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

Use of surfactant beyond respiratory distress syndrome, what is the evidence?

Surfactant replacement therapy is currently approved by the United States Food and Drug Administration (FDA) for premature infants with respiratory distress syndrome (RDS) caused by surfactant deficiency due to immaturity. There is strong evidence that surfactant decreases mortality and air leak syndromes in premature infants with RDS. However, surfactant is also used "off-label" for respiratory failure beyond classic RDS. This review discusses current evidence for the use of off-label surfactant therapy for (1) term infants with lung disease such as meconium aspiration syndrome (MAS), pneumonia/sepsis, and congenital diaphragmatic hernia (2) premature infants after 72 h for acute respiratory failure, and (3) the use of surfactant lavage. At last, we briefly describe the use of surfactants for drug delivery and the current evidence on evaluating infants for surfactant deficiency.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Evidence-Based Guidelines for Acute Stabilization and Management of Neonates with Persistent Pulmonary Hypertension of the Newborn

Persistent pulmonary hypertension of the newborn, or PPHN, represents a challenging condition associated with high morbidity and mortality. Management is complicated by complex pathophysiology and limited neonatal specific evidence-based literature, leading to a lack of universal contemporary clinical guidelines for the care of these patients. To address this need and to provide consistent high-quality clinical care for this challenging population in our neonatal intensive care unit, we sought to develop a comprehensive clinical guideline for the acute stabilization and management of neonates with PPHN. Utilizing cross-disciplinary expertise and incorporating an extensive literature search to guide best practice, we present an approachable, pragmatic, and clinically relevant guide for the bedside management of acute PPHN. KEY POINTS: · PPHN is associated with several unique diagnoses; the associated pathophysiology is different for each unique diagnosis.. · PPHN is a challenging, dynamic, and labile process for which optimal care requires frequent reassessment.. · Key management goals are adequate tissue oxygen delivery, avoiding harm..

Extracorporeal Membrane Oxygenation Then and Now; Broadening Indications and Availability

Extracorporeal membrane oxygenation (ECMO) is a life support technology provided to children to support respiratory failure, cardiac failure, or cardiopulmonary resuscitation after failure of conventional management. Over the decades, ECMO has expanded in use, advanced in technology, shifted from experimental to a standard of care, and evidence supporting its use has increased. The expanded ECMO indications and medical complexity of children have also necessitated focused studies in the ethical domain such as decisional authority, resource allocation, and equitable access.

Extracorporeal Membrane Oxygenation (ECMO) and its complications in newborns with congenital diaphragmatic hernia

BACKGROUND

Extracorporeal Membrane Oxygenation (ECMO) is offered to patients with congenital diaphragmatic hernia (CDH) who are in severe respiratory and cardiac failure. We aim to describe the types of complications among these patients and their impact on survival.

METHODS

A single-center, retrospective review of CDH patients cannulated onto ECMO between January 2005 and November 2020 was conducted. ECMO complications, as categorized by the Extracorporeal Life Support Organization (ELSO), were correlated with survival status. Descriptive statistics were used to compare observed complications between survivors and non-survivors.

RESULTS

In our cohort of CDH neonates, 21% (54/258) were supported with ECMO, of whom, 61% (33/54) survived. Survivors and non-survivors were similar in baseline characteristics except for birthweight z-score (p = 0.043). Seventy percent of CDH neonates experienced complications during their ECMO run, with the most common categories being metabolic (48.1%) and mechanical (38.9%), followed by hemorrhage (22.2%), neurological (18.5%), renal (11.1%), pulmonary (7.4%), and cardiovascular (7.4%). The median number of complications per patient was higher in the non-survivor group  (2 (IQR: 1-4) vs 1 (IQR: 0-2), p = 0.043). In addition, mechanical (57.1% vs 27.3%, p = 0.045) and renal (28.6% vs 0%, p = 0.002) complications were more common among non-survivors compared to survivors.

CONCLUSION

Complications occur frequently among ECMO-treated newborns with CDH, some of which have serious long-term consequences. Survivors had higher birth weight z-scores, shorter ECMO runs, and fewer complications per patient. Mechanical and renal complications were independently associated with mortality, emphasizing the utility of more focused strategies to target fluid balance and renal protection and to prevent circuit and cannula complications.

Use of vasopressin in persistent pulmonary hypertension of the newborn: A case series

Treatment of neonates with persistent pulmonary hypertension of newborn includes optimization of ventilatory support, use of pulmonary vasodilators, and/or inotropic support. If refractory to this management, some may require extracorporeal membrane oxygenation. We describe a case series of 10 neonates with refractory persistent pulmonary hypertension of newborn treated with vasopressin in a single tertiary center. Mean initiation time of vasopressin was at 30 h of life with a dose ranging from 10 to 85 milliunits/kg/h. Oxygenation index decreased after 12 h of vasopressin exposure (25 to 11) and mean arterial pressure improved after 1 h (45 to 58 mm Hg). Extracorporeal membrane oxygenation was averted in 50% of the cases with transient hyponatremia as the only notable side effect. Although our findings are exploratory and further research is needed to establish safety and efficacy, our experience suggests that vasopressin may have rescue properties in the management of refractory persistent pulmonary hypertension of newborn.

Neonatal respiratory and cardiac ECMO in Europe

Neonatal extracorporeal membrane oxygenation (ECMO) is a life-saving procedure for critically ill neonates suffering from a potentially reversible disease, causing severe cardiac and/or respiratory failure and refractory to maximal conventional management. Since the 1970s, technology, management, and clinical applications of neonatal ECMO have changed. Pulmonary diseases still represent the principal neonatal diagnosis, with an overall 74% survival rate, and up to one-third of cases are due to congenital diaphragmatic hernia. The overall survival rate in cardiac ECMO is lower, with congenital heart defect representing the main indication. This review provides an overview of the available evidence in the field of neonatal ECMO. We will address the changing epidemiology, basic principles, technologic advances in circuitry, and monitoring, and deliver a current multidisciplinary management framework, focusing on ECMO applications, complications, and long-term morbidities. Lastly, areas for further research will be highlighted.Conclusions: ECMO is a life support with a potential impact on long-term patients' outcomes. In the next years, advances in knowledge, technology, and expertise may push neonatal ECMO boundaries towards more premature and increasingly complex infants, with the final aim to reduce the burden of ECMO-related complications and improve overall patients' outcomes. What is Known: • ECMO is a life-saving option in newborns with refractory respiratory and/or cardiac failure. • The multidisciplinary ECMO management is challenging and may expose neonates to complications with an impact on long-term outcomes. What is New: • Advances in technology and biomaterials will improve neonatal ECMO management and, eventually, the long-term outcome of these complex patients. • Experimental models of artificial placenta and womb technology are under investigation and may provide clinical translation and future research opportunities.

Complications and mortality of venovenous extracorporeal membrane oxygenation in the treatment of neonatal respiratory failure: a systematic review and meta-analysis

Background

Extracorporeal membrane oxygenation (ECMO) has been increasingly used for severe neonatal respiratory failure refractory to conventional treatments. To systematically evaluate the complications and mortality of venovenous ECMO (VV ECMO) in the treatment of neonatal respiratory failure, we performed a systematic review and meta-analysis of all the related studies.

Methods

PubMed, Embase, and Cochrane Library were searched. The retrieval period was from the establishment of the database to February 2019. Two investigators independently screened articles according to the inclusion and exclusion criteria. The quality of article was assessed by the Newcastle-Ottawa scale (NOS). The meta-analysis was performed by Stata 15.0 software.

Results

Four observational studies were included, with a total of 347 newborns. VV ECMO was used for neonates with refractory respiratory failure unresponsive to maximal medical therapy. Median ages of the newborns at cannulation were 43.2 h, 23 h, 19 h, and 71 h in the included four studies, respectively. The overall mortality at hospital charge was 12% (5–18%) with a heterogeneity of I² = 73.8% (p = 0.01). Two studies reported mortality during ECMO and after decannulation, with 10% (0.8–19.2%) and 6.1% (2.6–9.6%), respectively. The most common complications associated with VV ECMO were: pneumothorax (20.6%), hypertension (20.4%), cannula dysfunction (20.2%), seizure (14.9%), renal failure requiring hemofiltration (14.7%), infectious complications (10.3%), thrombi (7.4%), intracranial hemorrhage or infarction (6.6%), hemolysis (5.3%), cannula site bleeding (4.4%), gastrointestinal bleeding (3.7%), oxygenator failure (2.8%), other bleeding events (2.8%), brain death (1.9%), and myocardial stun (0.9%).

Conclusion

The overall mortality at discharge of VV ECMO in the treatment of neonatal respiratory failure was 12%. Although complications are frequent, the survival rate during hospitalization is still high. Further larger samples, and higher quality of randomized controlled trials (RCTs) are needed to clarify the efficacy and safety of this technique in the treatment of neonatal respiratory failure.

Use of high frequency oscillatory ventilator in neonates with respiratory failure: the clinical practice in Taiwan and early multimodal outcome prediction

High-frequency oscillatory ventilation (HFOV) can be a rescue for neonates with refractory respiratory failure or an early elective therapy for preterm infants with severe respiratory distress syndrome (RDS). However, little is known about the current evolution and therapeutic limitations of HFOV. We therefore aimed to describe its use in clinical practice and predict the risk of mortality for neonates receiving HFOV. A retrospective observational study of all neonates treated with HFOV in a quaternary referral NICU between January 2007 and December 2016 was conducted. We classified these patients into five subgroups based on primary respiratory diagnoses. We performed the logistic regression and decision tree regression analyses to identify independent factors of 30-day mortality following HFOV. A total of 1125 patients who were ever supported on HFOV were enrolled, of whom 64.1% received HFOV as a rescue therapy, 27.2% received it as an elective therapy, and 8.7% received it for air leak. An average oxygenation index (OI) greater than 25 in the first 24 hours after the initiation of HFOV and patients with secondary pulmonary hypertension were found to have the greatest risk of in-hospital mortality (p < 0.0001). The overall in-hospital mortality rate was 25.8% (290/1125). Decision tree regression analysis revealed that neonates with refractory respiratory failure who had a pre-HFOV OI value higher than 20.5 and OI values higher than 21.5, 23.5 and 34 at 2 hours, 6 hours, and 12 hours after the use of HFOV, respectively, had a significantly increased risk of 30-day mortality. We identified the predictors and cutoff points of OI before and after the initiation of HFOV in neonates with respiratory failure, which can be clinically used as a reference for 30-day mortality. Further efforts are still needed to optimize the outcomes.

Neonatal respiratory extracorporeal membrane oxygenation and primary diagnosis: trends between two decades

OBJECTIVE

Examine changing neonatal respiratory extracorporeal membrane oxygenation (ECMO) practice trends and outcomes.

STUDY DESIGN

Retrospective cohort study comparing neonatal respiratory ECMO in the 1990 and 2010 decades (1994-1995 and 2014-2015). Patients ≤ 30 days of life, reported to the Extracorporeal Life Support Organization registry, were included.

RESULTS

Four thousand one hundred and twenty-five patients met inclusion criteria. ECMO cases decreased by 33%. The primary ECMO diagnosis changed significantly over time (p < 0.0001). Survival to discharge decreased (76 vs 67%, p < 0.0001) and ECMO duration increased (131 vs 158 h, p < 0.001). Lung recovery was the most common reason to discontinue ECMO although family request for withdrawal and a diagnosis considered "incompatible with life" was increasingly common in the 2010s.

CONCLUSION

Although the use of ECMO for neonatal respiratory diagnoses has decreased over time, its use has increased for patients with more complex diagnoses and ECMO duration is longer. ECMO continues to be an important supportive therapy, improved understanding of which patients would benefit most is needed.

Updates in Pediatric Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation is an increasingly used mode of life support for patients with cardiac and/or respiratory failure refractory to conventional therapy. This review provides a synopsis of the evolution of extracorporeal life support in neonates, infants, and children and offers a framework for areas in need of research. Specific aspects addressed are the changing epidemiology; technologic advancements in extracorporeal membrane oxygenation circuitry; the current status and future direction of anticoagulation management; sedative and analgesic strategies; and outcomes, with special attention to the lessons learned from neonatal survivors.

The Role of Echocardiography in Neonates and Pediatric Patients on Extracorporeal Membrane Oxygenation

Indications for extracorporeal membrane oxygenation (ECMO) and extracorporeal cardiopulmonary resuscitation (ECPR) are expanding, and echocardiography is a tool of utmost importance to assess safety, effectiveness and readiness for circuit initiation and separation. Echocardiography is key to anticipating complications and improving outcomes. Understanding the patient's as well as the ECMO circuit's anatomy and physiology is crucial prior to any ECMO echocardiographic evaluation. It is also vital to acknowledge that the utility of echocardiography in ECMO patients is not limited to the evaluation of cardiac function, and that clinical decisions should not be made exclusively upon echocardiographic findings. Though echocardiography has specific indications and applications, it also has limitations, characterized as: prior to and during cannulation, throughout the ECMO run, upon separation and after separation from the circuit. The use of specific and consistent echocardiographic protocols for patients on ECMO is recommended.

Is Extracorporeal Membrane Oxygenation for a Neonate Ever Ethically Obligatory?

Certain interventions in the neonatal intensive care unit are considered ethically obligatory, and should be provided over parental objections. After reviewing a case, comparative outcome data, and relevant ethical principles, we propose that extracorporeal membrane oxygenation for meconium aspiration syndrome may, in some cases, be an ethically obligatory treatment.

Current trends in neonatal ECMO

Extracorporeal membrane oxygenation (ECMO) is a life-saving therapy for patients with respiratory and cardiac failure refractory to maximal medical management. The extracorporeal life support organization registry is the largest available resource for describing the population and outcomes of patients treated with this therapy. The use of ECMO for neonatal patients is decreasing in proportion to the total annual ECMO runs most likely due to advancements in medical management. Although the overall survival for neonatal ECMO has decreased, this is likely a reflection of the increasingly complex neonatal patients treated with this therapy. Although many patient and mechanical complications are decreasing over time, there remains a high percentage of morbidities and risks associated with ECMO. Continued refinements in management strategies are important to improving overall patient outcomes.

Shifting Risks and Conflicting Outcomes-ECMO for Neonates with Congenital Diaphragmatic Hernia in the Modern Era

OBJECTIVES

To update previously described trends for neonates with congenital diaphragmatic hernia (CDH) receiving ECMO with changes in recommendations for care, and to determine how recent advancements in respiratory care have affected this patient population.

STUDY DESIGN

This study is a retrospective review of more than 2500 neonates with CDH who received ECMO listed in the Extracorporeal Life Support Organization (ELSO) registry. Cochran-Armitage and multivariate regression analyses were used to analyze changes in the patient population over time and in mortality-related risk factors.

RESULTS

Almost one-half (48.1%) of the term neonates survived to discharge, representing a 13.8% decline in survival over the past 25 years (P < .0001). Over the past 10 years, the prevalence of respiratory acidosis more than doubled (P < .0001) and the prevalence of major complications increased (P < .001). During the same period, the number of ECMO courses longer than 1 week increased (P < .001), whereas the prevalence of multiple complications (>4) decreased (P < .0001). Surgeries performed on ECMO were associated with worse outcomes than those performed off ECMO. ECMO duration no longer represents a mortality-related risk factor.

CONCLUSIONS

Survival rates for neonates with CDH receiving ECMO have continued to drop in the modern era. Although the safety of ECMO has improved over the last decade, the number of patients experiencing significant respiratory acidosis has more than doubled-increasing the risk of intracranial hemorrhage and overall mortality. The evidence for permissive hypercapnia remains mixed; nonetheless, we believe that the risks outweigh the rewards in this patient population.

Lung Rest During Extracorporeal Membrane Oxygenation for Neonatal Respiratory Failure-Practice Variations and Outcomes

OBJECTIVE

Describe practice variations in ventilator strategies used for lung rest during extracorporeal membrane oxygenation for respiratory failure in neonates, and assess the potential impact of various lung rest strategies on the duration of extracorporeal membrane oxygenation and the duration of mechanical ventilation after decannulation.

DATA SOURCES

Retrospective cohort analysis from the Extracorporeal Life Support Organization registry database during the years 2008-2013.

STUDY SELECTION

All extracorporeal membrane oxygenation runs for infants less than or equal to 30 days of life for pulmonary reasons were included.

DATA EXTRACTION

Ventilator type and ventilator settings used for lung rest at 24 hours after extracorporeal membrane oxygenation initiation were obtained.

DATA SYNTHESIS

A total of 3,040 cases met inclusion criteria. Conventional mechanical ventilation was used for lung rest in 88% of cases and high frequency ventilation was used in 12%. In the conventional mechanical ventilation group, 32% used positive end-expiratory pressure strategy of 4-6 cm H2O (low), 22% used 7-9 cm H2O (mid), and 43% used 10-12 cm H2O (high). High frequency ventilation was associated with an increased mean (SEM) hours of extracorporeal membrane oxygenation (150.2 [0.05] vs 125 [0.02]; p < 0.001) and an increased mean (SEM) hours of mechanical ventilation after decannulation (135 [0.09] vs 100.2 [0.03]; p = 0.002), compared with conventional mechanical ventilation among survivors. Within the conventional mechanical ventilation group, use of higher positive end-expiratory pressure was associated with a decreased mean (SEM) hours of extracorporeal membrane oxygenation (high vs low: 136 [1.06] vs 156 [1.06], p = 0.001; mid vs low: 141 [1.06] vs 156 [1.06]; p = 0.04) but increased duration of mechanical ventilation after decannulation in the high positive end-expiratory pressure group compared with low positive end-expiratory pressure (p = 0.04) among survivors.

CONCLUSIONS

Wide practice variation exists with regard to ventilator settings used for lung rest during neonatal respiratory extracorporeal membrane oxygenation. Use of high frequency ventilation when compared with conventional mechanical ventilation and use of low positive end-expiratory pressure strategy when compared with mid positive end-expiratory pressure and high positive end-expiratory pressure strategy is associated with longer duration of extracorporeal membrane oxygenation. Further research to provide evidence to drive optimization of pulmonary management during neonatal respiratory extracorporeal membrane oxygenation is warranted.

Extracorporeal Life Support: Four Decades and Counting

Extracorporeal membrane oxygenation (ECMO) or extracorporeal life support (ECLS) is a form of heart lung bypass that is used to support neonates, pediatrics, and adult patients with cardiorespiratory failure for days or weeks till organ recovery or transplantation. Venoarterial (VA) and venovenous (VV) ECLS are the most common modes of support. ECLS circuit components and monitoring have been evolving over the last 40 years. The technology is safer, simpler, and more durable with fewer complications. The use of neonatal respiratory ECLS use has been declining over the last two decades, while adult respiratory ECLS is growing especially since the H1N1 influenza pandemic in 2009. This review provides an overview of ECLS evolution over the last four decades, its use in neonatal, pediatric and adults, description of basic principles, circuit components, complications, and outcomes as well as a quick look into the future.

Extracorporeal Life Support in Pediatric and Neonatal Critical Care: A Review

Extracorporeal life support (ECLS) is a modified form of cardiopulmonary bypass used to provide prolonged tissue oxygen delivery in patients with respiratory and/or cardiac failure. The first large-scale success of ECLS was achieved in the management of term newborns with respiratory failure. ECLS has become an accepted therapeutic modality for neonates, children, and adults who have failed conventional therapy and in whom cardiac and/or respiratory insufficiency is potentially reversible. The use of ECLS allows one to reduce other cardiopulmonary supports and apply a gentle ventilation strategy in a population of severely compromised critical care patients. ECLS has now been employed in more than 26,000 neonatal and pediatric patients with an overall survival rate of 68%. ECLS has evolved significantly over 25 years of clinical practice; patient selection for this complex and highly invasive therapy, as well as how ECLS is employed in different patient groups, is constantly changing. Generally, ECLS is used more liberally now than in the past. The number of patients requiring this support, however, is declining yearly, and those patients who receive ECLS compose a more severe subset of an intensive care population. This review provides an overview of the development of ECLS and the equipment and techniques employed. The use of ECLS for neonatal respiratory failure, pediatric respiratory failure, and cardiac support are outlined. Management of the ECLS patient is discussed in detail, and outcome of these patients is reviewed. Finally, current trends and future implications of ECLS in neonatal and pediatric critical care are addressed.

Pulmonary Hypertension and Pulmonary Vasodilators

Pulmonary hypertension in the perinatal period can present acutely (persistent pulmonary hypertension of the newborn) or chronically. Clinical and echocardiographic diagnosis of acute pulmonary hypertension is well accepted but there are no broadly validated criteria for echocardiographic diagnosis of pulmonary hypertension later in the clinical course, although there are significant populations of infants with lung disease at risk for this diagnosis. Contributing cardiovascular comorbidities are common in infants with pulmonary hypertension and lung disease. It is not clear who should be treated without confirmation of pulmonary vascular disease by cardiac catheterization, with concurrent evaluation of any contributing cardiovascular comorbidities.

Neonatal Respiratory Diseases in the Newborn Infant: Novel Insights from Stable Isotope Tracer Studies

Respiratory distress syndrome is a common problem in preterm infants and the etiology is multifactorial. Lung underdevelopment, lung hypoplasia, abnormal lung water metabolism, inflammation, and pulmonary surfactant deficiency or disfunction play a variable role in the pathogenesis of respiratory distress syndrome. High-quality exogenous surfactant replacement studies and studies on surfactant metabolism are available; however, the contribution of surfactant deficiency, alteration or dysfunction in selected neonatal lung conditions is not fully understood. In this article, we describe a series of studies made by applying stable isotope tracers to the study of surfactant metabolism and lung water. In a first set of studies, which we call 'endogenous studies', using stable isotope-labelled intravenous surfactant precursors, we showed the feasibility of measuring surfactant synthesis and kinetics in infants using several metabolic precursors including plasma glucose, plasma fatty acids and body water. In a second set of studies, named 'exogenous studies', using stable isotope-labelled phosphatidylcholine tracer given endotracheally, we could estimate surfactant disaturated phosphatidylcholine pool size and half-life. Very recent studies are focusing on lung water and on the endogenous biosynthesis of the surfactant-specific proteins. Information obtained from these studies in infants will help to better tailor exogenous surfactant treatment in neonatal lung diseases.

Diverse Morbidity and Mortality Among Infants Treated with Venoarterial Extracorporeal Membrane Oxygenation

Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is utilized for cardiopulmonary failure. We aimed to qualify and quantify the predictors of morbidity and mortality in infants requiring VA-ECMO.

Methods: Data was collected from 170 centers participating in the extracorporeal life support organization (ELSO) registry. Relationships between in-hospital mortality and risk factors were assessed using logistic regression. Survival was defined as being discharged from the hospital.

Results: Six hundred and sixty-two eligible records were reviewed. Mortality occurred in 303 (46%) infants. Congenital diaphragmatic hernia patients (OR=3.83, 95% CI 1.96-7.49, p<0.001), cardiac failure with associated shock (OR= 2.90, 95% CI 1.46-5.77, p=0.002), and pulmonary failure including respiratory distress syndrome (OR=4.06, 95% CI 1.72-9.58, p=0.001) had the highest odds of mortality in this cohort. Birth weight (BW) < 3 kg (OR=1.83, 95% CI 1.21-2.78, p=0.004), E-CPR (OR=3.35, 95% CI 1.57-7.15, p=0.002), hemofiltration (OR=2.04, 95% CI 1.32-3.16, p=0.001), and dialysis (OR=6.13, 95% CI 1.70-22.1, p<0.001) were all independent predictors of mortality.

Conclusion: Infants requiring VA-ECMO experience diverse sequelae and their mortality are high.

Extracorporeal life support: experience with 2,000 patients

This is a review of the University of Michigan experience with extracorporeal life support (ECLS) also known as extracorporeal membrane oxygenation (ECMO). Two thousand patients were managed with ECMO from 1973 to 2010. The first 1,000 patients were reported previously. Of the 2,000 patients, 74% were weaned from ECLS, and 64% survived to hospital discharge. In patients with respiratory failure, survival to hospital discharge was 84% in 799 neonates, 76% in 239 children, and 50% in 353 adults. Survival in patients with cardiac failure was 45% in 361 children and 38% in 119 adults. ECLS during extracorporeal cardiopulmonary resuscitation was performed in 129 patients, with 41% surviving to discharge. Survival decreased from 74 to 55% between the first and second 1,000 patients. The most common complication was bleeding at sites other than the head, with an incidence of 39%, and the least frequent complication was pump malfunction, with a 2% incidence. Intracranial bleeding or infarction occurred in 8% of patients, with a 43% survival rate. This is the largest series of ECLS at one institution reported in the world to date. Our experience has shown that ECLS saves lives of moribund patients with acute pulmonary and cardiac failure in all age groups.

Are All Oscillators Created Equal? In vitro Performance Characteristics of Eight High-Frequency Oscillatory Ventilators

BACKGROUND

The mode of waveform generation and circuit characteristics differ between high-frequency oscillators. It is unknown if this influences performance.

OBJECTIVES

To describe the relationships between set and delivered pressure amplitude (x0394;P), and the interaction with frequency and endotracheal tube (ETT) diameter, in eight high-frequency oscillators.

METHODS

Oscillators were evaluated using a 70-ml test lung at 1.0 and 2.0 ml/cm H2O compliance, with mean airway pressures (PAW) of 10 and 20 cm H2O, frequencies of 5, 10 and 15 Hz, and an ETT diameter of 2.5 and 3.5 mm. At each permutation of PAW, frequency and ETT, the set x0394;P was sequentially increased from 15 to 50 cm H2O, or from 20 to 100% maximum amplitude (10% increments) depending on the oscillator design. The x0394;P at the ventilator (x0394;PVENT), airway opening (x0394;PAO) and within the test lung (x0394;PTRACH), and tidal volume (V(T)) at the airway opening were determined at each set x0394;P.

RESULTS

In two oscillators the relationships between set and delivered x0394;P were non-linear, with a plateau in x0394;P thresholds noted at all frequencies (Dräger Babylog 8000) or ≥10 Hz (Dräger VN500). In all other devices there was a linear relationship between x0394;PVENT, x0394;PAO and x0394;PTRACH (all r2 >0.93), with differing attenuation of the pressure wave. Delivered V(T) at the different settings tested varied between devices, with some unable to deliver V(T) >3 ml at 15 Hz, and others generating V(T)>20 ml at 5 Hz and a 1:1 inspiratory-to-expiratory time ratio.

CONCLUSIONS

Clinicians should be aware that modern high-frequency oscillators exhibit important differences in the delivered x0394;P and V(T).

Acute Neonatal Respiratory Failure

Acute respiratory failure requiring assisted ventilation is one of the most common reasons for admission to the neonatal intensive care unit. Respiratory failure is the inability to maintain either normal delivery of oxygen to the tissues or normal removal of carbon dioxide from the tissues. It occurs when there is an imbalance between the respiratory workload and ventilatory strength and endurance. Definitions are somewhat arbitrary but suggested laboratory criteria for respiratory failure include two or more of the following: PaCO₂ > 60 mmHg, PaO₂ < 50 mmHg or O₂ saturation <80 % with an FiO₂ of 1.0 and pH < 7.25 (Wen et al. 2004).

Prolonged extracorporeal membrane oxygenator support among neonates with acute respiratory failure: a review of the Extracorporeal Life Support Organization registry

The objective of this study was to identify types of neonatal diseases associated with prolonged (≥21 days) extracorporeal membrane oxygenation (ECMO), characteristics of survivors and nonsurvivors among those requiring prolonged ECMO, and factors associated with mortality. Data were obtained from the Extracorporeal Life Support Organization registry over the period from January 1, 1998, through December 31, 2011, for all neonates (age <31 days), with respiratory failure as the indication for ECMO. The primary outcome was survival to hospital discharge. Survivors and nonsurvivors were compared for 1) patient demographics, 2) primary diagnosis, 3) pre-ECMO clinical course and therapies, and 4) ECMO course and associated complications. The most common diagnosis associated with prolonged ECMO support in neonates is congenital diaphragmatic hernia (CDH; 69%). Infants with meconium aspiration syndrome had the highest survival rate (71%) compared with other diagnoses analyzed (26.3%; p < 0.001). Nonsurvivors were more likely to experience complications on ECMO, and multivariate analysis showed that the need for inotropes while on ECMO support (odds ratio, 2.2 [95% confidence interval, 1.3-3.7]; p = 0.003) was independently associated with mortality. Neonates requiring prolonged ECMO support have a 24% survival to discharge. Many of these cases involve CDH. Complications are common with prolonged ECMO, but only receipt of inotropes was shown to be independently associated with mortality. This report may help guide clinical decision making and family counseling for neonates requiring prolonged ECMO support.

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.

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.

Vasopressin as a rescue therapy for refractory pulmonary hypertension in neonates: case series

OBJECTIVES

To determine the effect of vasopressin therapy on the efficacy of oxygenation and arterial pressure in infants with severe persistent pulmonary hypertension of the newborn.

DESIGN

Retrospective case study.

SETTING

Neonatal ICU, Hospital for Sick Children, Toronto, Canada.

SUBJECTS

Neonates with severe persistent pulmonary hypertension.

INTERVENTION

Intravenous infusion of vasopressin.

MEASUREMENTS AND MAIN RESULTS

Ten infants satisfied the inclusion criteria. Inhaled nitric oxide was used for median (interquartile range) duration of 15 hours (11-28 hr) prior to vasopressin commencement. Vasopressin was initiated at a mean dose of 0.0002 ± 0.0002 U/kg/min for a median (interquartile range) duration of 49 hours (13-95 hr). Administration of vasopressin was associated with an improvement in oxygenation index, peak effect 6 hours after drug initiation (p = 0.01), and a reduction in inhaled nitric oxide dose (p < 0.05). There was a concomitant improvement in blood pressure (p < 0.05) and urine output (p < 0.05), without drop in the serum sodium level or worsening in serum lactate level.

CONCLUSIONS

Although there is limited experience of vasopressin use in persistent pulmonary hypertension of the newborn infants, our case series suggests it to be a potential adjunctive therapy for improving the efficacy of oxygenation and systemic hypotension. A prospective randomized trial is needed to confirm its efficacy and safety in the management of severe persistent pulmonary hypertension of the newborn.

The use of ECMO for persistent pulmonary hypertension of the newborn: a decade of experience

PURPOSE

Despite improvements in the management of persistent pulmonary hypertension of the newborn (PPHN), a number of infants with inadequate gas exchange are treated with extracorporeal membrane oxygenation (ECMO). The objectives of this study were to use the Extracorporeal Life Support Organization Registry to review the outcomes of neonates with PPHN receiving ECMO, and to identify pre-ECMO variables that may be associated with increased mortality.

MATERIALS AND METHODS

The study is a retrospective analysis of all patients with PPHN supported with ECMO and reported to the Extracorporeal Life Support Organization registry from 2000 to 2010. Prematurity was defined as <37 wk gestation. Univariate analysis was performed using Student's t-test or Fisher's exact test. Variables found to be statistically significant underwent multivariate analysis by logistic regression. Kaplan-Meier survival curves were generated to analyze the relationship between duration of ECMO support and patient survival.

RESULTS

A total of 1569 neonates with PPHN received ECMO support during the study period, at an average age of 3.1 d of life and for a duration of 6.9 d. Survival among neonates with PPHN receiving ECMO support was 81%, and those receiving support for 7, 10, 14, and 21 d survived at rates of 88%, 78%, 55%, and 25%, respectively. By logistic regression, prematurity (P < 0.01), pre-ECMO pH ≤7.2 (P = 0.02), pre-ECMO SaO(2) ≤65% (P = 0.01), and duration of ECMO ≥7 d (P < 0.001) were independent predictors of death in this group. An average of 2.2 complications occurred per patient, with cardiovascular, mechanical, and renal complications being the most common.

CONCLUSIONS

Neonates with PPHN have high survival rates with ECMO support. Prematurity, acidosis, and profound hypoxemia are independently associated with increased mortality. Furthermore, prolonged ECMO support (>7 d) is associated with a higher risk of mortality in this cohort than in patients supported for <1 wk.

Surfactant therapy for acute lung injury and acute respiratory distress syndrome

This article examines exogenous lung surfactant replacement therapy and its usefulness in mitigating clinical acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). Surfactant therapy is beneficial in term infants with pneumonia and meconium aspiration lung injury, and in children up to age 21 years with direct pulmonary forms of ALI/ARDS. However, extension of exogenous surfactant therapy to adults with respiratory failure and clinical ALI/ARDS remains a challenge. This article reviews clinical studies of surfactant therapy in pediatric and adult patients with ALI/ARDS, focusing on its potential advantages in patients with direct pulmonary forms of these syndromes.

A 20-year experience on neonatal extracorporeal membrane oxygenation in a referral center

OBJECTIVE

Advances in treatment of neonatal respiratory failure are responsible for a decline in the number of newborns treated with extracorporeal membrane oxygenation (ECMO). The aim of this study are to determine demographic changes, focusing on time of referral, diagnosis, and respiratory parameters in neonates put on ECMO.

DESIGN

Retrospective review.

SETTING

Tertiary ECMO center.

PATIENTS

A total of 321 neonates were treated with ECMO from January 1987 to December 2006.

RESULTS

Overall number of patients increased with every 5-year period, whereby congenital diaphragmatic hernia (CDH) was the most common diagnosis (53%), followed by meconium aspiration syndrome (MAS) (21%), sepsis and/or pneumonia (13%), and others such as persistent pulmonary hypertension of the newborn (PPHN), respiratory distress syndrome (RDS), or hypoplasia of the lung (13%). Worsening severity of illness as measured by ECMO duration and days on ventilator has to be stated for all diagnoses. Nevertheless, survival rate remained stable; both overall and diagnosis-specific mortality rates did not change significantly. Of all children, 67% survived to discharge or transfer, while best rates were seen for MAS (94%), followed by sepsis and/or pneumonia (69%), CDH (62%), and other diagnoses (43%). Concerning survival rate, no difference between inborn and outborn children occurred. However, between early- and late-referred children, a referral to the ECMO center during the first 24 h of life was associated with a significantly higher rate of survival (77% versus 54%, p = 0.0004), predominantly seen for CDH (67% versus 35%, p = 0.02).

CONCLUSION

We strongly recommend timely transfer to an ECMO center in patients with CDH who are at risk of circulatory failure.

Extracorporeal membrane oxygenation and term neonatal respiratory failure deaths in the United Kingdom compared with the United States: 1999 to 2005

OBJECTIVE

To compare national neonatal extracorporeal membrane oxygenation data and deaths from primary respiratory disorders of term neonates between the United Kingdom and the United States from 1999 to 2005.

DESIGN

Cross-sectional study.

SETTING

National data sets from the United Kingdom and the United States.

PATIENTS

Neonatal extracorporeal membrane oxygenation patients submitted to the Extracorporeal Life Support Organization Registry and national birth and death registrations.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Meconium aspiration syndrome was the most common indication for extracorporeal membrane oxygenation in the United Kingdom: 50.6% vs. 25.8% in the United States (p < .001). Congenital diaphragmatic hernia was most common indication for extracorporeal membrane oxygenation in the United States: 30.7% vs. 15.4% in the United Kingdom (p < .001).Extracorporeal membrane oxygenation use was greater in the United States than the United Kingdom: rate ratio, 1.81 (95%, confidence interval, 1.64, 2.00). The extracorporeal membrane oxygenation rate decreased over time in the United States (p < .001) but was unchanged for all diagnoses in the United Kingdom (p = .49). The rates of extracorporeal membrane oxygenation use for meconium aspiration syndrome were equivalent in both countries: rate ratio, 0.92 (95% confidence interval, 0.80, 1.07) but greater in the United States for congenital diaphragmatic hernia: rate ratio, 3.60, (95% confidence interval, 2.82, 4.66) and persistent pulmonary hypertension newborn: rate ratio, 4.67 (95% confidence interval, 3.33, 6.74).National neonatal death rates included nonextracorporeal membrane oxygenation + extracorporeal membrane oxygenation death. Meconium aspiration syndrome deaths were equivalent overall between the two countries: rate ratio, 0.99 (95% confidence interval, 0.77, 1.29), but decreased in the United States (p < .001) although not in the United Kingdom (p = .17). Congenital diaphragmatic hernia deaths were more prevalent in the United Kingdom than in the United States: rate ratio, 1.57 (95% confidence interval, 1.34, 1.84).

CONCLUSIONS

Extracorporeal membrane oxygenation is used more often in the United States: clinicians seem less willing to offer extracorporeal membrane oxygenation for persistent pulmonary hypertension of the newborn and congenital diaphragmatic hernia in the United Kingdom. In contrast to the United States, no reduction in either extracorporeal membrane oxygenation use or death due to meconium aspiration syndrome was observed in the United Kingdom. Early transfer to a tertiary center is recommended for term neonates with respiratory failure.

CONTEMPORARY NEONATAL INTENSIVE CARE MANAGEMENT IN CONGENITAL DIAPHRAGMATIC HERNIA: DOES THIS OBVIATE THE NEED FOR FETAL THERAPY?

The management of congenital diaphragmatic hernia (CDH) in the newborn infant has changed radically since the first successful outcomes were reported 60 years ago. Then it seemed a surgical problem with a surgical solution – do an operation, remove the intestines and solid viscera from the thoracic cavity, repair the defect and allow the lung to expand. CDH in that era was regarded as the quintessential neonatal surgical emergency. The expectation was that urgent surgery would result in improvement in lung function and oxygenation. That approach persisted up to the 1980s when it was realized that the problem was far more complex and involved both an abnormal pulmonary vascular bed as well as pulmonary hypoplasia. The use of systemically delivered pulmonary vasodilator therapy, principally tolazoline, became a focus of interest in the 1980s with small case reports and case series suggesting improved survival. In the 1990s, based on studies that showed worsening thoracic compliance and gas exchange following surgical repair, deferred surgery and pre-operative stabilization became the standard of care. At the same time extracorporeal membrane oxygenation (ECMO) was increasingly used either as part of pre-operative stabilization or as a rescue therapy after repair. Other centres chose to use high frequency oscillatory ventilation (HFOV). Despite all these innovations the survival in live born infants with CDH did not improve to more than 50% in large series published from high volume centres. However, in the past 10 years there has been an appreciable improvement in survival to the extent that many centres are now reporting survival rates of greater than 80%. Probably the biggest impact on this improvement has been the recognition of the role that ventilation induced lung injury plays in mortality and the need for ECMO rescue. This has ushered in an era of a lung protective or “gentle ventilation” strategy which has been widely adopted as a standard approach. While there have been these radical changes in postnatal management attempts have been made to improve outcome with prenatal interventions, starting with prenatal repair, which was abandoned because of preterm labour. More recently there has been increasing experience in the use of balloon occlusion of the trachea as a prenatal intervention strategy with patients being selected based on prenatal predictors of poor outcome. This approach can only be justified if those predictors can be validated and the outcomes (death or serious long term morbidity) can be shown to be better than those currently achievable, namely 80% survival in high volume CDH centres rather than the 50–60% survival frequently quoted in historical papers.

Advances in the diagnosis and management of persistent pulmonary hypertension of the newborn

Rapid evaluation of a neonate who is cyanotic and in respiratory distress is essential for achieving a good outcome. Persistent pulmonary hypertension of the newborn (PPHN) can be a primary cause or a contributing factor to respiratory failure, particularly in neonates born at 34 weeks or more of gestation. PPHN represents a failure of normal postnatal adaptation that occurs at birth in the pulmonary circulation. Rapid advances in therapy in recent years have led to a remarkable decrease in mortality for the affected infants. Infants who survive PPHN are at significant risk for long-term hearing and neurodevelopmental impairments, however. This review focuses on the diagnosis, recent advances in management, and recommendations for the long-term follow-up of infants who have PPHN.

Pulmonary surfactant kinetics of the newborn infant: novel insights from studies with stable isotopes

Deficiency or dysfunction of the pulmonary surfactant plays a critical role in the pathogenesis of respiratory diseases of the newborn. After a short review of the pulmonary surfactant, including its role in selected neonatal respiratory conditions, we describe a series of studies conducted by applying two recently developed methods to measure surfactant kinetics. In the first set of studies, namely 'endogenous studies', which used stable isotope-labeled intravenous surfactant precursors, we have shown the feasibility of measuring surfactant synthesis and kinetics in infants using several metabolic precursors, including plasma glucose, plasma fatty acids and body water. In the second set of studies, namely 'exogenous studies', which used a stable isotope-labeled phosphatidylcholine (PC) tracer given endotracheally, we estimated the surfactant disaturated phosphatidylcholine (DSPC) pool size and half-life. The major findings of our studies are presented here and can be summarized as follows: (a) the de novo synthesis and turnover rates of the surfactant (DSPC) in preterm infants with respiratory distress syndrome (RDS) are very low with either precursor; (b) in preterm infants with RDS, pool size is very small and half-life much longer than what has been reported in animal studies; (c) patients recovering from RDS who required higher continuous positive airway pressure pressure after extubation or reintubation have a lower level of intrapulmonary surfactant than those who did well after extubation; (d) term newborn infants with pneumonia have greatly accelerated surfactant catabolism; and (e) infants with uncomplicated congenital diaphragmatic hernia (CDH) and on conventional mechanical ventilation have normal surfactant synthesis, but those requiring extracorporeal membrane oxygenated (ECMO) do not. Information obtained from these studies in infants will help to better tailor exogenous surfactant treatment in neonatal lung diseases.

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.

Predictors of outcome for children requiring respiratory extra-corporeal life support: implications for inclusion and exclusion criteria

OBJECTIVES

A range of children receive extra-corporeal life support (ECLS) for respiratory failure, but there is little published data on this group. Our aims were: (1) to analyse predictors of outcome and (2) comment on inclusion and exclusion criteria.

DESIGN

Retrospective review.

SETTING

Tertiary ECLS centre.

PATIENTS

A total of 124 children categorised as 'paediatric respiratory ECLS' from July 1992 to December 2005.

RESULTS

Fifty-three percent of children had one or more co-morbid conditions; the median age was 10.1 (IQR 3-34) months; the median ECLS duration was 9 (IQR 5-17) days; survival to discharge was 62% and at 1 year was 59%. Although survival varied according to primary reason for ECLS (range 36-100%), after adjustment for this, the presence of a co-morbid condition was unrelated to mortality (OR = 1.49, 95% CI 0.65, 3.42, P = 0.34) Predictors of mortality were increased pre-ECLS oxygenation index (OR = 1.09, 95% CI 1.00, 1.18, P = 0.05) and shock (OR 2.53, 95% CI 1.21, 5.28, P = 0.01). The relationship between mortality and end organ dysfunction (OR 2.12, 95% CI 0.89, 5.02, P = 0.09) and greater number of pre-ECLS ventilator days (OR 1.10, 95% CI 0.99, 1.22, P = 0.08) was less conclusive.

CONCLUSIONS

Pre-existing co-morbid conditions may predispose children to develop severe respiratory failure but with careful case selection, do not appear to reduce the chance of survival. Severity of pulmonary dysfunction determined by OI and shock were key predictors of outcome and should remain important determinants of referral for ECLS.

Neonatal extra-corporeal life support: indications and limitations

Cardiac extra-corporeal life support is used more frequently in the current era of complex, high-risk neonatal heart surgery. Although outcome for neonates with complex heart disease has improved in the last decade, thanks to advances in surgery and intensive care, survival in the subset that require extra-corporeal support remains unchanged at below 40%. Neonatal cardiac extra-corporeal support is a technically challenging therapy that is applied in a range of contexts including: post-operative low cardiac output syndrome, cardiac arrest, high-risk interventional catheterisation or as a bridge to recovery from dysrhythmia and myocarditis. Extra-corporeal life support has increased in particular for neonates with single ventricle disease in the last 5 years, mainly achieving similar results to biventricular patients. Further research is required in order to determine the optimal methods for patient selection and to establish important predictors of outcome including the longterm neurological development of survivors.

Surfactant-replacement therapy for respiratory distress in the preterm and term neonate

Respiratory failure secondary to surfactant deficiency is a major cause of morbidity and mortality in preterm infants. Surfactant therapy substantially reduces mortality and respiratory morbidity for this population. Secondary surfactant deficiency also contributes to acute respiratory morbidity in late-preterm and term neonates with meconium aspiration syndrome, pneumonia/sepsis, and perhaps pulmonary hemorrhage; surfactant replacement may be beneficial for these infants. This statement summarizes indications, administration, formulations, and outcomes for surfactant-replacement therapy. The impact of antenatal steroids and continuous positive airway pressure on outcomes and surfactant use in preterm infants is reviewed. Because respiratory insufficiency may be a component of multiorgan dysfunction, preterm and term infants receiving surfactant-replacement therapy should be managed in facilities with technical and clinical expertise to administer surfactant and provide multisystem support.

Inhaled nitric oxide therapy during the transport of neonates with persistent pulmonary hypertension or severe hypoxic respiratory failure

Our aim was to determine whether starting inhaled nitric oxide (iNO) on critically ill neonates with severe hypoxemic respiratory failure and/or persistent pulmonary hypertension (PPH), at a referring hospital at the start of transport, decreases the need for extracorporeal membrane oxygenation (ECMO), lessens the number of hospital days and improves survival in comparison with those patients who were started on iNO only at the receiving facility. The study was a retrospective review of 94 charts of neonates that had iNO initiated by the transport team at a referring hospital or only at the tertiary neonatal intensive care unit (NICU) of the receiving hospital. Data collected included demographics, mode of transport, total number of hospital days, days on inhaled nitric oxide and ECMO use. Of the 94 patients, 88 were included. Of these, 60 were started on iNO at the referring facility (Field-iNO) and 28 were started at the receiving NICU (CHLA-iNO). All patients survived transport to the receiving NICU. Death rates and ECMO use were similar in both groups. Overall, patients who died were younger and had lower birth weights and Apgar scores. For all surviving patients who did not require ECMO, the length of total hospital stay (median days 22 versus 38, P = 0.018), and the length of the hospital stay at the receiving hospital (median days 18 versus 29, P = 0.006), were significantly shorter for the Field-iNO patients than for the CHLA-iNO patients, respectively. Earlier initiation of iNO may decrease length of hospital stay in surviving neonates with PPH not requiring ECMO.

How does the changing profile of infants who are referred for extracorporeal membrane oxygenation affect their overall respiratory outcome?

OBJECTIVE

Extracorporeal membrane oxygenation has been shown to be effective in term neonates with severe but reversible lung disease within the context of randomized, controlled trials. Extracorporeal membrane oxygenation now has been open to a wider population of infants in the United Kingdom, and other treatments have become available. The population referred for extracorporeal membrane oxygenation, therefore, has changed. The aims of this study were to (1) compare respiratory outcomes of infants who received extracorporeal membrane oxygenation in recent years with those from 10 years ago and (2) determine whether respiratory outcome varied with diagnostic group.

METHODS

All infants who were referred to a single extracorporeal membrane oxygenation center and were <12 months old during a 7-year period were eligible. One year after extracorporeal membrane oxygenation, lung volume, airway conductance, maximum expiratory flow, and indices of tidal breathing were measured.

RESULTS

A total of 106 infants (77% of those eligible) were tested, and results were compared with those of 51 infants referred for extracorporeal membrane oxygenation as part of the original United Kingdom extracorporeal membrane oxygenation trial. Lung volume was not different, but there was a strong trend for the infants who were seen in more recent years to have better forced expiratory flow and specific airway conductance. Restricting analysis to the major subgroup (meconium aspiration) confirmed these findings. When divided into diagnostic subgroups, infants who required extracorporeal membrane oxygenation for respiratory distress syndrome or who were >2 weeks old when extracorporeal membrane oxygenation was commenced had a poorer respiratory outcome than others.

CONCLUSIONS

The respiratory outcome of infants who were treated beyond the tightly regulated criteria of the United Kingdom trial remains good and even shows a trend toward improvement. Certain subgroups require extracorporeal membrane oxygenation for longer and have poorer pulmonary function when followed up.

ECMO for meconium aspiration syndrome: support for relaxed entry criteria

We compared the morbidity of patients with meconium aspiration syndrome (MAS) with that in patients with all other respiratory conditions treated with extracorporeal membrane oxygenation (ECMO) (no MAS). If ECMO for MAS was associated with a lower complication rate, then relaxed ECMO entry criteria could be considered. A retrospective review was performed of all patients in the national extracorporeal life support (ELSO) registry from 1989 to 2004. Complications were divided into mechanical, hematologic, neurologic, renal, pulmonary, cardiovascular, infectious, and metabolic categories. MAS and no-MAS patients were divided into veno-venous (VV) or veno-arterial (VA) ECMO categories, based on mode of ECMO used, and number of complications per patient in each category was determined. Statistical significance was determined by Chi-square test. A total of 1587 patients (700 MAS, 887 no MAS) on VV ECMO and 2723 (572 MAS, 2151 no MAS) on VA ECMO were identified with a total of 2415 complications in MAS and 9550 in no-MAS patients. Overall, MAS patients had a significantly lower number of complications per patient in each category versus no-MAS patients. These results indicate that regardless of type of ECMO, there are fewer complications on ECMO in MAS versus no-MAS patients. These data support the consideration of relaxed ECMO entry criteria for MAS.

Survie et devenir clinique des nouveau-nés mis en assistance respiratoire extracorporelle

OBJECTIVES

To assess the prognosis of newborn infants with refractory hypoxemia who required extracorporeal membrane oxygenation (ECMO).

METHODS

Eighty-nine newborn infants treated by ECMO during more than 24 hours over a 8-year period (1996-2003) were included in this observational cohort study with a 9-month and 24-month evaluation.

RESULTS

Respiratory failure mainly resulted from meconium aspiration syndrome (MAS, 43%), congenital diaphragmatic hernia (CDH, 15%) and sepsis (15%). Overall survival at hospital discharge was 67%. Infants with MAS had the best survival rate (82%) and those with CDH had the worst (46%). Of the remaining 60 survivors, 53% remained oxygen dependent at 28 days and 33% at 45 days. At the age of 2 years, only 1 infant remained oxygen dependent (but did not required oxygen at 3 years) and only 3 infants had significant neurodevelopmental problems. CDH group was associated with a prolonged duration in supplementary oxygen (P<0.001) and a prolonged duration for tube feeding (P=0.01) as compared with other diagnoses. Regarding neurologic outcome, CDH infants had the poorer neurological acquisition rate at 9 months but a very good evolution by the time of the 24-month evaluation.

CONCLUSIONS

Morbidity in ECMO survivors is low considering the severity of illness in the newborn period, mainly related to pulmonary and feeding dysfunctions during the first months, in particular for the CDH group. Outcome at the age of 2 years of CDH infants is most often favourable regarding growth and neurodevelopmental evolution.

Trends in use and outcome of newborn infants treated with high frequency ventilation in Australia and New Zealand, 1996-2003

AIM

To examine the use of high frequency ventilation (HFV) to treat newborn infants in Australia and New Zealand and the associated complications and outcomes.

METHODS

Data for all infants receiving HFV were collected from the 28 neonatal intensive care units contributing to the Australian and New Zealand Neonatal Network database between 1996 and 2003, inclusive. For comparison, the same data were gathered on all infants who received conventional mechanical ventilation (CMV) and nasal continuous positive airway pressure.

RESULTS

HFV was used to treat 3270 infants (10.1% of all ventilated infants) between 1996 and 2003; uptake doubled during this period from 5.9% to 12.6% of ventilated infants per year. HFV was most frequently applied in the context of extreme prematurity (29.9% of ventilated infants <26 weeks gestation). HFV is being increasingly used to treat complex diseases such as meconium aspiration syndrome and congenital diaphragmatic hernia (12.2% and 10.6% in 1996 to 25.2% and 48.4% in 2003, respectively, chi2 -test for trend, P<0.001). Infants receiving HFV spent longer on respiratory support than infants treated with CMV (median 21 days compared with 7 days, Mann-Whitney test P<0.001) and required a higher initial FiO2 (median 0.8 compared to 0.5, Mann-Whitney test, P<0.001). The use of HFV was associated with a higher mortality than CMV and nasal continuous positive airway pressure (39.7%, 10.1% and 0.4%, chi2 -test, P<0.001). The incidence of death and intraventricular haemorrhage decreased over time in the HFV group (chi2 -test for trend, P<0.001 and P=0.02 respectively).

CONCLUSION

HFV is an established mode of neonatal ventilation in Australia and New Zealand. HFV is being applied to infants at the greatest risk of serious adverse outcomes, most likely as a rescue therapy.

Persistent pulmonary hypertension of the newborn: pathogenesis, etiology, and management

Persistent pulmonary hypertension of the newborn (PPHN) is characterized by severe hypoxemia shortly after birth, absence of cyanotic congenital heart disease, marked pulmonary hypertension, and vasoreactivity with extrapulmonary right-to-left shunting of blood across the ductus arteriosus and/or foramen ovale. In utero, a number of factors determine the normally high vascular resistance in the fetal pulmonary circulation, which results in a higher pulmonary compared with systemic vascular pressure. However, abnormal conditions may arise antenatally, during, or soon after birth resulting in the failure of the pulmonary vascular resistance to normally decrease as the circulation evolves from a fetal to a postnatal state. This results in cyanosis due to right-to-left shunting of blood across normally existing cardiovascular channels (foramen ovale or ductus arteriosus) secondary to high pulmonary versus systemic pressure. The diagnosis is made by characteristic lability in oxygenation of the infant, echocardiographic evidence of increased pulmonary pressure, with demonstrable shunts across the ductus arteriosus or foramen ovale, and the absence of cyanotic heart disease lesions. Management of the disease includes treatment of underlying causes, sedation and analgesia, maintenance of adequate systemic blood pressure, and ventilator and pharmacologic measures to increase pulmonary vasodilatation, decrease pulmonary vascular resistance, increase blood and tissue oxygenation, and normalize blood pH. Inhaled nitric oxide has been one of the latest measures to successfully treat PPHN and significantly reduce the need for extracorporeal membrane oxygenation.

Milrinone improves oxygenation in neonates with severe persistent pulmonary hypertension of the newborn

BACKGROUND

Many neonates with severe persistent pulmonary hypertension of the newborn (PPHN) are nonresponders to inhaled nitric oxide (iNO). Milrinone is a promising adjunctive therapy because of its pulmonary vasodilator properties and cardiotropic effects.

DESIGN

Case series of neonates with severe PPHN (defined as oxygenation index [OI] >20, failure of iNO therapy, and echocardiographic confirmation of PPHN).

SETTING

Tertiary neonatal intensive care unit.

SUBJECTS

Full-term (> or =37 weeks) neonates with severe PPHN who received intravenous milrinone.

MEASUREMENTS

The primary end point was the effect of intravenous milrinone on OI and hemodynamic stability over a 72-hour study period. Secondary end points examined included duration of iNO and degree of cardiorespiratory support.

RESULTS

Nine neonates at a mean gestation of 39.25 +/- 2.76 weeks, birth weight of 3668 +/- 649.1 g, and baseline OI of 28.1 +/- 5.9 received milrinone treatment after a poor initial response to iNO treatment. Intravenous milrinone was commenced at a median age of 21 hours (range, 18-49 hours), and patients were treated for median of 70 hours (range, 23-136). Oxygenation index was significantly reduced after milrinone treatment, particularly in the immediate 24 hours of treatment (8.0 +/- 6.6, P < .001). There was a significant improvement in heart rate (179 +/- 15.2 vs 149.6 +/- 22.4, P < .001) over the same period. Infants who received milrinone did not develop systemic hypotension; in fact, there was a nonsignificant trend toward improved blood pressure.

CONCLUSIONS

Intravenous milrinone produces early improvements in oxygenation without compromising systemic blood pressure.

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.