Extracorporeal membrane oxygenation therapy in neonates with septic shock

ExtraCorporeal Membrane Oxygenation in the therapy for REfractory Septic shock with Cardiac function Under Estimated (ECMO-RESCUE): study protocol for a prospective, multicentre, non-randomised cohort study

INTRODUCTION

Severe septic cardiomyopathy (SCM) is one of the main causes of refractory septic shock (RSS), with a high mortality. The application of venoarterial extracorporeal membrane oxygenation (ECMO) to support the impaired cardiac function in patients with septic shock remains controversial. Moreover, no prospective studies have been taken to address whether venoarterial ECMO treatment could improve the outcome of patients with sepsis-induced cardiogenic shock. The objective of this study is to assess whether venoarterial ECMO treatment can improve the 30-day survival rate of patients with sepsis-induced refractory cardiogenic shock.

METHODS AND ANALYSIS

ExtraCorporeal Membrane Oxygenation in the therapy for REfractory Septic shock with Cardiac function Under Estimated is a prospective, multicentre, non-randomised, cohort study on the application of ECMO in SCM. At least 64 patients with SCM and RSS will be enrolled in an estimated ratio of 1:1.5. Participants taking venoarterial ECMO during the period of study are referred to as cohort 1, and patients receiving only conventional therapy without ECMO belong to cohort 2. The primary outcome is survival in a 30-day follow-up period. Other end points include survival to intensive care unit (ICU) discharge, hospital survival, 6-month survival, quality of life for long-term survival (EQ-5D score), successful rate of ECMO weaning, long-term survivors' cardiac function, the number of days alive without continuous renal replacement therapy, mechanical ventilation and vasopressor, ICU and hospital length of stay, the rate of complications potentially related to ECMO treatment.

ETHICS AND DISSEMINATION

The trial has been approved by the Clinical Research and Application Institutional Review Board of the Second Affiliated Hospital of Guangzhou Medical University (2020-hs-51). Participants will be screened and enrolled from ICU patients with septic shock by clinicians, with no public advertisement for recruitment. Results will be disseminated in research journals and through conference presentations.

TRIAL REGISTRATION NUMBER

NCT05184296.

Central venoarterial extracorporeal life support in pediatric refractory septic shock: a single center experience

OBJECTIVE

Venoarterial extracorporeal membrane oxygenation (VA ECMO) is recognized as a potential support therapy for pediatric patients with refractory septic shock (RSS). This review aims to report our experience with central VA cannulation in pediatric patients with RSS, and to compare this with peripheral VA ECMO cannulations for this condition at our institution.

DESIGN

Retrospective case series.

SETTING

Pediatric and cardiac intensive care units in an academic pediatric hospital.

PATIENTS

All patients 0-18 years old meeting criteria of RSS placed on VA ECMO between January 2011 and December 2018.

INTERVENTIONS

None.

MEASUREMENTS

Demographics, relevant clinical variables, ECMO run details, and outcomes were collected.

RESULTS

Between 2011 and 2018, 14 children were placed on VA ECMO for RSS. Nine were cannulated centrally, with the rest placed on peripheral VA ECMO. Overall survival to hospital discharge was 57.1% (8/14), with 66.7% of the central cannulation cohort surviving versus 40% in the peripheral cannulation (p = 0.34). Median ECMO duration was 147.1 hours (IQR: 91.9-178.6 hours), with survivors having a median length of 147.1 (IQR: 138.5-185.7) versus non survivors 114.7 hours (IQR: 63.7-163.5), p = 0.48. Overall median ICU length of stay (LOS) was 19 days (IQR: 10.5-42.2). The median % maximum flow achieved on VA ECMO was higher in the central cannulation group at 179.6% (IQR: 154.4-188.1) versus the peripheral with 133.5% (98.1-149.1), p = 0.01. Functional status scale (FSS) was used to capture morbidity. All survivors had a mean increase in their FSS from baseline. In the centrally cannulated group, 50% (4/8) received mediastinal exploration, but none developed mediastinitis. In terms of blood product utilization, the central cannulation received more platelets compared to the peripherally cannulated group (median 15.6 vs 3.3 mL/kg/day, p = 0.03).

CONCLUSION

A central approach to VA ECMO cannulation is feasible and has potential for good patient outcomes in selected patients.

Pediatric and neonatal extracorporeal life support: current state and continuing evolution

The use of extracorporeal life support (ECLS) for the pediatric and neonatal population continues to grow. At the same time, there have been dramatic improvements in the technology and safety of ECLS that have broadened the scope of its application. This article will review the evolving landscape of ECLS, including its expanding indications and shrinking contraindications. It will also describe traditional and hybrid cannulation strategies as well as changes in circuit components such as servo regulation, non-thrombogenic surfaces, and paracorporeal lung-assist devices. Finally, it will outline the modern approach to managing a patient on ECLS, including anticoagulation, sedation, rehabilitation, nutrition, and staffing.

Role of extracorporeal membrane oxygenation in children with sepsis: a systematic review and meta-analysis

BACKGROUND

The benefits of extracorporeal membrane oxygenation (ECMO) in children with sepsis remain controversial. Current guidelines on management of septic shock in children recommend consideration of ECMO as salvage therapy. We sought to review peer-reviewed publications on effectiveness of ECMO in children with sepsis.

METHODS

Studies reporting on mortality in children with sepsis supported with ECMO, published in PubMed, Scopus and Embase from 1972 till February 2020, were included in the review. This study was done in adherence to Preferred Reporting Items for Systematic Review and Meta-Analysis statement after registering the review protocol with PROSPERO. Study eligibility was independently assessed by two authors and disagreements resolved by a third author. Publications were reviewed for quality using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Random-effects meta-analyses (DerSimonian and Laird) were conducted, and 95% confidence intervals were computed using the Clopper-Pearson method. Outliers were identified by the Baujat plot and leave-one-out analysis if there was considerable heterogeneity. The primary outcome measure was survival to discharge. Secondary outcome measures included hospital length of stay, subgroup analysis of neonatal and paediatric groups, types and duration of ECMO and complications .

RESULTS

Of the 2054 articles screened, we identified 23 original articles for systematic review and meta-analysis. Cumulative estimate of survival (13 studies, 2559 patients) in the cohort was 59% (95%CI: 51-67%). Patients had a median length of hospital stay of 28.8 days, median intensive care unit stay of 13.5 days, and median ECMO duration of 129 h. Children needing venoarterial ECMO (9 studies, 208 patients) showed overall pooled survival of 65% (95%CI: 50-80%). Neonates (< 4 weeks of age) with sepsis needing ECMO (7 studies, 85 neonates) had pooled survival of 73% (95%CI: 56- 87%). Gram positive organisms were the most common pathogens (47%) in septic children supported with ECMO.

CONCLUSION

Survival rates of children with sepsis needing ECMO was 59%. Neonates had higher survival rates (73%); gram positive organisms accounted for most common infections in children needing ECMO. Despite limitations, pooled survival data from this review indicates consideration of ECMO in refractory septic shock for all pediatric age groups.

Extracorporeal Membrane Oxygenation for Group B Streptococcal Sepsis in Neonates: A Retrospective Study of the Extracorporeal Life Support Organization Registry

OBJECTIVES

Neonatal group B streptococcal sepsis remains a leading cause of neonatal sepsis globally and is characterized by unique epidemiologic features. Extracorporeal membrane oxygenation has been recommended for neonatal septic shock refractory to conventional management, but data on extracorporeal membrane oxygenation in group B streptococcal sepsis are scarce. We aimed to assess outcomes of extracorporeal membrane oxygenation in neonates with group B streptococcal sepsis.

DESIGN

Retrospective study of the international registry of the Extracorporeal Life Support Organization.

SETTING

Extracorporeal membrane oxygenation centers contributing to Extracorporeal Life Support Organization registry.

PATIENTS

Patients less than or equal to 30 days treated with extracorporeal membrane oxygenation and a diagnostic code of group B streptococcal sepsis between January 1, 2007, and December 31, 2016.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In-hospital mortality was the primary outcome. Univariable and multivariable logistic regression models to predict mortality were established. One hundred ninety-two runs in 191 neonates were identified meeting eligibility criteria, of which 55 of 191 (29%) died. One hundred thirty-seven (71%) were treated with venoarterial extracorporeal membrane oxygenation. One hundred sixty-nine runs (88%) occurred during the first week of life for early-onset sepsis and 23 (12%) after 7 days of life. The in-hospital mortality for extracorporeal membrane oxygenation used after 7 days of life was significantly higher compared with early-onset sepsis (65% vs 24%; p < 0.01). In addition, lower weight, lower pH, lower bicarbonate, and surfactant administration precannulation were significantly associated with mortality (p < 0.05). Adjusted analyses confirmed that age greater than 7 days, lower weight, and lower pH were associated with higher mortality (p < 0.05). One hundred fifty-one of 192 runs (79%) experienced a major complication. The number of major complications during extracorporeal membrane oxygenation was associated significantly with mortality (p < 0.001; adjusted odds ratio, 1.27 [1.08-1.49; p = 0.004]).

CONCLUSIONS

This large registry-based study indicates that treatment with extracorporeal membrane oxygenation for neonatal group B streptococcal sepsis is associated with survival in the majority of patients. Future quality improvement interventions should aim to reduce the burden of major extracorporeal membrane oxygenation-associated complications which affected four out of five neonatal group B streptococcal sepsis extracorporeal membrane oxygenation patients.

Defining benefit threshold for extracorporeal membrane oxygenation in children with sepsis-a binational multicenter cohort study

BACKGROUND

The surviving sepsis campaign recommends consideration for extracorporeal membrane oxygenation (ECMO) in refractory septic shock. We aimed to define the benefit threshold of ECMO in pediatric septic shock.

METHODS

Retrospective binational multicenter cohort study of all ICUs contributing to the Australian and New Zealand Paediatric Intensive Care Registry. We included patients < 16 years admitted to ICU with sepsis and septic shock between 2002 and 2016. Sepsis-specific risk-adjusted models to establish ECMO benefit thresholds with mortality as the primary outcome were performed. Models were based on clinical variables available early after admission to ICU. Multivariate analyses were performed to identify predictors of survival in children treated with ECMO.

RESULTS

Five thousand sixty-two children with sepsis and septic shock met eligibility criteria, of which 80 (1.6%) were treated with veno-arterial ECMO. A model based on 12 clinical variables predicted mortality with an AUROC of 0.879 (95% CI 0.864-0.895). The benefit threshold was calculated as 47.1% predicted risk of mortality. The observed mortality for children treated with ECMO below the threshold was 41.8% (23 deaths), compared to a predicted mortality of 30.0% as per the baseline model (16.5 deaths; standardized mortality rate 1.40, 95% CI 0.89-2.09). Among patients above the benefit threshold, the observed mortality was 52.0% (13 deaths) compared to 68.2% as per the baseline model (16.5 deaths; standardized mortality rate 0.61, 95% CI 0.39-0.92). Multivariable analyses identified lower lactate, the absence of cardiac arrest prior to ECMO, and the central cannulation (OR 0.31, 95% CI 0.10-0.98, p = 0.046) as significant predictors of survival for those treated with VA-ECMO.

CONCLUSIONS

This binational study demonstrates that a rapidly available sepsis mortality prediction model can define thresholds for survival benefit in children with septic shock considered for ECMO. Survival on ECMO was associated with central cannulation. Our findings suggest that a fully powered RCT on ECMO in sepsis is unlikely to be feasible.

Venoarterial extracorporeal membrane oxygenation support for neonatal and pediatric refractory septic shock: more than 15 years of learning

The objective of the study was to report our institutional experience in the management of children and newborns with refractory septic shock who required venoarterial extracorporeal membrane oxygenation (VA ECMO) treatment, and to identify patient-and infection-related factors associated with mortality. This is a retrospective case series in an intensive care unit of a tertiary pediatric center. Inclusion criteria were patients ≤ 18 years old who underwent a VA ECMO due to a refractory septic shock due to circulatory collapse. Patient conditions and support immediately before ECMO, analytical and hemodynamic parameter evolution during ECMO, and post-canulation outcome data were collected. Twenty-one patients were included, 13 of them (65%) male. Nine were pediatric and 12 were newborns. Median septic shock duration prior to ECMO was 29.5 h (IQR, 20-46). Eleven patients (52.4%) suffered cardiac arrest (CA). Neonatal patients had worse Sepsis Organ Failure Assessment (SOFA) score, Oxygenation Index and PaO₂/FiO₂ ratio, blood gas analysis, lactate levels, and left ventricular ejection fraction compared to pediatric patients. Survival was 33.3% among pediatric patients (60% if we exclude pneumococcal cases) and 50% among newborns. Hours of sepsis evolution and mean airway pressure (MAP) prior to ECMO were significantly higher in the non-survivor group. CA was not a predictor of mortality. Streptococcus pneumoniae infection was a mortality risk factor. There was an improvement in survival during the second period, from 14.3 to 57.2%, related to shorter sepsis evolution before ECMO placement, better candidate selection, and greater ECMO support once the patient was placed.

CONCLUSION

Patients with refractory septic shock should be transferred precociously to a referral ECMO center. However, therapy should be used with caution in patients with vasoplegic pattern shock or S. pneumoniae sepsis. What is Known: • Children with refractory septic shock have significant mortality rates, and although ECMO is recommended, overall survival is low. • There are no studies regarding characteristics of infections as predictors of pediatric survival in ECMO. What is New: • Septic children should be transferred precociously to referral ECMO centers during the first hours if patients do not respond to conventional therapy. • Treatment should be used with caution in patients with vasoplegic pattern shock or S. pneumoniae sepsis.

Extracorporeal life support for adults with refractory septic shock

OBJECTIVE

Although the use of extracorporeal membrane oxygenation (ECMO) in shock patients is increasing worldwide, studies concerning this treatment for adult septic shock are limited. This study aimed to analyze the outcome of venoarterial ECMO in adult patients with septic shock refractory to conventional treatment.

METHODS

A total of 71 consecutive patients who presented with septic shock and underwent venoarterial ECMO were reviewed. Clinical parameters were compared between survivors and nonsurvivors. Weaning and survival outcomes of these patients were compared with the control group of 253 patients who received venoarterial ECMO for cardiogenic shock.

RESULTS

The mean age was 56.0 ± 12.3 years. Of the 71 septic shock patients, 11 (15.5%) were successfully weaned from ECMO after a median of 7.9 [interquartile range (IQR), 6.3-10.2] days, 5 of whom (7.0%) survived to discharge. Pre- and 6 hours post-procedural lactate levels were significantly higher in the nonsurvivors (11.6 [IQR, 7.5-15.0] vs 5.8 [IQR, 4.3-5.9], P = .036; 15.0 [IQR, 11.1-15.0] vs 5.2 [IQR, 4.7-5.4], P = .002). Rates of successful weaning from venoarterial ECMO (15.5% vs 45.5%), and of survival up to hospital discharge (7.0% vs 28.9%) were significantly lower in septic shock than in cardiogenic shock patients (n = 253; P < .001).

CONCLUSIONS

Outcomes of ECMO in refractory septic shock patients were poor with a very low probability of survival. This finding raises questions concerning the utility of applying ECMO for medically refractory septic shock. Elevated arterial lactate levels pre- and post-ECMO were associated with risk of in-hospital death. Further large-scale studies are needed to validate the results of this study.

Pathogens and outcomes in pediatric septic shock patients supported by extracorporeal membrane oxygenation

BACKGROUND

Refractory septic shock is the leading cause of mortality in children. There is limited evidence to support extracorporeal membrane oxygenation (ECMO) use in pediatric septic shock. We described the etiology and outcomes of septic patients in our institution and attempted to find predictive factors.

METHODS

We retrospectively reviewed 55 pediatric patients with septic shock who required ECMO support in a tertiary medical center from 2008 to 2015. Septic shock was defined as culture proved or clinical suspected sepsis with hypotension or end-organ hypoperfusion. ECMO would be applied when pediatric advanced life support steps were performed thoroughly without clinical response. Patient's demographics, laboratory parameters before and after ECMO, and outcomes were analyzed.

RESULTS

Among 55 children with ECMO support, 31% of them survived on discharge. For 25 immunocompromised patients, causal pathogens were found in 17 patients: 7 due to bacteremia, 9 with preexisting virus infections and one with invasive fungal infection. Among 30 previously healthy patients, causal pathogens were found in 18 patients: 10 due to bacteremia (the most common was pneumococcus), 7 with preexisting virus infections including influenza (n = 4), adenovirus (n = 2), RSV, and 1 patient had mixed virus and bacterial infections. Predictive factors associated with death were arterial blood gas pH, CO₂ and Glasgow Coma Scale (p < 0.05). SOFA score was a valuable predictive scoring system for outcome prediction (p < 0.05).

CONCLUSIONS

Pediatric patients with refractory septic shock had high mortality rate and ECMO could be used as a rescue modality, and SOFA score could be applied to predict outcomes.

Infections and Extracorporeal Membrane Oxygenation: Incidence, Therapy, and Outcome

The objective is to assess the influence of infections and the microbiological spectrum on the general outcome of patients undergoing therapy with extracorporeal devices (ECDs), extracorporeal membrane oxygenation, extracorporeal life support, and pumpless extracorporeal lung assist. We performed a single-center, retrospective analysis of 99 patients receiving ECD. Infections requiring ECD, nosocomial infections occurring during treatment, the use of guideline-based antiinfective therapies, and patient outcomes were described and statistically analyzed. We analyzed 88 patients-survivors and nonsurvivors-and subdivided the infections into primary and nosocomial infections. The median patient age was 54.0 years, 85.2% were men, and 45 (51.1%) survived. Surviving ECD patients had a higher risk of nosocomial infection because of their prolonged hospital stay. Our results indicated that early, focused, antiinfective therapy was important to avoid severe infection complications. Infections causing sepsis and multiorgan dysfunction were negatively associated with outcome and successful weaning of ECD. The percentages and types of pathogens in the ECD cohort did not differ from the general colonization of intensive care units. Because a significant correlation between pathogens, infections, and outcome was not detected, we recommend focusing on clinical parameters to decide whether patients will benefit from ECD support.

Venoarterial extracorporeal membrane oxygenation support for neonatal and pediatric refractory septic shock

Objective:

To report our institutional experience of veno-arterial extracorporeal membrane oxygenation (VA ECMO) in children with refractory septic shock.

Materials and Methods:

We retrospectively reviewed our ECMO database to identify patients who received VA ECMO for septic shock from January 2004 to June 2013 at our Pediatric Intensive Care Unit in Armand-Trousseau Hospital. We included all neonates and children up to the age of 18 years who received VA ECMO for septic shock. For each patient, we collected the pre-ECMO inotrope score, clinical circulatory and ventilatory parameters, infecting organism, ECMO duration and complications, and length of hospital stay.

Main Results:

The study included 14 neonates and 8 older children (the pediatric population, with a mean age of 30 months, range: 1–113 months). Survival was 64% among newborns and 50% among pediatric patients. Multiorgan failure or severity scores did not show any correlation with mortality (Pediatric Logistic Organ Dysfunction score, P = 0.94; the score for neonatal acute physiology-perinatal extension II, P = 0.34). In the pediatric population, the inotrope score was higher in the survivor group (127.5 vs. 332.5, P = 0.07). Blood samples taken shortly before cannulation showed that pH (P = 0.27), lactate level (P = 0.33), PaO2/FiO2 ratio (P = 0.49), or oxygenation index (P = 0.35) showed no correlation to success or failure of ECMO.

Conclusion:

ECMO can be safely used to resuscitate and support children with refractory septic shock. We recommend that patients with oliguria whose lactate level has not decreased within 6 h of starting maximum drug therapy be transferred to an ECMO referral center.

Pediatric Extracorporeal Membrane Oxygenation: An Introduction for Emergency Medicine Physicians

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) therapy has supported critically ill pediatric patients in the intensive care unit setting with cardiac and respiratory failure. This therapy is beginning to transition to the emergency department setting.

OBJECTIVE OF REVIEW

This article describes the fundamentals of ECMO and familiarizes the emergency medicine physician with its use in critically ill pediatric patients.

DISCUSSION

ECMO can be utilized as either venoarterial (VA) or venovenous (VV), to support oxygenation and perfusion in respiratory failure, sepsis, cardiac arrest, and environmental hypothermia.

Pediatric extracorporeal life support in specialized situations

OBJECTIVES

The purpose of this review was to provide a systematic review of the literature regarding the use of extracorporeal life support (ECLS) in various specialized conditions, as part of the Pediatric Cardiac Intensive Care Society/Extracorporeal Life Support Organization Joint Statement on Mechanical Circulatory Support.

DATA SOURCES

MEDLINE and PubMed.

STUDY SELECTION

Searches for published abstracts and articles were conducted using the following MeSH terms: extracorporeal life support, extracorporeal membrane oxygenation, or mechanical support, and pediatric or children.

DATA EXTRACTION

Abstracts of all articles including case reports were reviewed; the full article was reviewed if the abstract indicated that it focused on extracorporeal life support for conditions other than primary respiratory disease or persistent pulmonary hypertension of the newborn and described outcomes such as survival to hospital discharge. Studies with potential overlapping patients were highlighted in the review process and summary results.

DATA SYNTHESIS

Classification of recommendations and level of evidence are expressed in the American College of Cardiology Foundation/American Heart Association format.

CONCLUSIONS

The majority of specialized situations where extracorporeal life support is used fall into the category of class II-III evidence. Class I indications for extracorporeal life support in the pediatric population include myocarditis and in the context of acute interventions in the cardiac catheterization laboratory.

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

BACKGROUND/PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Central extracorporeal membrane oxygenation for refractory pediatric septic shock

OBJECTIVE

To demonstrate positive outcome, to achieve higher flow rates, and to reverse shock more quickly by implementing central extracorporeal membrane oxygenation (ECMO) in children with refractory septic shock. Children hospitalized with sepsis have significant mortality rates. The development of shock is the most important risk factor for death. For children with septic shock refractory to all other forms of therapy, ECMO has been recommended but estimated survival is <50% and the best method of applying the technology is unknown. In recent years, our institutional practice has been to cannulate children with refractory septic shock directly through the chest (central, atrioaortic ECMO) to achieve higher blood flow rates.

DESIGN

Retrospective case series.

SETTING

Intensive care unit of a tertiary referral pediatric hospital.

PATIENTS

Twenty-three children with refractory septic shock who received central ECMO primarily as circulatory support.

INTERVENTIONS

Central ECMO.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure was survival to hospital discharge. Pre-ECMO circulatory and ventilatory parameters, infecting organism, duration and complications of ECMO and length of hospital stay were also collected. Twenty-three patients (median: age, 6 yrs; weight, 20 kg) over a 9-yr period were included. All patients had microbiological evidence of infection, and meningococcemia was the most common diagnosis. Twenty-two (96%) patients had failure of at least three organ systems, and all patients received at least two inotropes with a mean inotrope score of 82.2 (sd, 115.6). Eight (35%) patients suffered cardiac arrest and required external cardiac massage before ECMO. Eighteen (78%) patients survived to be decannulated off ECMO, and 17 (74%) children survived to hospital discharge. Higher pre-ECMO arterial lactate levels were associated with increased mortality (11.7 mmol/L in nonsurvivors vs. 6.0 mmol/L in survivors, p = .007).

CONCLUSIONS

Central ECMO seems to be associated with better survival than conventional ECMO and should be considered by clinicians as a viable strategy in children with refractory septic shock.

Extracorporeal Therapies in the Treatment of Sepsis: Experience and Promise

Desire to restore the balance of body elements has enamored physicians since the ancient practice of bloodletting. More recently, extracorporeal techniques have been employed in both adults and children in treating sepsis. Extracorporeal therapies include continuous renal replacement (CRRT), plasma-based removal techniques, and extracorporeal membrane oxygenation (ECMO). These treatments could theoretically 1) provide immunohomeostasis of pro- and anti-inflammatory cytokines and other sepsis mediators, 2) decrease organ microthrombosis through removal of pro-coagulant factors and modulating the impaired septic coagulation response in sepsis, and 3) provide mechanical support of organ perfusion during the acute septic episode to allow time for response to traditional sepsis therapies and antimicrobials. CRRT is beneficial in managing fluid overload and acute renal failure in sepsis. Removal of sepsis mediators through the technique is variable, and the outcome impact of CRRT on sepsis has not been definitively determined. High-flow CRRT has demonstrated benefit in septic adults. Intriguing early results suggest that plasma exchange could improve outcomes in both adults and children. Based on experience, ECMO is recommended for refractory septic shock in neonates and should be considered for use in children. Ongoing trials may help determine whether the promise of extracorporeal therapies translates into outcome improvement in septic children.

Cardiopulmonary outcome of neonatal extracorporeal membrane oxygenation at ages 10–15 years

OBJECTIVE

The purpose of this study was to evaluate the long-term cardiopulmonary outcome at ages 10-15 yrs following neonatal extracorporeal membrane oxygenation (ECMO). The specific aims of the study were to assess baseline aerobic capacity, cardiac function, and pulmonary function in neonatal ECMO survivors using graded exercise testing, echocardiography, and pulmonary function tests.

DESIGN

Cohort study.

SETTING

Exercise and pulmonary function laboratories of a large children's hospital.

PATIENTS

Seventeen 10- to 15-yr-old children treated with ECMO as neonates for meconium aspiration syndrome and 17 age-matched healthy controls.

INTERVENTIONS

Children were evaluated by use of physical exam, electrocardiogram, echocardiogram, treadmill stress test, and pulmonary function tests.

MEASUREMENTS AND MAIN RESULTS

Average weight, height, and age were similar between the groups. Both pre- and postexercise pulmonary function tests revealed air trapping and mild lower airway obstruction in the ECMO group, compared with mean pulmonary functions in the normal range for the control group. The mean forced expiratory volume in 1 sec, the forced expiratory flow between 25% and 75% of vital capacity, and the ratio between residual volume and total lung capacity were significantly different between the ECMO group and the control group. Although the ECMO group exhibited baseline and postexercise lung function abnormalities, there were no differences in maximal oxygen consumption between the two groups and all subjects reached anaerobic threshold. By regression analysis, the gestational age, duration of oxygen, and exercise score were significantly correlated with baseline lung function, using forced expiratory flow between 25% and 75% of vital capacity as the dependent variable.

CONCLUSIONS

Despite abnormalities in baseline and postexercise pulmonary functions, ECMO graduates have similar aerobic capacity to age-matched healthy controls. The most significant factor in predicting long-term pulmonary outcome in ECMO graduates is the duration of oxygen use following decannulation.

Management of sepsis and septic shock in infants and children

Sepsis and septic shock constitute an important cause of morbidity and mortality in critically ill children. Thus, the systemic response to infection and its management remains a major challenge in clinical medicine. Apart from antibiotic administration, the majority of available therapies are limited to supportive strategies, although considerable efforts are being undertaken to devise innovative approaches that modulate host inflammatory responses. In suspected sepsis, 2 or 3 days' empiric antibiotic therapy should begin immediately after cultures have been obtained without awaiting results. Antibiotics should be re-evaluated when the results of the cultures and susceptibility tests are available. The initial antibiotic (combination) is determined by the likely causative agent, susceptibility patterns within a specific institution, CNS penetration, toxicity, and the patient's hepatic and renal function. The likely offending micro-organism in turn depends primarily on the patient's age, coexistence of any premorbid condition leading to impaired immune response, and the presenting signs and symptoms. Close attention to cardiovascular, respiratory, fluid and electrolyte, haematological, renal and metabolic/nutritional support is essential to optimise outcome. Fluid resuscitation is of utmost importance to overcome hypovolaemia on the basis of a diffuse capillary leak. Monitoring and normalisation of the heart rate is essential. In case of nonresponse to fluid resuscitation, inotropic and vasoactive agents are commonly used to increase cardiac output, maintain adequate blood pressure and enhance oxygen delivery to the tissue. Because respiratory distress syndrome is seen in about 40% of critically ill children with septic shock, increased inspired oxygen is essential. To provide optimal relief from respiratory muscle fatigue and facilitate the provision of positive airway pressure, early intubation and mechanical ventilation should be considered. Renal support is essential to avoid prolonged renal shutdown in hypoperfusion states. Haematological support comprises replacement therapy of clotting factors to overcome disseminated intravascular coagulation. Metabolic support may include glucose support, extraction of ammonia from the body and recognition of liver dysfunction. Nutritional support may modify the inflammatory host response, and early enteral feeding can improve outcome in critical illness. To date, glucocorticoid and non-glucocorticoid anti-inflammatory agents have not shown significant benefit in septic patients.

Septic shock

Although our understanding of molecular events in septic shock is growing exponentially, bedside management has changed only incrementally over the last 20 years. In pediatric and adult patients alike, treatment continues to be largely supportive. Morbidity and mortality, though gradually improving, continue to be high. The major similarities, as well as the minor differences, between pediatric and adult septic shock are reviewed in this article, with an emphasis on current clinical practice and recent clinical investigations of novel therapies.

Results of extracorporeal membrane oxygenation in children with sepsis. The Extracorporeal Life Support Organization

BACKGROUND

Despite good results in neonates, extracorporeal membrane oxygenation (ECMO) is less well accepted in pediatric patients. Older children frequently undergo ECMO for severe bacterial, viral, or aspiration pneumonia and many have coexisting systemic sepsis. We reviewed data from a national registry to study the influence of sepsis on survival from ECMO.

METHODS

Six hundred fifty-five patients (aged 2 weeks to 17 years) with respiratory failure treated with ECMO were divided into two groups by the presence (n = 76) or absence (n = 579) of sepsis. Groups were compared by univariate analysis and by multivariate logistic regression that considered 10 additional pre-ECMO variables (age, sex, weight, arterial blood gas results, ventilator parameters, and renal failure).

RESULTS

By univariate analysis, survival was lower in septic children (36.8% versus 51.6%; p < 0.02). However, by multivariate analysis, sepsis was not an independent survival predictor (odds ratio, 0.578; 95% confidence interval, 0.288-1.162; p = 0.12). The ECMO complications predicted by the presence of sepsis included (1) seizures, (2) other neurologic complications, and (3) infection at other sites (all p < 0.05).

CONCLUSIONS

Systemic sepsis does not independently influence survival in pediatric ECMO. This therapy should not be withheld solely because of sepsis, although neurologic complications may occur more frequently.

The use of extracorporeal membrane oxygenation in patients with gram-negative or viral sepsis

To evaluate the use of extracorporeal membrane oxygenation (ECMO) in patients with Gram-negative or viral sepsis, a survey of ECMO centres comprising the Extracorporeal Life Support Organization was conducted. Data collected from neonatal and paediatric intensive care units included patient demographics, indicators of infection, presence of cardiac instability and respiratory criteria for ECMO. One-hundred-and-seven patients with documented sepsis were divided into survivors and nonsurvivors. Prior to ECMO, the patients with a persistent metabolic acidosis (p < 0.008) and/or hypotension requiring more than two inotropic agents (p < 0.02) to support blood pressure were less likely to survive. Also, patients with Gram-positive infections (77%) were more likely to survive their ECMO course than those with Gram-negative (60%) or viral infections (40%). Although survival is less in septic infants than in infants with traditional respiratory failure placed on ECMO, sepsis should not be a contraindication to the use of ECMO. The parents should be informed of the chances of survival with each type of sepsis or respiratory infection (if known), so that a truly informed decision can be made by the parents. We feel that the additional information regarding Gram-negative and viral sepsis should assist the clinician in this goal.

Use of extracorporeal membrane oxygenation in the septic neonate

Extracorporeal membrane oxygenation (ECMO) is widely used for cardiopulmonary support in neonates with cardiopulmonary failure secondary to overwhelming sepsis. The purpose of this study was to examine the effects of culture status on the eventual outcome of septic neonates requiring ECMO support. Data from the Extracorporeal Life Support Organization (ELSO) for the tears 1990 through 1992 inclusive were collected and analyzed for all neonates with a primary diagnosis of sepsis. Records were reviewed for gestational age, birth weight, culture status and isolated organism, last arterial blood gas before beginning ECMO, hemorrhagic complications during bypass, and overall survival. Gram-positive sepsis accounted for 85% of positive cultures. Group B streptococcus (GBS) and Escherichia coli were the most commonly isolated organisms (GBS: 95% of all gram-positive sepsis; E coli: 76% of all gram-negative sepsis) from culture-positive patients. Culture-negative patients were found to have a significantly lower mortality rate compared with culture positive patients (16.6% versus 26.9%, P < .001). The incidence of intracranial hemorrhage (ICH) was greater in culture-positive neonates when compared with culture negative (27.6% versus 20.1%, P < .05). There was no difference in the incidence of ICH or eventual outcome between gram-positive and gram-negative sepsis. The culture-positive, septic neonate who requires ECMO support appears to be at an increased risk for intracranial hemorrhage and death. Intracranial hemorrhage appears to be the primary factor affecting survival in these patients. The etiologic organism does not affect the incidence of ICH or outcome. Frequent head ultrasounds and strict control of coagulation parameters are recommended in this patient population.

Neonatal extracorporeal membrane oxygenation complicated by sepsis. Extracorporeal Life Support Organization

The onset of sepsis in neonates while on extracorporeal membrane oxygenation (ECMO) may portend adverse results. Nevertheless, ECMO has been used as a therapy in the management of septic conditions. This study assessed morbidity and mortality in neonates in whom septic complications developed while they were on ECMO. Of 5,123 neonates in the Extracorporeal Life Support Organization Registry undergoing ECMO for nonseptic indications, 217 patients had development of septic complications. A multivariate logistic regression analysis that considered 15 pre-ECMO criteria was performed to evaluate outcome. Mortality was higher in the septic group (35% versus 17%; p < 0.002) and ECMO duration averaged 85 hours longer (p < 0.001). Septic neonates had a greater frequency of complications including seizures, gastrointestinal bleeding, renal dysfunction, and metabolic problems (all p < 0.05). Transfusion requirements were doubled. Oxygenator thrombi and hemofilter malfunction occurred more often in septic patients (p < 0.03). New strategies to prevent sepsis and associated thrombotic and metabolic complications may be indicated. A critical reappraisal of continued aggressive support may be warranted when septic complications develop in neonates during ECMO.

Results of extracorporeal membrane oxygenation in neonates with sepsis. The Extracorporeal Life Support Organization experience

Use of extracorporeal membrane oxygenation for treatment of respiratory failure caused by sepsis is controversial because of concerns over survival benefit and hemorrhage-related complications. To evaluate the impact of the primary diagnosis of sepsis on outcome, we reviewed data from 6853 neonates in the Extracorporeal Life Support Organization Registry and defined two groups: group 1 (n = 1060), all patients undergoing extracorporeal membrane oxygenation with a primary diagnosis of sepsis; group 2 (n = 5793), those with any other primary diagnosis. A multivariate logistic regression analysis that considered 15 variables present before extracorporeal membrane oxygenation (including age, sex, birth weight, prior cardiopulmonary arrest, arterial blood gas results, and ventilator settings) was used to compare outcomes between groups. Survival was not different between the two groups (77%, group 1; 82%, group 2; p = 0.2480), although lung recovery was less frequent in the patients with sepsis (p = 0.0185). Group 1 had a higher incidence of complications including seizures (odds ratio 1.446, p = 0.0346), cerebral infarct or hemorrhage (2.310, p = 0.0001), need for dialysis (1.478, p = 0.0131), hypernatremia (2.089, p = 0.0019), hyperbilirubinemia (2.423, p = 0.0001), and dobutamine use (1.918, p = 0.0001). Neonates with sepsis are more likely to have neurologic, renal, and metabolic complications from extracorporeal membrane oxygenation but may still achieve a survival benefit equivalent to those without sepsis. From these data, extracorporeal membrane oxygenation should not be withheld from neonates solely on the basis of sepsis. Rather, management strategies should focus on limiting the incidence or severity of the common complications.

Effects of synchronous pulsatile extracorporeal membrane oxygenation in an endotoxin-induced shock model: an experimental study

A synchronous pulsatile venoarterial device for extracorporeal membrane oxygenation (ECMO) was designed to accomplish more effective circulatory support for neonates. The effect of this device was studied using an endotoxin-induced shock model, compared with conventional nonpulsatile ECMO. Twenty puppies weighing 1.6 to 4.0 kg were given endotoxin (5 mg/kg) intravenously. Thirty minutes after the administration of endotoxin, 10 were placed on pulsatile ECMO, and the others were placed on nonpulsatile ECMO, and they were studied for an additional 180 min. Peak blood pressure, arterial pH, base excess, and renal blood flow were significantly higher in the pulsatile group than in the nonpulsatile group. Serum lactate and serum noradrenaline were significantly lower in the pulsatile group than in the nonpulsatile group. These results indicate that pulsatile ECMO may provide more effective cardiopulmonary support in the treatment of neonates with serious circulatory failure that has failed to be supported by nonpulsatile ECMO.