Venovenous versus venoarterial extracorporeal life support for pediatric respiratory failure: are there differences in survival and acute complications?

Multimodal Neurologic Monitoring in Patients Undergoing Extracorporeal Membrane Oxygenation

Introduction Extracorporeal membrane oxygenation (ECMO) is associated with a high rate of neurologic complications. Multimodal neurologic monitoring (MNM) has the potential for early detection and intervention. We examined the safety and feasibility of noninvasive MNM during ECMO. We hypothesized that survivors and non-survivors would have meaningful differences in transcranial Doppler (TCD) sonography and electroencephalographic (EEG) characteristics, which we aimed to identify. We also investigated adverse neurologic events and attempted to identify differences in EEG and TCD characteristics among patients based on the type of ECMO and the occurrence of these events. Material and methods We performed an observational study on all patients undergoing ECMO at Baylor St. Luke's Medical Center's critical care unit in Houston, Texas, United States, from January 2017 to February 2019. All patients underwent a noninvasive MNM protocol. Results NM was completed in 75% of patients; all patients received at least one component of the monitoring protocol. No adverse events were noted, showing the feasibility and safety of the protocol. The 60.4% of patients who did not survive tended to be older, had lower ejection fractions, and had lower median right middle cerebral artery (MCA) pulsatility and resistivity indexes. Patients undergoing venoarterial (VA)-ECMO had lower median left and right MCA velocities and lower right Lindegaard ratios than patients who underwent venovenous-ECMO. In VA-ECMO patients, EEG less often showed sleep architecture, while other findings were similar between groups. Adverse neurologic events occurred in 24.7% of patients, all undergoing VA-ECMO. Acute ischemic stroke occurred in 22% of patients, intraparenchymal hemorrhage in 4.9%, hypoxic-ischemic encephalopathy in 3.7%, subarachnoid hemorrhage in 2.5%, and subdural hematoma in 1.2%. Conclusion Our results suggest that MNM is safe and feasible for patients undergoing ECMO. Certain EEG and TCD findings could aid in the early detection of neurologic deterioration. MNM may not just be used in monitoring patients undergoing ECMO but also in prognostication and aiding clinical decision-making.

Pediatric ECLS Neurologic Management and Outcomes

Neurologic complications associated with extracorporeal life support (ECLS), including seizures, ischemia/infarction, and intracranial hemorrhage significantly increase morbidity and mortality in pediatric and neonatal patients. Prompt recognition of adverse neurologic events may provide a window to intervene with neuroprotective measures. Many neuromonitoring modalities are available with varying benefits and limitations. Several pre-ECLS and ECLS-related factors have been associated with an increased risk for neurologic complications. These may be patient- or circuit-related and include modifiable and non-modifiable factors. ECLS survivors are at risk for long-term neurological sequelae affecting neurodevelopmental outcomes. Possible long-term outcomes range from normal development to severe impairment. Patients should undergo a neurological evaluation prior to discharge, and neurodevelopmental assessments should be included in each patient's structured, multidisciplinary follow-up. Safe pediatric and neonatal ECLS management requires a thorough understanding of neurological complications, neuromonitoring techniques and limitations, considerations to minimize risk, and an awareness of possible long-term ramifications. With a focus on ECLS for respiratory failure, this manuscript provides a review of these topics and summarizes best practice guidelines from international organizations and expert consensus.

Extracorporeal Membrane Oxygenation in Pediatric Burn Patients Without Inhalation Injury: A Unique Population?

Prolonged mechanical ventilation (MV) before the initiation of extracorporeal membrane oxygenation (ECMO) is associated with decreased survival. Pediatric burn patients without inhalational injury are a unique population as they may be intubated for longer durations due to frequent interventions such as dressing changes and burn excisions. This study utilized the Extracorporeal Life Support Organization registry and evaluated patients 0 to 18 years old placed on ECMO and with a burn injury from January 2010 to December 2020. Inhalation injury was excluded. Descriptive statistics and bivariate analyses were performed. Multivariable logistic regression was used to assess the association between mortality and precannulation MV duration before ECMO cannulation, and odds ratios and predicted probabilities of mortality were estimated. Our cohort of 47 patients had a median age of 2.7 years old. Mortality occurred in 48.9% of the cohort. The overall median number of days on ECMO was 6.3 days, with no difference between survivors and non-survivors (6.8 days vs 6.3 days; P = .67). Survivors were ventilated for 4.1 days and non-survivors for 4.8 days before cannulation (P = .25). Regression modeling demonstrated that with each additional day on MV before ECMO cannulation, the odds of mortality increases by 12% (P = .03). Our study suggests that, similar to pediatric patients without thermal injury, increasing precannulation MV duration is associated with an increasing risk of mortality in pediatric burn patients without inhalational injury. Though the pediatric burn population is unique, evaluation of burn patients with respiratory failure for ECMO should be similar to the general population.

Cannulation approach and mortality in neonatal ECMO

OBJECTIVE

Identify associations between cannulation approach and mortality in neonates who received ECMO support for respiratory failure.

STUDY DESIGN

A retrospective analysis of neonates receiving ECMO for respiratory indications at a single quaternary-referral NICU. Associations between cannulation approach and mortality were assessed after adjustment for Neo-RESCUERS score. Cox Proportional Hazards (CPH) model was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for each variable and outcome.

RESULTS

Among 244 neonates, overall survival was 88%, with 71% undergoing VV cannulation. After adjusting for Neo-RESCUERS score, VA cannulation was associated with higher mortality during ECMO when compared with VV cannulation (HR 4.189, 95% CI 1.480-11.851, P = 0.0069). Disease-specific comparisons revealed no statistical difference in Neo-RESCUERS score between VA and VV cohorts; however, VA cannulation was associated with higher ECMO mortality for neonates with congenital diaphragmatic hernia (50% vs. 5.5%, Χ2 = 8.5965, P = 0.0034) and PPHN (20% vs. 1.8%, Χ2 = 9.1047, P = 0.0025) when compared with VV cannulation.

CONCLUSION

VA cannulation was associated with increased mortality in neonates while on ECMO for respiratory failure, which was independent of illness severity.

Venovenous Versus Venoarterial Extracorporeal Membranous Oxygenation in Inotrope Dependent Pediatric Patients With Respiratory Failure

Patients with respiratory failure requiring inotropes or vasopressors are often placed on venoarterial (VA) extracorporeal membrane oxygenation (ECMO), as venovenous (VV) ECMO does not provide direct circulatory support. This retrospective multicenter study compared outcomes for 103 pediatric patients, with hemodynamic compromise, placed on VV ECMO for respiratory failure to those placed on VA ECMO. The primary outcome was survival to hospital discharge. Fifty-seven (55%) study participants were supported on VV ECMO. The two groups had similar PRISM III scores at pediatric intensive care unit (PICU) admission, and vasoactive-inotropic scores at ECMO cannulation. More VV ECMO patients received inhaled nitric oxide (iNO) (54.4 vs. 34.8%; p = 0.04) and had a higher oxygenation index (median 41.5 vs. 19.5; p = 0.04) pre-ECMO. More VA ECMO patients had cardiac dysfunction and cardiac arrest pre-ECMO (50 vs. 14%; p < 0.0001). In univariable analysis, survival to hospital discharge was higher in the VV vs. VA ECMO group (72 vs. 44%; p = 0.005), however, in multivariable models, cannulation type was confounded by cardiopulmonary resuscitation and was not independently associated with survival. VV survivors had longer ECMO duration compared with VA survivors (median, 7 vs. 4.5 days; p = 0.036) but similar PICU and hospital days. No significant difference was noted in functional outcomes or comorbidities at discharge. Cannulation type is not independently associated with survival to hospital discharge in pediatric patients on vasoactive infusions at the time of ECMO cannulation for respiratory indications.

Extracorporeal Membrane Oxygenation Support for Pediatric Burn Patients: Is It Worth the Risk?

OBJECTIVES

Examine the outcomes of pediatric burn patients requiring extracorporeal membrane oxygenation to determine whether extracorporeal membrane oxygenation should be considered in this special population.

DESIGN

Retrospective cohort study.

SETTING

All extracorporeal membrane oxygenation centers reporting to the Extracorporeal Life Support Organization.

SUBJECTS

Pediatric patients (birth to younger than 18 yr) who were supported with extracorporeal membrane oxygenation with a burn diagnosis between 1990 and 2016.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 113 patients were identified from the registry by inclusion criteria. Patients cannulated for respiratory failure had the highest survival (55.7%, n = 97) compared to those supported for cardiac failure (33.3%, n = 6) or extracorporeal cardiopulmonary resuscitation (30%, n = 10). Patients supported on venovenous extracorporeal membrane oxygenation for respiratory failure had the best overall survival at 62.2% (n = 37). Important for the burn population, rates of surgical site bleeding were similar to other surgical patients placed on extracorporeal membrane oxygenation at 22.1%. Cardiac arrest prior to cannulation was associated with increased hospital mortality (odds ratio, 3.41; 95% CI, 0.16-1.01; p = 0.048). Following cannulation, complications including the need for inotropes (odds ratio, 2.64; 95% CI, 1.24-5.65; p = 0.011), presence of gastrointestinal hemorrhage (p = 0.049), and hyperglycemia (glucose > 240 mg/dL) (odds ratio, 3.42; 95% CI, 1.13-10.38; p = 0.024) were associated with increased mortality. Of patients with documented burn percentage of total body surface area (n = 19), survival was 70% when less than 60% total body surface area was involved.

CONCLUSIONS

Extracorporeal membrane oxygenation could be considered as an additional level of support for the pediatric burn population, especially in the setting of respiratory failure. Additional studies are necessary to determine the optimal timing of cannulation and other patient characteristics that may impact outcomes.

Venovenous Extracorporeal Membrane Oxygenation for Patients With Return of Spontaneous Circulation After Cardiac Arrest Owing to Acute Respiratory Distress Syndrome

OBJECTIVE

The primary objective of this study was to determine the survival to hospital discharge of patients who were treated with venovenous (VV) extracorporeal membrane oxygenation (ECMO) for respiratory failure after cardiac arrest.

DESIGN

Retrospective chart review.

SETTING

University-affiliated tertiary care hospitals.

PARTICIPANTS

The study comprised 21 patients.

INTERVENTIONS

Implementation of VV ECMO in patients with return of spontaneous circulation after cardiac arrest owing to respiratory insufficiency.

MEASUREMENTS AND MAIN RESULTS

The most common etiology of arrest was pneumonia-associated acute respiratory distress syndrome (8/21 [38%]). Overall, 12/21(57%) patients survived to hospital discharge. Two of 12 (17%) patients required hemodialysis upon discharge.

CONCLUSION

VV ECMO may be an appropriate alternative to venoarterial ECMO in select patients with return of spontaneous circulation after cardiac arrest owing to profound respiratory failure.

Extracorporeal Life Support Organization Registry International Report 2016

Data on extracorporeal life support (ECLS) use and survival submitted to the Extracorporeal Life Support Organization's data registry from the inception of the registry in 1989 through July 1, 2016, are summarized in this report. The registry contained information on 78,397 ECLS patients with 58% survival to hospital discharge. Extracorporeal life support use and centers providing ECLS have increased worldwide. Extracorporeal life support use in the support of adults with respiratory and cardiac failure represented the largest growth in the recent time period. Extracorporeal life support indications are expanding, and it is increasingly being used to support cardiopulmonary resuscitation in children and adults. Adverse events during the course of ECLS are common and underscore the need for skilled ECLS management and appropriately trained ECLS personnel and teams.

Extracorporeal Membrane Oxygenation for Neonates with Congenital Renal and Urological Anomalies and Pulmonary Hypoplasia: A Case Report and Review of the Extracorporeal Life Support Organization Registry

Objective  Congenital anomalies of the kidney and urinary tract constitute up to 30% of anomalies identified in the neonatal period. In utero oligohydramnios is often associated with pulmonary hypoplasia and respiratory failure in the neonate who may not be responsive to mechanical ventilation. Placement of these neonates on extracorporeal membrane oxygenation (ECMO) remains controversial and is considered in most centers to be a relative contraindication. The objective of this study is to use the Extracorporeal Life Support Organization (ELSO) database to describe the outcomes and complications of patients with congenital renal and urogenital anomalies with pulmonary hypoplasia who underwent ECMO in the neonatal period. Data Sources  Data from the ELSO registry were retrospectively reviewed for all patients with congenital renal and urogenital anomalies with pulmonary hypoplasia treated with ECMO support between 1990 and November 2014 using ICD-9 diagnosis codes. Data Synthesis  We identified 45 patients. The average age of the patient at the time of ECMO was 1.7 days (range: 0-14 days) and weight was 3.1 kg (interquartile range [IQR]: 2.5-3.3). Patients spent an average of 162 hours on ECMO (IQR: 81-207). The majority of patients were managed with venoarterial ECMO (60%), and the overall survival of this cohort was 42%. Survivors had higher weights (3.4 vs. 2.8 kg; p  < 0.019) and were more likely to be male (90 vs. 44%; p  < 0.002). Patients with obstructive urogenital lesions had an overall survival of 71 versus 16.6% in patients with a primary intrinsic renal diagnosis ( p  = 0.004). Renal replacement therapy was required in 51% of the patients during their ECMO support. Conclusion  Neonates with renal or urogenital disease and pulmonary hypoplasia have an overall survival rate of 42%. Patients with a diagnosis of urogenital obstruction have much more favorable outcomes when compared with those with intrinsic renal disease such as polycystic kidney disease.

Extracorporeal respiratory support in adult patients

In patients with severe respiratory failure, either hypoxemic or hypercapnic, life support with mechanical ventilation alone can be insufficient to meet their needs, especially if one tries to avoid ventilator settings that can cause injury to the lungs. In those patients, extracorporeal membrane oxygenation (ECMO), which is also very effective in removing carbon dioxide from the blood, can provide life support, allowing the application of protective lung ventilation. In this review article, we aim to explore some of the most relevant aspects of using ECMO for respiratory support. We discuss the history of respiratory support using ECMO in adults, as well as the clinical evidence; costs; indications; installation of the equipment; ventilator settings; daily care of the patient and the system; common troubleshooting; weaning; and discontinuation.

The Incidence of Acute Kidney Injury and Its Effect on Neonatal and Pediatric Extracorporeal Membrane Oxygenation Outcomes: A Multicenter Report From the Kidney Intervention During Extracorporeal Membrane Oxygenation Study Group

OBJECTIVE

In a population of neonatal and pediatric patients on extracorporeal membrane oxygenation; to describe the prevalence and timing of acute kidney injury utilizing a consensus acute kidney injury definition and investigate the association of acute kidney injury with outcomes (length of extracorporeal membrane oxygenation and mortality).

DESIGN

Multicenter retrospective observational cohort study.

SETTING

Six pediatric extracorporeal membrane oxygenation centers.

PATIENTS

Pediatric patients (age, < 18 yr) on extracorporeal membrane oxygenation at six centers during a period of January 1, 2007, to December 31, 2011.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Complete data were analyzed for 832 patients on extracorporeal membrane oxygenation. Sixty percent of patients had acute kidney injury utilizing the serum creatinine Kidney Disease Improving Global Outcomes criteria (AKI) and 74% had acute kidney injury using the full Kidney Disease Improving Global Outcomes criteria including renal support therapy (AKI). Of those who developed acute kidney injury, it was present at extracorporeal membrane oxygenation initiation in a majority of cases (52% AKI and 65% AKI) and present by 48 hours of extracorporeal membrane oxygenation support in 86% (AKI) and 93% (AKI). When adjusted for patient age, center of support, mode of support, patient complications and preextracorporeal membrane oxygenation pH, the presence of acute kidney injury by either criteria was associated with a significantly longer duration of extracorporeal membrane oxygenation support (AKI, 152 vs 110 hr; AKI, 153 vs 99 hr) and increased adjusted odds of mortality at hospital discharge (AKI: odds ratio, 1.77; 1.22-2.55 and AKI: odds ratio, 2.50; 1.61-3.90). With the addition of renal support therapy to the model, acute kidney injury was associated with a longer duration of extracorporeal membrane oxygenation support (AKI, 149 vs 121 hr) and increased risk of mortality at hospital discharge (AKI: odds ratio, 1.52; 1.04-2.21).

CONCLUSION

Acute kidney injury is present in 60-74% of neonatal-pediatric patients supported on extracorporeal membrane oxygenation and is present by 48 hours of extracorporeal membrane oxygenation support in 86-93% of cases. Acute kidney injury has a significant association with increased duration of extracorporeal membrane oxygenation support and increased adjusted odds of mortality at hospital discharge.

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.

Venovenous Extracorporeal Life Support in Single-Ventricle Patients with Acute Respiratory Distress Syndrome

There is new and growing experience with venovenous extracorporeal life support (VV ECLS) for neonatal and pediatric patients with single-ventricle physiology and acute respiratory distress syndrome (ARDS). Outcomes in this population have been defined but could be improved; survival rates in single-ventricle patients on VV ECLS for respiratory failure are slightly higher than those in single-ventricle patients on venoarterial ECLS for cardiac failure (48 vs. 32-43%), but are lower than in patients with biventricular anatomy (58-74%). To that end, special consideration is necessary for patients with single-ventricle physiology who require VV ECLS for ARDS. Specifically, ARDS disrupts the balance between pulmonary and systemic blood flow through dynamic alterations in cardiopulmonary mechanics. This complexity impacts how to run the VV ECLS circuit and the transition back to conventional support. Furthermore, these patients have a complicated coagulation profile. Both venous and arterial thrombi carry marked risk in single-ventricle patients due to the vulnerability of the pulmonary, coronary, and cerebral circulations. Finally, single-ventricle palliation requires the preservation of low resistance across the pulmonary circulation, unobstructed venous return, and optimal cardiac performance including valve function. As such, the proper timing as well as the particular conduct of ECLS might differ between this population and patients without single-ventricle physiology. The goal of this review is to summarize the current state of knowledge of VV ECLS in the single-ventricle population in the context of these special considerations.

Neurologic Complications of Extracorporeal Membrane Oxygenation

Background and Purpose

The rate and outcomes of neurologic complications of patients receiving extracorporeal membrane oxygenation (ECMO) are poorly understood. The purpose of this study was to identify these parameters in ECMO patients.

Methods

All patients receiving ECMO were selected from the Nationwide Inpatient Sample between 2001-2011. The rate and outcomes of neurologic complications [acute ischemic stroke, intracranial hemorrhage (ICH), and seizures] among these patients was determined. Discharge status, mortality, length of stay, and hospitalization costs were compared between patients with and without neurologic complications using chi-squared tests for categorical variables and Student's t-test for continuous variables.

Results

In total, 23,951 patients were included in this study, of which 2,604 (10.9%) suffered neurologic complications of seizure (4.1%), stroke (4.1%), or ICH (3.6%). When compared to patients without neurologic complications, acute ischemic stroke patients had significantly higher rates of discharge to a long-term facility (12.2% vs. 6.8%, p<0.0001) and a significantly longer mean length of stay (41.6 days vs. 31.9 days, p<0.0001). ICH patients had significantly higher rates of discharge to a long-term facility (9.5% vs. 6.8%, p=0.007), significantly higher mortality rates (59.7% vs. 50.0%, p<0.0001), and a significantly longer mean length of stay (41.8 days vs. 31.9 days) compared to patients without neurologic complications. These outcomes did not differ significantly between seizure patients and patients without neurologic complications.

Conclusions

Given the increasing utilization of ECMO and the high costs and poor outcomes associated with neurologic complications, more research is needed to help determine the best way to prevent these sequelae in this patient population.

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.

Acute kidney injury in children: an update on diagnosis and treatment

The concept and definition of acute kidney injury (AKI) in adults and children has undergone significant change in recent years. Biomarker assessment is aiding in description, defining and understanding timing of AKI. AKI demonstrates unique characteristics in association with sepsis and septic shock, organ dysfunction, and fluid overload. Treatment remains problematic, but growing experience with pediatric continuous renal replacement therapies has improved the delivery of care in children. Increasingly, continuous renal replacement therapy is provided in combination with other extracorporeal technologies, and approaches are advancing to improve combined therapy use.

Management of blunt tracheobronchial trauma in the pediatric age group

INTRODUCTION

Tracheobronchial rupture (TBR) due to blunt chest trauma is a rare but life-threatening injury in the pediatric age group. The aim of this study was to propose a treatment strategy including bronchoscopy, surgery and extracorporeal membrane oxygenation (ECMO) to optimize the emergency management of these patients.

METHODS

We reviewed a series of 27 patients with post-traumatic TBR treated since 1996 in our pediatric trauma center.

RESULTS

Seven cases had persistent and large volume air leaks. Flexible bronchoscopy was performed in cases of persistent or large volume air leaks. It permitted accurate visualization of the rupture and its extent. It allowed for a clear-cut positioning of the endotracheal tube. Five were managed operatively. Four cases were considered to be life-threatening because of the combination of severe respiratory distress with hemodynamic instability. One of them had severe tracheal laceration and died. Another one had bilateral bronchi disconnection. Based on clinical and endoscopic findings, surgical repair was performed using extracorporeal membrane oxygenation as a ventilatory support. It provided quick relief from the injury, which was previously expected to result in a fatal issue.

CONCLUSIONS

Prompt diagnosis and accurate management of surviving patients admitted to emergency rooms are necessary. Bronchoscopy remains a critical diagnosis step. Surgery is warranted for large tracheobronchial tears and ECMO could be beneficial as supportive therapy for selected cases.

Current knowledge of acute lung injury and acute respiratory distress syndrome

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) continues to be a major cause of mortality in adult and pediatric critical care medicine. This article discusses the pulmonary sequelae associated with ALI and ARDS, the support of ARDS with mechanical ventilation, available adjunctive therapies, and experimental therapies currently being tested. It is hoped that further understanding of the fundamental biology, improved identification of the patient's inflammatory state, and application of therapies directed at multiple sites of action may ultimately prove beneficial for patients suffering from ALI/ARDS.

A multicenter international survey of renal supportive therapy during ECMO: the Kidney Intervention During Extracorporeal Membrane Oxygenation (KIDMO) group

Acute kidney injury and fluid overload (FO) are associated with increased mortality in critically ill patients, including the subset supported with extracorporeal membrane oxygenation (ECMO). The indication for and method of application of renal support therapy (RST) during ECMO is largely unknown beyond single-center experiences. The current study uses a survey design to document practice variation regarding RST, including indication, method of interface with the ECMO circuit, and prescribing practices. Sixty-five international ECMO centers (31%) responded to an online electronic survey regarding RST during ECMO. Nearly a quarter of centers (23%) reported using no RST during ECMO. Among those using the therapy, the predominant mode of therapy applied was convection and included slow continuous ultrafiltration and continuous venovenous hemofiltration. The predominant indication for RST was the treatment (43%) or prevention (16%) of FO. Nephrology rather than critical care medicine is reported as the prescribing service in a majority of centers with a significant difference between US centers and non-US centers. The results of this study identify a wide variation in practice regarding RST during ECMO that will offer multiple important avenues for further research by this group and others regarding the interface of RST and ECMO.

The endocrinological responses of veno-venous extracorporeal membrane oxygenation on hypoxic fetal lambs

OBJECTIVE

The purpose of this study was to observe endocrinological responses of veno-arterial and veno-venous extracorporeal membrane oxygenation (V-A and V-V ECMO) to support fetal oxygenation in utero.

METHODS

An ECMO system with a centrifugal pump was applied to six chronically instrumented fetal lambs, at 126-134 days of gestation. Blood was obtained through a double-lumen catheter inserted into the right atrium. After oxygenation, the blood was returned through a single-lumen catheter into either the carotid artery (veno-arterial; V-A ECMO) or the right atrium (V-V ECMO). After fetal hypoxia had been experimentally produced, V-A ECMO or V-V ECMO was instituted to maintain fetal oxygenation. We compared fetal blood gases and concentrations of atrial natriuretic peptide (ANP), epinephrine and norepinephrine with both routes of ECMO.

RESULTS

Fetal carotid artery pH did not change during hypoxemia, but decreased after instituting V-A ECMO and V-V ECMO. After instituting V-A ECMO or V-V ECMO for 30 min, oxygen partial pressure (pO2) in the fetal cranial carotid artery recovered from the hypoxic level. The ANP concentration in V-V ECMO was significantly lower than that in V-A ECMO. Fetal serum epinephrine and norepinephrine concentrations significantly increased in association with hypoxic stimulation. There was a further increase in fetal serum epinephrine concentration after instituting V-A ECMO. No significant difference in concentration was found after instituting V-V ECMO from that of after the institution of V-A ECMO.

CONCLUSIONS

This study suggested that V-V ECMO may possibly be less invasive than V-A ECMO for fetal heart, because ANP, a cardiac distress index, was lower in V-V ECMO than in V-A ECMO.

20-year experience of prolonged extracorporeal membrane oxygenation in critically ill children with cardiac or pulmonary failure

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a rescue therapy for life-threatening respiratory or circulatory failure. Although outcomes are favorable with short-term ECMO therapy, data on the outcomes of prolonged ECMO therapy in children are very limited. This study aimed to study morbidity and mortality associated with prolonged ECMO therapy (≥28 days) in children with refractory cardiac or pulmonary failure.

METHODS

We conducted a retrospective review of all children≤18 years supported with ECMO for ≥28 days between January 1991 and September 2011 at the Arkansas Children's Hospital. The data collected in our study included patient demographic information; diagnosis; indication for ECMO; ECMO support details; medical and surgical history; laboratory, microbiologic, and radiographic data; information on organ dysfunction; complications; and patient outcomes. The outcome variables evaluated in this report included survival to ECMO decannulation, survival to hospital discharge, and current survival with emphasis on neurologic, renal, pulmonary, and other end organ function.

RESULTS

During the study period, 984 events in 951 patients were supported with ECMO with a 30-day survival of 666 events (68%). Only 22 ECMO runs were ≥28 days and were eligible for inclusion in this report. The longest ECMO run in our series was 1,206 hours (50 days). The average length of ECMO run in this cohort was 855±133 hours, with a mean intensive care unit length of stay of 56±27 days. Ten patients (45%) were successfully decannulated from ECMO. Six patients (27%) were alive 30 days after decannulation, and only 4 patients (19%) survived to hospital discharge. Of the 4 survivors, only 3 patients (14%) are living to date. Of the 3 living children, 2 have significant neurologic issues with brain atrophy and developmental delay, and 1 is awaiting renal transplant; all 3 survivors have chronic lung disease.

CONCLUSIONS

This case series highlights that the prolonged use of ECMO in children with refractory cardiac failure, respiratory failure, or both is associated with low survival. Furthermore, it suggests that the survivors of prolonged ECMO runs have significant long-term sequelae.

Extracorporeal membrane oxygenation cannulation trends for pediatric respiratory failure and central nervous system injury

BACKGROUND

Guidelines regarding arterial cannula site and cannula site-specific risks of central nervous system (CNS) injury for pediatric patients requiring extracorporeal membrane oxygenation (ECMO) support are lacking. We reviewed cannulation trends for pediatric respiratory failure and evaluated CNS complication rates by cannulation site and mode of support.

METHODS

The Extracorporeal Life Support Organization (ELSO) registry was queried for all pediatric respiratory failure patients <18 years treated from 1993-2007. The primary outcome was radiographic evidence of CNS injury.

RESULTS

Venoarterial (VA) support was used in 62% of 2617 ECMO runs. The carotid artery was used in 93% of VA patients. Femoral artery use increased in patients >5 years of age and >20 kg. Venovenous (VV) ECMO was used in >50% of children >10 years. No significant difference was identified in CNS injury between carotid and femoral cannulation in any age group but the femoral group was small (4.4%). VA support was independently associated with increased odds of CNS injury compared to VV cannulation (OR, 1.6).

CONCLUSION

VA ECMO is the most common mode of support in pediatric respiratory failure patients. Although no significant difference in CNS injury was noted between carotid and femoral artery cannulation, the odds of injury were significantly higher than VV support.

Extracorporeal membrane oxygenation for pediatric respiratory failure: Survival and predictors of mortality

OBJECTIVE

The last multicentered analysis of extracorporeal membrane oxygenation in pediatric acute respiratory failure was completed in 1993. We reviewed recent international data to evaluate survival and predictors of mortality.

DESIGN

Retrospective case series review.

SETTING

The Extracorporeal Life Support Organization Registry, which includes data voluntarily submitted from over 115 centers worldwide, was queried. The work was completed at the Division of Pediatric Critical Care, Department of Pediatrics, Primary Children's Medical Center, University of Utah, Salt Lake City, UT.

SUBJECTS

Patients aged 1 month to 18 yrs supported with extracorporeal membrane oxygenation for acute respiratory failure from 1993 to 2007.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 3,213 children studied. Overall survival remained relatively unchanged over time at 57%. Considerable variability in survival was found based on pulmonary diagnosis, ranging from 83% for status asthmaticus to 39% for pertussis. Comorbidities significantly decreased survival to 33% for those with renal failure (n = 329), 16% with liver failure (n = 51), and 5% with hematopoietic stem cell transplantation (n = 22). The proportion of patients with comorbidities increased from 19% during 1993 to 47% in 2007. Clinical factors associated with mortality included precannulation ventilatory support longer than 2 wks and lower precannulation blood pH.

CONCLUSIONS

Although the survival of pediatric patients with acute respiratory failure treated with extracorporeal membrane oxygenation has not changed, this treatment is currently offered to increasingly medically complex patients. Mechanical ventilation in excess of 2 wks before the initiation of extracorporeal membrane oxygenation is associated with decreased survival.

The evolution of patient selection criteria and indications for extracorporeal life support in pediatric cardiopulmonary failure: next time, let's not eat the bones

Bill James, baseball statistician and author, tells the story of hungry cavemen sitting about a campfire, waiting for tomatoes to ripen. One has the inspiration to throw an ox on the fire, and the first barbecue ensued and was endured. After eating, the conversation goes something like this. "There were some good parts." "Yeah, but there were some bad parts." And the smart one says, "This time, let's not eat the bones." The evolution of patient selection criteria for the use of extracorporeal support (ECLS) is a bit like those cavemen and their first barbecued ox. Extracorporeal life support technology and application to patient care is the unique result of a long standing history of ambitious attempt, evaluation, debate, collaboration and extension.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Extracorporeal membrane oxygenation as a lifesaving modality in the treatment of pediatric patients with burns and respiratory failure

PURPOSE

Several case series have described successful utilization of extracorporeal membrane oxygenation (ECMO) for the treatment of pediatric burn patients with respiratory failure. This study examines the Extracorporeal Life Support Organization registry experience in the treatment of these patients.

METHODS

The Extracorporeal Life Support Organization registry was queried from 1999 to 2008 for all patients not older than 18 years who suffered a burn-related injury.

RESULTS

Thirty-six patients met inclusion criteria. The mean age was 4.45 years, with an average weight of 20.9 kg. Survivors vs nonsurvivors had a shorter average time to ECMO (97 vs 126 hours, P = .890) and shorter average ECMO run times (193 vs 210 hours, P = .745). Seventeen patients underwent venovenous ECMO and 19 patients underwent venoarterial ECMO, with survival of 59% (n = 10) and 47% (n = 9), respectively (P = .493; odds ratio, 1.587; 95% confidence interval, 0.424-5.945). Overall survival was 53% (n = 19). Complications occurred in 28 patients (33 mechanical, 101 medical). The venoarterial group had 21 mechanical (n = 8) and 61 medical complications (n = 17), compared with the venovenous group with 12 mechanical (n = 8) and 40 medical complications (n = 11).

CONCLUSIONS

Extracorporeal membrane oxygenation can be a lifesaving modality for pediatric burn patients with respiratory failure. Survival is comparable to the reported survival of non-burn-related pulmonary failure pediatric patients requiring ECMO.

Extracorporeal membrane oxygenation for respiratory failure: comparison of venovenous versus venoarterial bypass

PURPOSE

This study compared the respiratory status before and during extracorporeal membrane oxygenation (ECMO) in patients receiving venovenous (VV) and venoarterial (VA) ECMO to evaluate the choice of ECMO in patients with respiratory failure.

METHOD

Between January 2003 and December 2007, 16 patients with respiratory failure required ECMO. Venovenous bypass and VA bypass were used in 9 cases (VV group) and 7 cases (VA group), respectively. The respiratory status before and during ECMO was compared between the two groups.

RESULTS

The percentage of patients requiring renal replacement therapy prior to ECMO use was significantly higher in the VA group than in the VV group. There were no significant differences between the two groups in PaO(2)/FIO(2), AaDO(2), pulmonary compliance, and the lung injury score prior to ECMO use. These parameters gradually improved in both groups; however, no significant intergroup differences were seen for up to 96 h after ECMO introduction. There was also no significant difference between the two groups in ECMO removal rate (VV group: 56%, VA group: 43%).

CONCLUSION

These results suggest that VV ECMO is comparable to VA ECMO, and can maintain sufficient respiratory support when VV ECMO is introduced to respiratory failure patients lacking evidence of renal and/or heart failure.

Extracorporeal membrane oxygenation for the support of infants, children, and young adults with acute myocarditis: a review of the Extracorporeal Life Support Organization registry

OBJECTIVE

To describe survival outcomes for pediatric patients supported with extracorporeal membrane oxygenation for severe myocarditis and identify risk factors for in-hospital mortality.

DESIGN

Retrospective review of Extracorporeal Life Support Organization registry database.

SETTING

Data reported to Extracorporeal Life Support Organization from 116 extracorporeal membrane oxygenation centers.

PATIENTS

Patients < or = 18 yrs of age supported with extracorporeal membrane oxygenation for myocarditis during 1995 to 2006.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 19,348 reported pediatric extracorporeal membrane oxygenation uses from 1995 to 2006, 260 runs were for 255 patients with a diagnosis of myocarditis (1.3%). Survival to hospital discharge was 61%. Seven patients (3%) underwent heart transplantation and six patients survived to discharge. Of 100 patients not surviving to hospital discharge, extracorporeal membrane oxygenation support was withdrawn in 70 (70%) with multiple organ failure as the indication in 58 (83%) patients. In a multivariable model, female gender (adjusted odds ratio, 2.3, 95% confidence interval, 1.3-4.2), arrhythmia on extracorporeal membrane oxygenation (adjusted odds ratio, 2.7, 95% confidence interval, 1.5-5.1), and renal failure requiring dialysis (adjusted odds ratio, 5.1, 95% confidence interval, 2.3-11.4) were associated with increased odds of in-hospital mortality.

CONCLUSION

Extracorporeal membrane oxygenation is a valuable tool to rescue children with severe cardiorespiratory compromise related to myocarditis. Female gender, arrhythmia on extracorporeal membrane oxygenation, and need for dialysis during extracorporeal membrane oxygenation were associated with increased mortality.

Plasma concentrations of inflammatory cytokines rise rapidly during ECMO-related SIRS due to the release of preformed stores in the intestine

Extracorporeal membrane oxygenation (ECMO) is a life-saving support system used in neonates and young children with severe cardiorespiratory failure. Although ECMO has reduced mortality in these critically ill patients, almost all patients treated with ECMO develop a systemic inflammatory response syndrome (SIRS) characterized by a 'cytokine storm', leukocyte activation, and multisystem organ dysfunction. We used a neonatal porcine model of ECMO to investigate whether rising plasma concentrations of inflammatory cytokines during ECMO reflect de novo synthesis of these mediators in inflamed tissues, and therefore, can be used to assess the severity of ECMO-related SIRS. Previously healthy piglets (3-week-old) were subjected to venoarterial ECMO for up to 8 h. SIRS was assessed by histopathological analysis, measurement of neutrophil activation (flow cytometry), plasma cytokine concentrations (enzyme immunoassays), and tissue expression of inflammatory genes (PCR/western blots). Mast cell degranulation was investigated by measurement of plasma tryptase activity. Porcine neonatal ECMO was associated with systemic inflammatory changes similar to those seen in human neonates. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) concentrations rose rapidly during the first 2 h of ECMO, faster than the tissue expression of these cytokines. ECMO was associated with increased plasma mast cell tryptase activity, indicating that increased plasma concentrations of inflammatory cytokines during ECMO may result from mast cell degranulation and associated release of preformed cytokines stored in mast cells. TNF-alpha and IL-8 concentrations rose faster in plasma than in the peripheral tissues during ECMO, indicating that rising plasma levels of these cytokines immediately after the initiation of ECMO may not reflect increasing tissue synthesis of these cytokines. Mobilization of preformed cellular stores of inflammatory cytokines such as in mucosal mast cells may have an important pathophysiological role in ECMO-related SIRS.

[ECMO: experience in paediatrics]

INTRODUCTION

ECMO (Extracorporeal Membrane Oxygenation) provides a vital support to patients with supposed reversible respiratory and/or cardiac failure, in whom conventional support techniques have been previously unsuccessful.

OBJECTIVES

To determinate the criteria used in our hospital to put paediatric patients on ECMO, compare their clinical course depending on their pathology (respiratory failure, congenital heart disease or sepsis) and identify the sequelae attributable to this technique.

MATERIAL AND METHOD

A retrospective review of clinical records of all patients on ECMO support in our centre, excluding those presenting typically in neonatal period.

RESULTS

ECMO was used on 16 patients from June 2001 to January 2007, of which 50% were males. The median age was 7 months (from 21 days to 11 years). The reason for starting ECMO was respiratory failure in 11 cases (oxygenation index >40 and/or alveolar-arterial oxygen gradient >605), congenital heart disease in 2 and sepsis in 3 (due to shock unresponsive to adequate resuscitation). The median time to starting ECMO from PICU admission was 3.58 days (from 12h to 9 days). Venovenous cannulation was used initially in 8 patients, but 5 of them needed venoarterial ECMO later. The technique was used for a mean of 8 days (from 1 to 28 days). The main complication was the isolation of bacteria in different cultures (8 patients). The overall survival was 50% (6 patients with respiratory failure and both patients submitted to cardiac surgery). Extracorporeal support was withdrawn in 7 children because their clinical situation was irreversible. Another patient died seven days after successful decannulation. We have not found any serious sequel among survivors that could be attributable to this technique.

CONCLUSIONS

Survival among children supported with ECMO in our hospital is similar to that recorded by the ELSO in 2004, although the prognosis depends on the initial pathology. There are different criteria for starting this technique depending on the underlying diseases: respiratory index of poor prognosis in patients with respiratory failure, haemodynamic instability in those with sepsis or cardiac failure after cardiovascular surgery. We have not found any serious sequel among the survivors which could be attributable to this technique.

Extracorporeal life support for severe respiratory failure in children with immune compromised conditions

OBJECTIVES

To examine a large cohort of children treated with extracorporeal life support (ECLS) for severe respiratory failure to investigate the hypothesis that patients with an immune compromise condition (ICC) would have reduced survival to hospital discharge compared with patients without this classification.

DESIGN

Retrospective cohort study.

SETTING

Extracorporeal Life Support Organization (ELSO) data registry.

PATIENTS

All nonneonatal pediatric patients receiving ECLS for respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

As of February 4, 2004, the ELSO registry contained 2,879 pediatric patients between 1 month and 19 yrs of age who were treated with ECLS for respiratory failure. Overall, 183 patients had at least one International Classification of Diseases (Ninth Revision) or Current Procedural Terminology code associated with an ICC; ICC status was associated with lower hospital survival (31 vs. 57 %; p < .001). Six ICC subgroups were also examined: immune deficiency, leukemia-lymphoma, cancer, opportunistic infection, solid organ transplant, and bone marrow transplant. Each ICC subgroup was also associated with reduced hospital survival, varying from a high of 34.6% (solid organ transplants) to a low of 0% (bone marrow transplant). In a multivariate logistic regression model that controlled for factors reported to be associated with survival and other respiratory interventions (high-frequency ventilation, inhaled nitric oxide, and surfactant), the presence of an ICC remained associated with reduced hospital survival (odds ratio 0.20-0.45; p < .001). In this multivariate model, an unexpected strong association between inhaled nitric oxide therapy and lower ECLS survival was observed (odds ratio 0.49-0.80; p < .001).

CONCLUSIONS

In this cohort of pediatric patients receiving ECLS for respiratory failure, survival to hospital discharge was reduced for each ICC subgroup examined and was approximately one in three for the overall group. Further study of the association of lower survival rates for patients who received inhaled nitric oxide prior to ECLS is needed.

Extracorporeal membrane oxygenation to aid cardiopulmonary resuscitation in infants and children

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been used to support cardiorespiratory function during pediatric cardiopulmonary resuscitation (CPR). We report on outcomes and predictors of in-hospital mortality after ECMO used to support CPR (E-CPR).

METHODS AND RESULTS

Outcomes for patients aged <18 years using E-CPR were analyzed with data from the Extracorporeal Life Support Organization, and predictors of in-hospital mortality were determined. Of 26,242 ECMO uses reported, 695 (2.6%) were for E-CPR (n=682 patients). Survival to hospital discharge was 38%. In a multivariable model, pre-ECMO factors such as cardiac disease (odds ratio [OR] 0.51, 95% confidence interval [CI] 0.31 to 0.82) and neonatal respiratory disease (OR 0.28, 95% CI 0.12 to 0.66), white race (OR 0.65, 95% CI 0.45 to 0.94), and pre-ECMO arterial blood pH >7.17 (OR 0.50, 95% CI 0.30 to 0.84) were associated with decreased odds of mortality. During ECMO, renal dysfunction (OR 1.89, 95% CI 1.17 to 3.03), pulmonary hemorrhage (OR 2.23, 95% CI 1.11 to 4.50), neurological injury (OR 2.79, 95% CI 1.55 to 5.02), CPR during ECMO (OR 3.06, 95% CI 1.42 to 6.58), and arterial blood pH <7.2 (OR 2.23, 95% CI 1.23 to 4.06) were associated with increased odds of mortality.

CONCLUSIONS

ECMO used to support CPR rescued one third of patients in whom death was otherwise certain. Patient diagnosis, absence of severe metabolic acidosis before ECMO support, and uncomplicated ECMO course were associated with improved survival.

Continuous renal replacement therapy in neonates and young infants during extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a therapy that ensures adequate tissue oxygen delivery in patients suffering cardiac and/or respiratory failure that are unresponsive to conventional therapy. During ECMO, it is common to see a decrease in urine output that may be associated with acute renal failure. In this context, continuous renal replacement therapy (CRRT) should be considered. Our aim is to evaluate a pioneer experience in Latin America, related to the use of CRRT in a group of neonatal-pediatric patients during ECMO. We conducted a retrospective review of patients treated with ECMO at our institution between May 2003 and May 2005. Twelve infants were treated with ECMO, six of them also underwent CRRT. The main reasons for CRRT initiation were fluid overload and progressive azotemia. Observed complications were clots in the filter and excessive ultrafiltration. CRRT was successful in fluid management and solute clearance in all patients. Discharge survival rate was 83%, all of them with normal renal function. Concurrent CRRT with ECMO is technically feasible and efficacious in the management of fluid overload and solute clearance. We report the first experience with these therapies in a Latin American neonatal-pediatric ECMO program associated with the Extracorporeal Life Support Organization.

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.

Extracorporeal membrane oxygenation to rescue profound pulmonary hemorrhage due to idiopathic pulmonary hemosiderosis in a child

Idiopathic pulmonary hemosiderosis (IPH) is a rare cause of diffuse alveolar hemorrhage (DAH) in pediatric patients. During the acute phase, death due to massive alveolar hemorrhage and subsequent severe respiratory failure with associated multiple organ failure often occurs. We report the case of an 11-year-old girl who developed severe hypoxemic respiratory failure and pulmonary hemorrhage. Extracorporeal membrane oxygenation (ECMO) was instituted on the next day because medical treatment and mechanical ventilation failed to maintain oxygenation. She was successfully decannulated 5 days later without ECMO-related complications. Four months later, she was intubated again and the diagnosis of IPH was made by open lung biopsy. She was treated with systemic steroid therapy and discharged smoothly. We suggest that ECMO provides a chance of recovery and survival for patients with IPH, even if accompanied by severe pulmonary hemorrhage.

Central nervous system complications during pediatric extracorporeal life support: incidence and risk factors

OBJECTIVE

Identify the incidence and risk factors for development of acute, severe central nervous system (CNS) complications of pediatric extracorporeal life support (ECLS).

DESIGN

Retrospective review of Extracorporeal Life Support Organization (ELSO) registry database.

SETTING

Pediatric intensive care units of 115 tertiary centers internationally.

PATIENTS

Pediatric patients, 1 month to 18 yrs of age, who had ECLS between the years 1981-2002.

MEASUREMENTS AND MAIN RESULTS

Data concerning 4,942 patients who underwent one run of ECLS were analyzed. Six hundred thirty-six patients (12.9%) developed acute, severe CNS complications. Patients who required ECLS during extracorporeal cardiopulmonary resuscitation (n = 161; 3.3%) were more likely to develop CNS complications (n = 42; 26.1%) than patients who did not have extracorporeal cardiopulmonary resuscitation (p < .001; odds ratio [OR], 2.48; 95% confidence interval [CI], 1.73-3.57). Stepwise logistic regression analysis of therapies patients received before initiation of ECLS showed that the use of a left ventricular assist device (p = .001; OR, 3.45; 95% CI, 1.64-7.22), bicarbonate (p < .001; OR, 1.61; 95% CI, 1.26-2.05), and vasopressor/inotropic medications (p = .035; OR, 1.22; 95% CI, 1.01-1.48) were significant independent predictors of development of CNS complications. Among patients who had pulmonary failure as an indication for ECLS, the CNS complication rate was significantly higher for those treated with venoarterial ECLS than those who had venovenous ECLS (13.5% vs. 5.7%; p < .001; OR, 0.43; 95% CI, 0.34-0.67). Multiple logistic regression analysis of the complications other than CNS complications associated with the use of ECLS showed that pH <7.20, creatinine concentration >3.0 mg/dL, use of inotropes, presence of myocardial stun, and requirement of cardiopulmonary resuscitation during ECLS independently predicted development of CNS complications.

CONCLUSION

Patients who have metabolic acidosis, a bicarbonate or inotrope/vasopressor requirement, cardiopulmonary resuscitation, or a left ventricular assist device before initiation of ECLS are at greater risk for development of CNS complications. After initiation of ECLS, patients who develop renal failure or metabolic acidosis or undergo venoarterial ECLS should be closely monitored for development of CNS complications.

Systemic hypertension associated with venovenous extracorporeal membrane oxygenation for pediatric respiratory failure

BACKGROUND/PURPOSE

Arterial hypertension (HTN) is common in neonates on venoarterial (VA) extracorporeal membrane oxygenation (ECMO), but HTN in pediatric venovenous (VV) ECMO has not been well described. The authors noted HTN in their VV ECMO experience and hypothesized that HTN was associated with fluid status, steroid use, and renal insufficiency.

METHODS

Records of 50 patients receiving VV ECMO for respiratory failure were reviewed. HTN was defined as systolic blood pressure greater than 95th percentile for age for > or =1 hour, unresponsive to sedation/analgesia. Hypertensive index (HI) is defined as total hypertensive hours per total ECMO hours. Fluid status was estimated by a fluid index (FI = total fluid balance during ECMO per ECMO hours per weight).

RESULTS

Forty-seven of 50 patients (94%) had HTN. Median HI was 0.21 (range, 0.01 to 1.0). Thirteen patients had renal insufficiency, 39 received steroids, and 23 received continuous venovenous hemofiltration (CVVH). There was no association between HI and FI, steroid use, or renal insufficiency. Thirty-three patients were treated for HTN, often requiring multiple agents. Bleeding complicated the course of 18 patients, and HI was significantly higher in those patients (P = .03). HI was not different between survivors (37 of 39 with HTN) and nonsurvivors (10 of 11 with HTN).

CONCLUSIONS

Hypertension is a common complication associated with VV ECMO with unclear etiology. HTN was frequently difficult to control. This study emphasizes the need for the development of treatment protocols to decrease the incidence, severity, and associated morbidity. Improved insight into the etiology of HTN associated with pediatric VV ECMO, including evaluation of the renin-angiotensin system, would help guide therapy.

Approaches in the management of acute respiratory failure in children

PURPOSE OF REVIEW

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are conditions that are associated with significant morbidity and mortality in children. There have been no advances in preventing ARDS, but this review highlights strategies directed at minimizing ventilator-induced lung injury and other new adjunctive therapies in the care of these patients.

RECENT FINDINGS

High-frequency oscillatory ventilation, airway pressure release ventilation, and partial liquid ventilation are potential protective ventilatory modes for children with ALI or ARDS. Recruitment maneuvers, prone positioning, and kinetic therapy are all reported to improve oxygenation by opening the lung while positive end-expiratory pressure maintains functional residual capacity. Inhaled nitric oxide and surfactant are used to reduce inspired oxygen concentration and facilitate gas exchange, but their efficacy in ARDS continues to be investigated. Also, early investigations suggest that a specialized enteral formula can be a useful adjunctive therapy by reducing lung inflammation and improving oxygenation. When mechanical ventilation and adjunctive therapies fail, extracorporeal life support continues to be used as a rescue therapy.

SUMMARY

It is likely that a combination of these therapies will maximize treatment and clinical outcomes in the future, but the only way that will be proven is through large controlled clinical trials in pediatric patients.

Outcome of pediatric patients treated with extracorporeal life support after cardiac surgery

BACKGROUND

Extracorporeal life support (ECLS) has been used for over two decades in select patients after cardiac surgery. We previously described factors associated with death in this population. We now review our recent experience to reassess factors related to mortality.

METHODS

All pediatric patients who received ECLS support within 7 days after surgery between July 1995 and June 2001 were examined to describe clinical features associated with survival. We compared the results with our prior report to assess changes in practice and outcome.

RESULTS

Seventy-four patients were followed. Fifty percent survived to discharge. Hospital survival was not significantly related to patient age, cannulation site, or indication. Thirty-five percent of patients required hemofiltration while on ECLS and were significantly less likely to survive (23% vs 65%). A multivariate analysis combining all children from our prior report with the present cohort revealed that patients who received hemofiltration were five times more likely to die (odds ratio 5.01, 95% confidence interval 2.11-11.88). Children with an adequate two-ventricular repair had lower risk of death (odds ratio 0.42, 95% confidence interval 0.19-0.91) after adjusting for patient age, study period, and hours elapsed before initiation of ECLS after surgery.

CONCLUSIONS

Patients with an adequate two-ventricle repair have significantly higher hospital survival, whereas those with single ventricle physiology or need for dialysis have decreased survival.

Impact of extracorporeal membrane oxygenation modality on cytokine release during rescue from infant hypoxia

The treatment of acute respiratory failure in infants by means of extracorporeal membrane oxygenation (ECMO) is thought to be associated with a treatment-related inflammatory reaction, which may deteriorate the underlying disease process. The aim of this study was to compare the venoarterial (VA) and venovenous (VV) modality of ECMO with regard to their pulmonary and serological cytokine release during rescue from acute hypoxia. The inflammatory response was measured in piglets undergoing hypoxic ventilation with a gas mixture of 92% N2 and 8% O2, which were then rescued through VA- (n = 5) or VV-ECMO (n = 5). The effect of cannulation and anesthesia on the inflammatory response was deducted from regularly ventilated control animals (n = 5). The concentrations of the proinflammatory interleukins (IL)-1beta and IL-8 increased in the bronchoalveolar lavage fluid of all groups over a study period of 5 h but were significantly higher (P < 0.05) during VA-ECMO treatment, whereas the anti-inflammatory IL-10 concentrations were significantly higher in the bronchoalveolar lavage fluid of VV-treated animals (P < 0.001). No statistical difference between groups was found in the serum concentrations of cytokines. We conclude that in this animal model rescue from hypoxia by means of the VA modality of ECMO leads to a more pronounced inflammatory reaction of the lung than when applying the VV modality.

Extracorporeal life support for posttraumatic acute respiratory distress syndrome at a children's medical center

BACKGROUND

Primary traumatic injury was considered previously a contraindication for institution of extracorporeal life support because of high risk for persistent or new bleeding. Published experience in adults suggests that extracorporeal membrane oxygenation (ECMO) can successfully support trauma victims with pulmonary failure. The authors reviewed their experience with the use of ECMO in pediatric and adult trauma patients with acute respiratory distress syndrome (ARDS) at a children's medical center.

METHODS

ECMO Center records from 1991 through 2001 (76 children, 8 adults) were reviewed to identify all patients with a primary or secondary ICD-9 diagnostic code of posttraumatic ARDS in addition to documented trauma.

RESULTS

Five children and 3 adults with traumatic injury and ARDS received ECMO support. Seven patients were injured in motor vehicle collisions; one patient suffered a gunshot wound to the chest. Patient ages ranged from 21 months to 29 years (pediatric median, 4 years; range, 21 months to 18 years). Four patients had pre-ECMO laparotomies, including 3 who required splenectomy. Four patients had liver lacerations, 3 had pulmonary contusions, and 1 had a renal contusion. Median ventilation before ECMO was 6 days (range, 2 to 10). Seven of 8 patients were placed on venovenous (VV) ECMO. Seven patients had significant bleeding on ECMO. Patients were treated with blood product replacement, epsilon-aminocaproic acid (EACA), and aprotinin infusions. Surgical intervention was not required for bleeding. Six patients received hemofiltration. Median time on ECMO was 653 hours (range, 190 to 921 hours). Six of 8 patients overall survived (75%). Four of 5 pediatric patients survived.

CONCLUSIONS

Children and adults with severe posttraumatic ARDS can be treated successfully on VV extracorporeal support. Hemorrhage occurs frequently but is manageable.

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

OBJECTIVES

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

DESIGN

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

SETTING

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

PATIENTS

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

INTERVENTIONS

ECMO for acute respiratory failure.

MEASUREMENTS AND MAIN RESULTS

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

CONCLUSIONS

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

The immediate haemodynamic response to the initiation of extracorporeal membrane oxygenation in a piglet model of infant hypoxic respiratory failure

There is evidence that haemodynamic fluctuations on extracorporeal membrane oxygenation (ECMO) increase the risk of cerebral damage. We hypothesized that initiation of venovenous (VV) or venoarterial (VA) ECMO itself causes haemodynamic fluctuations and, thus, established an infant animal ECMO model in order to discuss this hypothesis. Five piglets were cannulated using the jugular and femoral veins (VV group) and five using the jugular vein and carotid artery (VA group). All animals were subjected to hypoxic ventilation (FiO2 8%) for 10 min, leading to a PaO2 of < 40 mmHg, and subsequently rescued by ECMO. The heart rate (HR) and mean arterial blood pressure (MAP) were recorded at 5-min intervals; the arterial blood lactate was measured prior to and after 5 and 10 min of hypoxia, as well as 30, 60 and 120 min after initiation of ECMO. The response to initiation of ECMO was similar in the VV and VA groups with regard to HR and lactate, but differed significantly in MAP. HR decreased significantly from 135 +/- 7 to 103 +/- 6 beats/min (p < 0.05) and from 132 +/- 8 to 84 +/- 9 beats/min (p < 0.01) at 5 min (p = NS) after installation; lactate increased from 1.4 +/- 0.1 to 1.8 +/- 0.2 mmol/l (p = NS) and from 1.4 +/- 0.2 to 1.6 +/- 0.5 mmol/l (p = NS) after 30 min (p = NS); MAP decreased from 80 +/- 5 to 63 +/- 3 mmHg (p = NS) and increased from 75 +/- 4 to 84 +/- 3 mmHg (p = NS) at 5 min (p = 0.001), respectively. The initiation of ECMO is associated with haemodynamic fluctuations in both modalities, which differ with regard to blood pressure reaction.

Pediatric Extracorporeal Life Support After High Frequency Ventilation: Predictors of Survival

Previous studies of extracorporeal life support in pediatric patients have identified variables associated with survival. However, none of these studies focused on extracorporeal life support after failure of high frequency ventilation (HFV). In the present study, we determined variables associated with survival for pediatric respiratory failure patients who received HFV prior to extracorporeal life support, using data reported to the Extracorporeal Life Support Organization Registry from 1992 to 1998. Patients with neonatal diagnoses, immune compromising conditions, or congenital cardiac defects were excluded. The 243 patients who met inclusion criteria had a 58% survival rate (95% CI 48-66%). The mean age was 22 +/- 39 months. Mean duration of mechanical ventilation prior to extracorporeal life support was 6.6 +/- 5.8 days. Venoarterial extracorporeal life support was used in 72% of the patients; venovenous in 28%. The survival rate for the subset of patients with an oxygenation index greater than 42 cm H2O/torr on HFV (n = 122) was not significantly different from the overall sample. We determined that lower mean airway pressure, lower pressure amplitude, decreased oxygenation index, increased PaO2, and increased oxygen saturation on HFV were associated with increased survival in patients who were subsequently treated with extracorporeal life support.

Support of respiratory failure in the pediatric surgical patient

Severe respiratory failure in newborn and pediatric patients is associated with significant morbidity and mortality. Basic science laboratory investigation has led to advances in the understanding of ventilator-induced lung injury and in optimizing the supportive use of conventional ventilation strategies. Over the past few years, progress has been made in alternative therapies for supporting children and adults with severe respiratory failure. This review will focus on recent laboratory and clinical data regarding the techniques of lung protective ventilator strategies, inhaled nitric oxide, liquid ventilation, and extracorporeal life support (ECLS, ECMO). Some of these modalities are commonplace, while others may have much to offer the pediatric clinician if their benefit is clearly demonstrated in future clinical trials.