ECMO therapy. Of these ECMO patients, 14 (66.6%) had received diagnoses of MAS or PPHN. Only 3 of the patients that went on to ECMO received beractant before the initiation of bypass (14.3%). All ECMO patients in group 1 would have met criteria for iNO had it been available. Of all patients in group 1, 18 (36.7%) were treated with HFOV, and 13 (26.5%) received beractant. Of the 47 patients in group 2, only 13 (27.7%) required ECMO therapy (compared with group 1). Of these ECMO patients, only 5 (38.5%) had diagnoses of MAS or PPHN, with the majority of patients (61.5%) requiring ECMO for sepsis/pneumonia, with significant cardiovascular compromise. Only 5 of these ECMO patients, all outborn, did not receive iNO before cannulation because of the severity of their clinical status on admission. Of all patients in group 2, 41 (87.2%) were treated with HFOV (compared with group 1), 42 (89.3%) received beractant (compared with group 1), and 18 (44.7%) received iNO.

CONCLUSIONS

The results indicate that ECMO was used less frequently when HFOV, beractant and iNO was more commonly used. The differences in treatment modalities used and subsequent use of ECMO were statistically significant. We speculate that, in this patient population, the diagnostic composition of neonatal ECMO patients has changed over time.

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.

Improved oxygenation in a randomized trial of inhaled nitric oxide for persistent pulmonary hypertension of the newborn

OBJECTIVE

To determine the effect of inhaled nitric oxide (NO) on clinical outcome in newborns with persistent pulmonary hypertension (PPHN).

DESIGN

A prospective, randomized trial of patients referred to a level 3 nursery in a single large center. Clinicians were not masked to group assignment. Crossover of patients from control to NO treatment was not permitted.

METHODS

We randomized 49 mechanically ventilated newborns, transferred to our center with clinical and echocardiographic evidence of severe PPHN (arterial oxygen tension [PaO2] <100; fractional inspired oxygen = 1) to treatment with or without NO. Patients with gestational age <34 weeks or with congenital heart disease or diaphragmatic hernia were excluded. High-frequency oscillatory ventilation was used but not allowed concomitantly with NO. Primary outcome variables were oxygenation, mortality, and use of extracorporeal membrane oxygenation (ECMO).

RESULTS

Meconium aspiration syndrome and isolated PPHN were the most common diagnoses (32/49) and were distributed equally between groups. The median age at the time of entry into the study was similar between groups, 25 hours for control patients and 18 hours for NO patients. Median baseline oxygenation index (OI) was similar in 23 control (OI = 29) and 26 NO (OI = 30) patients. Mortality (8%), use of ECMO (33%), median days on mechanical ventilation (9 days), and duration of supplemental oxygen (13 days) were not different between treatment groups. PaO2, oxygen saturation, and OI improved in the NO group compared with baseline and to control patients at 15 minutes. The median percent change in OI (-31%) in the NO group was significantly different from baseline and from the control group. The difference in oxygenation between treatment groups was still apparent 12 hours after baseline. Before cannulation for ECMO, oxygenation was better in the NO group compared with control patients. Among patients who were placed on ECMO, the median time from baseline to ECMO cannulation was 2.4 hours (range, 1 to 12 hours) among control patients and 3.3 hours (range, 2 to 68 hours) for those randomized to receive NO. There was a tendency to observe fewer adverse neurologic events (seizure and intracranial hemorrhage) in the NO group (4/26 vs 8/23). One child with alveolar capillary dysplasia confirmed by postmortem examination could not be weaned from 80 parts per million of NO and transiently developed methemoglobinemia (peak methemoglobin level = 17%). No other side effects were observed.

CONCLUSIONS

Although mortality and ECMO use were similar for both treatment groups using this study size and design, sustained improvement in oxygenation with NO and better oxygenation at initiation of ECMO may have important clinical benefits. We speculate that modification of treatment to include specific lung expansion strategies with NO treatment and recognition that early improvement of oxygenation may be sustained with NO may lead to reduced use of ECMO in NO treated patients compared with controls.