Extracorporeal Membrane Oxygenation and Conventional Medical Therapy in Neonates With Persistent Pulmonary Hypertension of the Newborn: A Prospective Randomized Study

Impact of Kidney Disease on Survival in Neonatal Extracorporeal Life Support

OBJECTIVE

To investigate the prevalence and survival to discharge of neonates with kidney disease who received extracorporeal life support.

DESIGN

We analyzed the Extracorporeal Life Support Organization international registry of neonates (< 30 d old) who received extracorporeal life support from 1989 to 2012. We used International Classification of Diseases and Related Health Problems, 9th Revision, Clinical Modification, codes to identify neonates with kidney disease at time of cannulation for extracorporeal life support.

SETTING

Participating Extracorporeal Life Support Organization centers.

PATIENTS

All neonates who received extracorporeal life support at an Extracorporeal Life Support Organization center from 1989 to 2012.

INTERVENTIONS

We performed bivariate logistic regression to estimate associations between survival and covariates. We used unadjusted and adjusted logistic regression to compare survival to discharge between neonates with and without kidney disease. Odds ratios were estimated separately for three groups based on extracorporeal life support indication: pulmonary indication without congenital diaphragmatic hernia, pulmonary indication with congenital diaphragmatic hernia, and cardiac indication. Adjusted models included covariates identified as significant in bivariate models for each group.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure was survival to discharge from hospitalization. Of the 28,755 neonates who received extracorporeal life support, 405 had kidney disease (extracorporeal life support indication: 210 pulmonary indication without congenital diaphragmatic hernia, 65 pulmonary indication with congenital diaphragmatic hernia, and 130 cardiac indication). Survival was lower in neonates with kidney disease than those without (49% vs 82% pulmonary indication without congenital diaphragmatic hernia, 25% vs 51% pulmonary indication with congenital diaphragmatic hernia, 21% vs 41% cardiac indication). Kidney disease was associated with reduced survival in adjusted models (95% CI for odds ratio 0.31-0.59 pulmonary indication without congenital diaphragmatic hernia, 0.27-0.89 pulmonary indication with congenital diaphragmatic hernia, 0.31-0.77 cardiac indication).

CONCLUSIONS

Neonates with kidney disease who receive extracorporeal life support have poorer survival to discharge compared with other neonates who receive extracorporeal life support, suggesting that kidney disease should be considered when making extracorporeal life support initiation decisions.

Percutaneous cannulation for extracorporeal membrane oxygenation by intensivists: a retrospective single-institution case series

OBJECTIVE

Extracorporeal membrane oxygenation provides support for patients with severe acute cardiopulmonary failure, allowing the application of lung or myocardial rest in anticipation of organ recovery, or as a bridge to long-term support. Advances in technology have improved the safety and ease of application of extracorporeal membrane oxygenation. Percutaneous cannulation is one of these advances and is now preferred over surgical cannulation in most cases. Percutaneous cannulation is increasingly performed by intensivists, cardiologists, interventional radiologists, and related specialties. The objective of this study is to review the experience of percutaneous cannulation by intensivists at a single institution.

DESIGN

A retrospective review of 100 subjects undergoing percutaneous cannulation for extracorporeal membrane oxygenation.

SETTING

Adult ICUs and PICUs at a tertiary academic medical institution.

PATIENTS

Critically ill neonatal, pediatric, and adult subjects with severe respiratory and/or cardiac failure undergoing percutaneous cannulation for extracorporeal membrane oxygenation. Modes of support included venoarterial, venovenous, venovenoarterial, and arteriovenous.

INTERVENTIONS

Percutaneous extracorporeal membrane oxygenation.

MEASUREMENTS AND MAIN RESULTS

Case reports submitted to the Extracorporeal Life Support Organization and hospital records of the subjects were retrospectively reviewed. Subject demographics, type of support, cannulation configuration, types of cannulas, use of imaging modalities, and complications were recorded and summarized. One hundred ninety cannulations with cannula sizes from size 12 to 31F were performed by four intensivists in 100 subjects. Twenty-three were arterial (12-16F) and 167 were venous (12-31F). Preinsertion ultrasound was performed in 93 subjects (93%), fluoroscopic guidance in 79 subjects (85% of nonarteriovenous subjects), and ultrasound-guided insertion was performed in 65 subjects (65%). Two major complications occurred, each associated with mortality. Cannulation was successful in all other subjects (98% of subjects and 99% of cannulations). There were no cases of cannula-related bloodstream infection.

CONCLUSIONS

Percutaneous cannulation for extracorporeal membrane oxygenation by intensivists can be performed with a high rate of success and a low rate of complications when accompanied by imaging support.

Extracorporeal support in children with pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

Extracorporeal life support has undergone a revolution in the past several years with the advent of new, miniaturized equipment and success in supporting patients with a variety of illnesses. Most experience has come with the use of extracorporeal membrane oxygenation, a modified form of cardiopulmonary bypass that can support the heart, lungs, and circulation for days to months at a time. To describe the recommendations for the use of extracorporeal membrane oxygenation in children with pediatric acute respiratory distress syndrome based on a review of the literature and expert opinion.

DESIGN

Consensus conference of experts in pediatric acute lung injury.

METHODS

A panel of 27 experts met over the course of 2 years to develop a taxonomy to define pediatric acute respiratory distress syndrome and to make recommendations regarding treatment and research priorities. The extracorporeal support subgroup comprised two international experts. When published data were lacking, a modified Delphi approach emphasizing strong professional agreement was used.

RESULTS

The Pediatric Acute Lung Injury Consensus Conference experts developed and voted on a total of 151 recommendations addressing the topics related to pediatric acute respiratory distress syndrome, 11 of which related to extracorporeal support. All recommendations had agreement, with 10 recommendations (91%) achieving strong agreement. These recommendations included the utilization of extracorporeal support for reversible causes of pediatric acute respiratory distress syndrome, consideration of quality of life when making the decision to use extracorporeal support, and the use of the Extracorporeal Life Support Organization registry to report all extracorporeal support activity, among others.

CONCLUSIONS

Pediatric extracorporeal membrane oxygenation for pediatric acute respiratory distress syndrome could benefit from more specific data collection and collaboration of focused investigators to establish validated criteria for optimal application of extracorporeal membrane oxygenation and patient management protocols. Until that time, consensus opinion offers some insight into guidelines.

Stroke in children with cardiac disease: report from the International Pediatric Stroke Study Group Symposium

BACKGROUND

Cardiac disease is a leading cause of stroke in children, yet limited data support the current stroke prevention and treatment recommendations. A multidisciplinary panel of clinicians was convened in February 2014 by the International Pediatric Stroke Study group to identify knowledge gaps and prioritize clinical research efforts for children with cardiac disease and stroke.

RESULTS

Significant knowledge gaps exist, including a lack of data on stroke incidence, predictors, primary and secondary stroke prevention, hyperacute treatment, and outcome in children with cardiac disease. Commonly used diagnostic techniques including brain computed tomography and ultrasound have low rates of stroke detection, and diagnosis is frequently delayed. The challenges of research studies in this population include epidemiologic barriers to research such as small patient numbers, heterogeneity of cardiac disease, and coexistence of multiple risk factors. Based on stroke burden and study feasibility, studies involving mechanical circulatory support, single ventricle patients, early stroke detection strategies, and understanding secondary stroke risk factors and prevention are the highest research priorities over the next 5-10 years. The development of large-scale multicenter and multispecialty collaborative research is a critical next step. The designation of centers of expertise will assist in clinical care and research.

CONCLUSIONS

There is an urgent need for additional research to improve the quality of evidence in guideline recommendations for cardiogenic stroke in children. Although significant barriers to clinical research exist, multicenter and multispecialty collaboration is an important step toward advancing clinical care and research for children with cardiac disease and stroke.

Extracorporeal membrane oxygenation-hemostatic complications

The use of extracorporeal membrane oxygenation (ECMO) support for cardiac and respiratory failure has increased in recent years. Improvements in ECMO oxygenator and pump technologies have aided this increase in utilization. Additionally, reports of successful outcomes in supporting patients with respiratory failure during the 2009 H1N1 pandemic and reports of ECMO during cardiopulmonary resuscitation have led to increased uptake of ECMO. Patients requiring ECMO are a heterogenous group of critically ill patients with cardiac and respiratory failure. Bleeding and thrombotic complications remain a leading cause of morbidity and mortality in patients on ECMO. In this review, we describe the mechanisms and management of hemostatic, thrombotic and hemolytic complications during ECMO support.

A paradigm shift in the treatment of extreme prematurity: the artificial placenta

PURPOSE OF REVIEW

Extremely low gestational age newborns (ELGANs), born at less than 28 weeks' estimated gestational age, suffer the greatest consequences of prematurity. There have been significant advances in their care over the last several decades, but the prospects for major advances within traditional treatment modalities appear limited. An artificial placenta using extracorporeal life support (ECLS) has been investigated in the laboratory as a new advance in the treatment of ELGANs. We review the concept of an artificial placenta, the purported benefits, and the most recent research efforts in this area.

RECENT FINDINGS

For 50 years, researchers have attempted to develop an artificial placenta based on ECLS. Traditional artificial placenta strategies have been based on arteriovenous ECLS using the umbilical vessels with moderate success. Recently, the use of venovenous ECLS and miniaturization of ECLS components have shown potential for creating a next-generation artificial placenta.

SUMMARY

ELGANs suffer the greatest morbidity and mortality of prematurity, and are poised to benefit from a paradigm shift in the treatment. Although challenges remain, the artificial placenta is feasible. An artificial placenta would not only protect ELGANs from the complications of mechanical ventilation, but also support their development until a stage of greater maturity, preparing them for a life free of the sequelae of prematurity.

[Current state of neonatal extracorporeal membrane oxygenation in Colombia: description of the first cases]

Extracorporeal membrane oxygenation is considered a rescue therapy and complex vital support with benefits in cardiorespiratory diseases during neonatal period that fulfil the characteristics of being reversible in neonates older than 34 weeks. The criteria for patient selection and its prompt use are critical for the final result. Even though new alternatives for management of hypoxemic respiratory failure in full term and almost full term neonates have decreased its use, congenital diaphragmatic hernia continues being a complex disease where it can have some applicability. Even though our experience is beginning, constant training will make of extracorporeal membrane oxygenation an option for complex patients in whom maximum therapy fails. This is a report of the first neonatal cases of hypoxemic respiratory failure managed at Fundación Cardiovascular de Colombia.

Is age at initiation of extracorporeal life support associated with mortality and intraventricular hemorrhage in neonates with respiratory failure?

OBJECTIVE

To describe differences in characteristics among neonates treated with extracorporeal life support (ECLS) in the first week of life for respiratory failure compared with later in the neonatal period and to assess risk factors for central nervous system (CNS) hemorrhage and mortality among the two groups.

STUDY DESIGN

Review of the Extracorporeal Life Support Organization registry from 2001 to 2010 of neonates ⩽30 days comparing two age groups: those ⩽7 days (Group 1) to those >7 days (Group 2) at ECLS initiation.

RESULT

Among 4888 neonates, Group 1 (n=4453) had significantly lower mortality (17 vs 39%, P<0.001) but greater CNS hemorrhage (11 vs 7%, P=0.02) than Group 2 (n=453). Mortality and CNS hemorrhage improved significantly with increasing gestational age only for Group 1 patients. CNS hemorrhage occurred more frequently in Group 1 patients receiving venoarterial (VA) than with venovenous ECLS (15 vs 7%, P<0.001). In Group 1, lower birth weight and pre-ECLS pH and VA mode were independently associated with mortality. In Group 2, higher mean airway pressure was independently associated with mortality. Complications of ECLS therapy, including CNS hemorrhage and renal replacement therapy were independently associated with mortality for both groups.

CONCLUSION

Neonates cannulated for ECLS after the first week of life had greater mortality despite lower CNS hemorrhage than neonates receiving ECLS earlier. Premature infants cannulated after 1 week had fewer CNS hemorrhages than premature infants treated with extracorporeal membrane oxygenation starting within the first week of life.

Neonatal extracorporeal membrane oxygenation: Initial experience of Hospital de São João

The purpose of this series is to report the initial ECMO experience of the Neonatal Intensive Care Unit of Hospital de São João. The first three clinical cases are reported. Case report 1: a 39 weeks gestational age girl with severe lung hypoplasia secondary to a bilateral congenital diaphragmatic hernia. Case report 2: a 39 weeks gestational age girl with a right congenital diaphragmatic hernia and a tracheal stenosis. Case report 3: a 34 weeks gestational age boy, with 61 days of life, with a Bordetella pertussis pneumonia, severe pulmonary hypertension, shock, hyperleukocytosis and seizures.

Evaluation of the oxygenation index in adult respiratory failure

BACKGROUND

The oxygenation index (mean airway pressure × FIO2 divided by PaO2) was originally devised to measure severity of illness and predict outcome in neonatal respiratory failure. We evaluated the discrimination of a modified oxygenation index (modified with age) for predicting 28-day mortality in adults with respiratory failure (adult respiratory distress syndrome [ARDS]) using the ALVEOLI section of the ARDSNet database and validated the results in the full ARDSNet database.

METHODS

We compared age-adjusted oxygenation index (AOI) on ventilator Days 1 to 4 with 28-day mortality.

RESULTS

AOI correlated positively with mortality (area under the receiver operating characteristic curve, 0.70-0.74, for ARDS Days 1-4). Following initial development, AOI related to mortality was validated in two other ARDSNet databases producing similar results (area under the receiver operating characteristic curve, 0.70-0.78).

CONCLUSION

The observed sensitivity and specificity analysis demonstrated that AOI is equivalent to or better than other mortality prediction systems used for ARDS.

LEVEL OF EVIDENCE

Prognostic, level III.

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.

ECLS for preemies: the artificial placenta

The high mortality and morbidity associated with respiratory failure among extremely low gestational age newborns (ELGANs) remains an unsolved problem. A logical strategy to avoid these complications would involve re-creating the intrauterine environment with extracorporeal membrane oxygenation (ECMO) instead of mechanical ventilation. Such a device, termed an artificial placenta, was first researched over 50 years ago. AP models vary, but all incorporate ECMO involving the umbilical vessels, lack of mechanical ventilation, and low partial pressure of oxygen to preserve fetal circulation. Current research has focused on low-volume pumpless arteriovenous circuits as well as pump-driven venovenous circuits.

Clinical research in pediatric organ transplantation

Solid organ transplantation has greatly improved survival in children with end-stage disease, becoming one of the main treatment options in this population. Nonetheless, there are significant challenges associated with validating and optimizing the effects of these interventions in clinical trials. Therefore, we reviewed the main issues related to conducting clinical transplantation research in children. We divided these challenges into three different categories: (i) challenges related to surgical techniques and anesthetic procedures, (ii) challenges related to post-transplant care and (iii) challenges specific to a particular population group and disease type. Some of the observed burdens for clinical research in this field are related to the limitations of conducting studies with a placebo or sham procedure, determining the standard of care for a control group, low prevalence of cases, ethical concerns related to use of a placebo control group and lack of generalizability from animal studies and clinical trials conducted in adult populations. To overcome some of these barriers, it is necessary to utilize alternative clinical trial designs, such as observational studies or non-inferiority trials, and to develop multicenter collaborations to increase the recruitment rate. In conclusion, the lack of robust data related to pediatric transplantation remains problematic, and further clinical trials are needed to develop more efficacious and safer treatments.

Survival of newborn infants with severe respiratory failure before and after establishing an extracorporeal membrane oxygenation program

BACKGROUND

Severe hypoxic respiratory failure is a leading cause of neonatal mortality in Chile. Extracorporeal membrane oxygenation improves survival in neonates with hypoxic respiratory failure.

OBJECTIVE

To determine the impact of the establishment of a Neonatal Extracorporeal Membrane Oxygenation Program on the outcome of newborns with severe hypoxic respiratory failure in a developing country.

DESIGN/PATIENTS

Data of newborns (birthweight > 2,000 g and gestational age ≥ 35 wk) with hypoxic respiratory failure and oxygenation index greater than 25 were compared before and after extracorporeal membrane oxygenation was available. Extracorporeal membrane oxygenation was initiated in infants with refractory hypoxic respiratory failure who failed to respond to inhaled nitric oxide/high-frequency oscillatory ventilation.

MAIN RESULTS

Data from 259 infants were analyzed; 100 born in the pre-extracorporeal membrane oxygenation period and 159 born after the extracorporeal membrane oxygenation program was established. Patients were similar in terms of risk factors for death for both periods except for a higher oxygenation index and a greater proportion of outborn infants during the extracorporeal membrane oxygenation period. Survival significantly increased from 72% before extracorporeal membrane oxygenation to 89% during the extracorporeal membrane oxygenation period (p < 0.01). During the extracorporeal membrane oxygenation period, 98 of 159 patients (62%) with hypoxic respiratory failure were rescued using inhaled nitric oxide/high-frequency oscillatory ventilation, whereas 61 (38%) did not improve; 52 of these 61 neonates were placed on extracorporeal membrane oxygenation. Extracorporeal membrane oxygenation survival rate to discharge was 85%. After adjusting for potential confounders, the severity of the pretreatment oxygenation index, a late arrival to the referral center, the presence of a pneumothorax, and the diagnosis of a diaphragmatic hernia were significantly associated with the need for extracorporeal membrane oxygenation or death.

CONCLUSIONS

The establishment of an extracorporeal membrane oxygenation program was associated with a significant increase in the survival of newborns more than or equal to 35 weeks old with severe hypoxic respiratory failure.

[Interhospital transport with extracorporeal life support: results and perspectives after 5 years experience]

OBJECTIVE

Describing the experience of a referral center for interhospital patients transport treated with extracorporeal circulatory or respiratory support (ECLS), the difficulties encountered and the results obtained.

STUDY DESIGN

Retrospective and observational study.

PATIENTS AND METHODS

All patients with respiratory or circulatory failure accepted for extracorporeal assistance for which routine medical transport was life threatening.

STATISTICAL ANALYSIS

A descriptive analysis was performed (median and interquartile deviation). Comparison of biological data was performed using a non-parametric Wilcoxon test and 5 years overall survival was determined by a Kaplan-Meier analysis.

RESULTS

Over a 55-month period, 29 patients were selected for transportation under ECMO or ECLS. Indication was respiratory failure in 38 % of cases, hemodynamic instability in 52 % of cases and combined symptoms in 10 % of cases. Average duration of transportation was 40 km (9-64 km). No complication related to transport was observed. Incidence of intrahospital death was 57 %. There was no correlation between death and indication of ECLS. Five-year survival was 55 % and 39 % for venovenous and arteriovenous ECLS, respectively.

CONCLUSION

In our experience, interhospital transport of patients under ECMO is feasible in satisfactory conditions of safety with trained team and standard procedures.

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.

Advances in neonatal extracorporeal support: the role of extracorporeal membrane oxygenation and the artificial placenta

This review addresses the history and evolution of neonatal extracorporeal membrane oxygenation (ECMO), with a discussion of the indications, contraindications, modalities, outcomes, and impact of ECMO. Controversies surrounding novel uses of ECMO in neonates, namely ECMO for premature infants and ex utero intrapartum therapy with transition to ECMO, are discussed. The development of an extracorporeal artificial placenta for support of premature infants is presented, including the rationale, research, and challenges. ECMO has had a dramatic effect on the care of critically ill neonates over the past 4 decades, and there is great potential to expand these benefits in the future.

Improved survival in venovenous vs venoarterial extracorporeal membrane oxygenation for pediatric noncardiac sepsis patients: a study of the Extracorporeal Life Support Organization registry

BACKGROUND/PURPOSE

There are few studies comparing venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO) in pediatric noncardiac sepsis patients.

METHODS

Following approval, we reviewed the Extracorporeal Life Support Organization registry data from 1990 to 2008 for patients 0 to 18 years with a diagnosis of sepsis and without diagnosis of congenital heart disease. Survival to discharge was compared between VA and VV ECMO using χ(2) analysis and multivariable logistic regression.

RESULTS

Four thousand three hundred thirty-two ECMO runs were reviewed, 3256 VA (75%) and 1076 VV (25%). A majority of VA modality was noted in each decade studied. Overall survival was 68% and was higher in VV (79%) than in VA ECMO (64%, P < .001). Survival decreased with increasing age (73% in newborns ≤ 1 month, 40% in children 1 month to 12 years, and 32% in adolescents >12 years, P < .001). VA ECMO had increased mortality risk after adjustment for age, use of vasoactive agents, and advanced respiratory support (odds ratio, 2.06; 95% confidence interval, 1.74-2.44; P < .001).

CONCLUSIONS

These data demonstrate improved survival in VV vs. VA ECMO in select pediatric septic patients without congenital heart disease. When technically feasible, physicians should consider VV ECMO as first therapeutic choice in this patient population.

Advancing evidence in preterm neonatal medicine

Few interventions and treatments for premature infants have undergone the rigors of a randomized controlled trial (RCT), the cornerstone of evidence-based healthcare. Multiple barriers in establishing a quality evidence base for the care of preterm infants are examined including the systematic exclusion of children from drug trials, vulnerability of the infants, burden to families of the consent process for RCTs, and the lack of standard measurements and subgroup definitions that impede systematic reviews. Delays in getting evidence into practice are highlighted, including clinician knowledge of existing evidence, attitudes about the evidence, and behavior. Landmark trials are used as examples. Finally, a call for the research community to develop guidance on good clinical research practice for preterm infants is offered that will allow the synthesis of the totality of evidence.

The epidemiology of respiratory failure in neonates born at an estimated gestational age of 34 weeks or more

OBJECTIVE

To prospectively evaluate the primary causes for the use of mechanical ventilation in near-term neonates and to determine the rates of death, chronic lung disease, and neurological complications in these infants.

STUDY DESIGN

We collected data on 1011 neonates who were > or =34 weeks' estimated gestational age; intubated within 72 hours of birth; and expected to require ventilation for more than 6 hours.

RESULTS

The study population had a mean estimated gestational age of 37+/-2 weeks; had a mean birth weight of 2.9+/-0.6 kg; and were predominantly male (62%), white (69%), and delivered by cesarean section (55%). Respiratory distress syndrome (n=437) was the most common pulmonary illness. Chronic lung disease was diagnosed in 109 (11%); neurological complications were reported in 86 (9%); and 51 (5%) patients died.

CONCLUSIONS

Neonates > or =34 weeks who require mechanical ventilation represent a high-risk population who have significant morbidity and mortality.

A randomized trial of early versus standard inhaled nitric oxide therapy in term and near-term newborn infants with hypoxic respiratory failure

OBJECTIVE

Inhaled nitric oxide (iNO) reduces the use of extracorporeal membrane oxygenation (ECMO)/incidence of death in term and near-term neonates with severe hypoxic respiratory failure. We conducted a randomized, double masked, multicenter trial to determine whether administration of iNO earlier in respiratory failure results in additional reduction in the incidence of these outcomes.

METHODS

Neonates who were born at > or =34 weeks' gestation were enrolled when they required assisted ventilation and had an oxygenation index (OI) > or =15 and <25 on any 2 measurements in a 12-hour interval. Infants were randomized to early iNO or to simulated initiation of iNO (control). Infants who had an increase in OI to 25 or more were given iNO as standard therapy.

RESULTS

The trial enrollment was halted after 75% of target sample size was reached because of decreasing availability of eligible patients. The 150 infants who were given early iNO and 149 control infants had similar baseline characteristics. Arterial oxygen tension increased by >20 mm Hg in 73% of early iNO and 37% of control infants after study gas initiation. Control infants received standard iNO and deteriorated to OI >40 more often than infants who were given early iNO. The incidence of death (early iNO, 6.7% vs control, 9.4%), ECMO (10.7% vs 12.1%), and their combined incidence (16.7% vs 19.5%) were similar in both groups.

CONCLUSION

iNO improves oxygenation but does not reduce the incidence of ECMO/mortality when initiated at an OI of 15 to 25 compared with initiation at >25 in term and near-term neonates with respiratory failure.

Best evidence-based practices: a historic perspective

Neonatologists, neonatal nurses, and others who care for critically ill newborns hope that the care they provide will improve the health and the neurodevelopmental outcome of these neonates. In this progressive era of neonatal medicine, we must pause to look backward even as we look forward, taking full advantage of the opportunity to reflect on our short history and to review several important events in neonatal medicine that have contributed in a meaningful way to the evolution of evidence-based neonatal care. Six interventions highlight why randomized controlled trials are necessary to understand the risks and benefits of our interventions with premature and critically ill infants. We hope this history of the evolving practice of evidence-based neonatal care will enable the reader to have a greater appreciation for the consideration of each and every intervention that we take on behalf of the infants in our care.

Mechanical support of the pediatric cardiac patient

Increased understanding of the anatomical nuances of congenital heart defects, improved methods of myocardial preservation, and advances in surgical techniques have led to improved results and need for postoperative mechanical support in patients undergoing congenital heart surgery. However, there remains a small portion of patients with myocardial or pulmonary failure that can can be rescued by intelligent use of mechanical support. The most widely used form of mechanical support is extracorporeal membrane oxygenation (ECMO), which has been adapted for use in congenital heart patients as well as patients with respiratory failure. Recent reports have suggested that ventricular support devices may also be useful in this patient population. A promising new application of mechanical support is for rescue during cardiac arrest; surprisingly good results have been obtained in this obviously moribund group of patients. Future developments in mechanical support include more accurate identification of patients who will benefit from this therapy and technological advances that will provide greater biocompatibility and simplification of the support circuit. Copyright 2000 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.

Respiratory function in survivors of the United Kingdom Extracorporeal Membrane Oxygenation Trial

Extracorporeal membrane oxygenation (ECMO) improves survival in mature neonates with reversible lung disease. However, ECMO could result in survival of infants with severe respiratory dysfunction who would otherwise have died. Alternatively, infants receiving ECMO might be spared prolonged ventilation and consequent barotrauma, resulting in improved respiratory function. Our aim was to compare respiratory function at 1 yr of age in infants assigned to receive either ECMO or conventional management (CM). Seventy-eight surviving infants of the United Kingdom (UK) ECMO trial (51 in the ECMO group) were studied at 1 yr of age. Questionnaires provided details of respiratory symptoms, and laboratory measurements of respiratory function were made for respiratory rate, tidal volume, lung volume, airway conductance, specific airway conductance, and maximal expiratory flow at FRC (Vmax (FRC)). Data were exchanged on floppy disk for cross-analysis and to ensure that investigators were blinded to the status of the infants. There was a wide spectrum of respiratory function, from normal to markedly abnormal. There were few differences between the groups, but in the CM group lung volume was increased (95% confidence intervals [CIs] of the difference in ECMO versus CM subjects: -67; -4 ml), and inspiratory specific conductance was lower (95% CI: 0.03; 0.98 s(-)(1). kPa(-)(1)). There was a trend toward a lower V max(FRC) (95% CI: -2; 67 ml/s(-)(1) in the CM group. In addition to providing a survival advantage, ECMO did not worsen lung function in infants assigned to receive it. Indeed, their lung function appeared slightly better than that of infants treated conventionally.

Respiratory failure: current status of experimental therapies

A number of advances in the treatment of infants and children with respiratory failure have been investigated in the laboratory with translation to clinical practice. Investigators have recognized that application of high ventilating pressures and failure to apply adequate levels of positive end-expiratory pressure (PEEP) can inflict injury to the already failing lung. Other interventions such as prone positioning and application of new ventilating strategies such as proportional assist ventilation (PAV), inverse ratio ventilation (IRV), high frequency ventilation, liquid ventilation, and intratracheal pulmonary ventilation (ITPV), continue to be developed and explored. Administration of inhaled nitric oxide (iNO) may improve pulmonary physiology and gas exchange in patients with respiratory insufficiency. Finally, the technique of extracorporeal life support (ECLS) is being simplified and refined. This report summarizes the status of these advances and describes the basic science and clinical research that brought them to clinical application.

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.

Number and activation of circulating polymorphonuclear leukocytes and platelets are associated with neonatal respiratory distress syndrome severity

OBJECTIVE

To determine whether number and activation of circulating polymorphonuclear leukocytes (PMNs) and platelets are associated with disease severity in neonatal respiratory distress syndrome (RDS).

DESIGN

Prospective study.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS

Preterm infants with severe (n = 18) or mild to moderate (n = 18) RDS who were consecutively admitted.

INTERVENTIONS

PMN and platelet counts and plasma concentrations of elastase-alpha1-proteinase inhibitor (E-alpha1-PI) and thromboxane B2 (TxB2) were recorded each day during the first 5 days of life. E-alpha1-PI-to-PMN and TxB2-to-platelet ratios were calculated to correct for the influence of the PMN and platelet count on elastase and thromboxane release.

RESULTS

From day 2, the severe RDS group had lower median PMN counts (1.5 vs 4.5 x 10/L), lower mean platelet counts (136 vs 230 x 10/L), and more elastase and thromboxane release, indicated by higher median E-alpha1-PI-to-PMN (39.2 vs 13.0 ng/10 PMNs on day 2) and TxB2-to-platelet (2.61 vs 0.52 pg/10 platelets on day 3) ratios than the mild-to-moderate group. Lower PMN and platelet counts and higher elastase and thromboxane release were correlated with birth asphyxia (lower 5-minute Apgar scores and umbilical arterial PH values), higher respiratory requirements (fraction of inspired oxygen and peak inspiratory pressure), and decreased values for continuous measures of RDS severity (ventilatory efficiency index and PaO2-to-alveolar oxygen tension ratio).

CONCLUSION

Decreased PMN and platelet counts and increased elastase and thromboxane release are correlated with increased RDS severity. Birth asphyxia (hypoxia and acidosis) and tissue injury caused by high-pressure ventilation and hyperoxia may promote this activation process.

Novel therapies for acute respiratory failure

Mortality in acute respiratory failure in the non-neonatal pediatric patient has not changed substantially in 20 years, despite advances and refinements in conventional therapeutic strategies and technology. A host of innovative therapies are currently in various stages of investigation, including high frequency ventilation, pressure control ventilation, permissive hypercapnia, extracorporeal membrane oxygenation, exogenous surfactant administration, inhaled nitric oxide, and liquid ventilation. While none of these therapies has yet been prospectively studied in non-neonatal pediatric patients, all show much promise by virtue of their emphasis on either directly addressing pathophysiologic derangements associated with acute respiratory failure or by reducing the complications associated with conventional therapy.

Neonatal extracorporeal membrane oxygenation (ECMO): clinical trials and the ethics of evidence

Neonatal extracorporeal membrane oxygenation (ECMO), a technology for the treatment of respiratory failure in newborns, is used as a case study to examine statistical and ethical aspects of clinical trials and to illustrate a proposed 'ethics of evidence', an approach to medical uncertainty within the context of contemporary biomedical ethics. Discussion includes the twofold aim of the ethics of evidence: to clarify the role of uncertainty and scientific evidence in medical decision-making, and to call attention to the need to confront the irreducible nature of uncertainty.

Advances in the treatment of persistent pulmonary hypertension of the newborn

Despite an association with meconium and blood aspiration, pneumonia, sepsis, pneumothorax, prematurity, and congenital diaphragmatic hernia, no cause for persistent pulmonary hypertension of the newborn can be found in many cases. This article discusses the advances in current therapies including the promising new therapy of inhaled nitric oxide.

Extracorporeal membrane oxygenation: support for overwhelming pulmonary failure in the pediatric population. Collective experience from the extracorporeal life support organization

Data from the Extracorporeal Life Support Organization (ELSO) regarding the use of extracorporeal membrane oxygenation (ECMO) in pediatric patients with respiratory failure are reviewed. Two hundred eighty-five children between the ages of 14 days and 18 years were supported with ECMO between January 1982 and September 1991. Although these data represent the experience of 52 ECMO centers, seven centers accounted for over 50% of the total. The patients had a mean age of 33 +/- 48 months with a median age of 13 months: 137 (48%) were male and 148 (52%) were female. There were numerous primary pulmonary diagnoses: the two most common were presumed viral pneumonia (32%) and adult respiratory distress syndrome (28%). Entry criteria for ECMO, although poorly defined and specific to each institution, attempted to identify children with an 85% to 100% predicted mortality. The survival rate with ECMO was 47% (135/285). Pre-ECMO mechanical ventilatory support was extreme with an FIO2 .97 +/- .07 and a mean airway pressure (MAP) 23.6 +/- 8 cm H2O used to achieve PaO2 of 50 +/- 39 and PaCO2 51 +/- 22 mm Hg. The MAP was significantly higher in nonsurvivors versus survivors (25.3 +/- 8.7 v 22.0 +/- 7.1 cm H2O, P < .01). The duration of ECMO was 4 hours to 35.5 days with a mean of 245 +/- 165 hours, which is approximately 10 days. Duration for survivors was 222 +/- 151 hours compared with 266 +/- 176 hours for nonsurvivors. ECMO complications are divided into two categories: mechanical (directly related to the ECMO circuit) and medical (patient related).(ABSTRACT TRUNCATED AT 250 WORDS)

Uses of extracorporeal membrane oxygenation in nonneonatal respiratory patients. An update

Neonatal extracorporeal membrane oxygenation (ECMO) has progressed rapidly from the experimental stage to a standard of care for certain infants who fail to respond to maximal conventional management. A broad diagnostic group of nonneonatal patients has now been supported by several different modes of ECMO with encouraging results. Selection criteria for nonneonatal patients that differ from those used for neonatal patients are emerging. Prospective randomized clinical trials are needed.

Mortality prediction in infants with congenital diaphragmatic hernia: potential criteria for ECMO

Over the last ten years the survival of infants born with congenital diaphragmatic hernia who reach the Intensive Care Unit of the Royal Children's Hospital, Melbourne has been constant at 56 +/- 6%. Experimental therapies such as extracorporeal membrane oxygenation, high-frequency oscillation and lung transplantation are now being considered as therapeutic options, and as such the ability to predict survival or death of these infants is increasingly important. The records of all infants with congenital diaphragmatic hernia admitted to the Intensive Care Unit between 1 January 1980 and 30 April 1989 were reviewed; blood gas, ventilatory details, and outcome information was obtained. Receiver operating curve analysis was used to determine the best predictor of death. An oxygenation index (MAP x FiO2/PaO2) > 0.3 or ventilation index (PIP x RR x CO2/1000) > 70 predicted a 94% mortality with a specificity of 96% and a sensitivity of 82%.

Experience with extracorporeal membrane oxygenation in children more than one month old

Extracorporeal membrane oxygenation (ECMO) has been used at the Royal Children's Hospital, Melbourne, in the treatment of children with life-threatening respiratory or cardiac failure since May 1988. The main indications for its use are, first, the disease is thought to be reversible, second, the child will survive with an acceptable quality of life and, third, the child has an 80% chance of dying without ECMO. Seven of eighteen children receiving ECMO have survived to leave hospital, and all are functionally normal: these results are similar to international results. It would appear that ECMO is a useful therapy for some children with otherwise fatal cardiorespiratory failure.