The outcomes of children with pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

Specific Etiologies Associated With the Multiple Organ Dysfunction Syndrome in Children: Part 1

OBJECTIVE

To describe a number of the conditions associated with multiple organ dysfunction syndrome presented as part of the Eunice Kennedy Shriver National Institute of Child Health and Human Development multiple organ dysfunction syndrome workshop (March 26-27, 2015).

DATA SOURCES

Literature review, research data, and expert opinion.

STUDY SELECTION

Not applicable.

DATA EXTRACTION

Moderated by an expert from the field, issues relevant to the association of multiple organ dysfunction syndrome with a variety of conditions were presented, discussed, and debated with a focus on identifying knowledge gaps and research priorities.

DATA SYNTHESIS

Summary of presentations and discussion supported and supplemented by the relevant literature.

CONCLUSIONS

There is a wide range of medical conditions associated with multiple organ dysfunction syndrome in children. Traditionally, sepsis and trauma are the two conditions most commonly associated with multiple organ dysfunction syndrome both in children and adults. However, there are a number of other pathophysiologic processes that may result in multiple organ dysfunction syndrome. In this article, we discuss conditions such as cancer, congenital heart disease, and acute respiratory distress syndrome. In addition, the relationship between multiple organ dysfunction syndrome and clinical therapies such as hematopoietic stem cell transplantation and cardiopulmonary bypass is also considered. The purpose of this article is to describe the association of multiple organ dysfunction syndrome with a variety of conditions in an attempt to identify similarities, differences, and opportunities for therapeutic intervention.

High-frequency oscillatory ventilation is an effective treatment for severe pediatric acute respiratory distress syndrome with refractory hypoxemia

Background and purpose

Early or primary application of high-frequency oscillatory ventilation (HFOV) has been recently suggested not to offer benefit to patients with acute respiratory distress syndrome (ARDS). However, the rescue effects of HFOV on severe pediatric acute respiratory distress syndrome (PARDS) with hypoxemia refractory to conventional mechanical ventilation (CMV) remain unclear. This study aimed to determine whether severe PARDS children would benefit from HFOV when oxygenation deteriorated on CMV and to identify any potential risk factors related to mortality.

Patients and methods

In a retrospective and observational study, 48 children with severe PARDS between January 2009 and July 2015 were divided into two groups: 26 in HFOV group and 22 in CMV group. Data regarding demographic, underlying conditions, arterial blood gases and clinical outcomes were collected and analyzed.

Results

The arterial partial pressure of oxygen (PaO₂)/fraction of inspiration oxygen (FiO₂) ratio and PaO₂ improved significantly during HFOV, whereas arterial partial pressure of carbon dioxide (PaCO₂) and oxygenation index decreased. There was no statistical difference in the in-hospital mortality between the groups (P=0.367). The odds ratio of survival in HFOV group was 2.74 (95% confidence interval 0.52 to 14.58, P=0.237). The pediatric intensive care unit length of stay and total ventilation duration were longer in HFOV group (P=0.048 and P=0.000, respectively). Vasoactive agents were used more frequently in HFOV group (P=0.007). The incidence of new air leak was similar between the two groups (P=0.674). The presence of multiple organ dysfunction syndrome and heavier body weight were identified as predictors of mortality in the HFOV group (P=0.006 and P=0.020, respectively).

Conclusion

HFOV as an efficient alternative therapy could significantly improve hypoxemia and promote CO₂ removal in severe PARDS children when oxygenation progressively worsens on CMV.

Special considerations for the management of pediatric acute respiratory distress syndrome

INTRODUCTION

Pediatric acute respiratory distress syndrome (ARDS) remains a diagnostic and therapeutic challenge with significant mortality and morbidity. There are limited data to guide identification and management.

AREAS COVERED

The Pediatric Acute Lung Injury Consensus Conference recently proposed pediatric-specific definitions for ARDS and management recommendations. In this review, we discuss aspects of pediatric ARDS that have received more attention over the past few years: high frequency oscillatory ventilation, administration of corticosteroids and functional outcomes. We conducted searches on PubMed, ClinicalKey and Google Scholar using medical subject heading terms and text words related to acute lung injury and ARDS. Expert commentary: The newly proposed definition for pediatric ARDS requires validation for efficacy in diagnosis and risk stratification. At present, there is insufficient evidence to support routine use of high frequency oscillatory ventilation or corticosteroids in pediatric ARDS. Further studies are required to determine the impact of pediatric ARDS on functional outcomes.

Argument against the Routine Use of Steroids for Pediatric Acute Respiratory Distress Syndrome

Steroids have a plausible mechanism of action of reducing severity of lung disease in acute respiratory distress syndrome (ARDS) but have failed to show consistent benefits in patient-centered outcomes. Many studies have confounding from the likely presence of ventilator-induced lung injury and steroids may have shown benefit because administration minimized ongoing inflammation incited by injurious ventilator settings. If steroids have benefit, it is likely for specific populations that fall within the heterogeneous diagnosis of ARDS. Those pediatric patients with concurrent active asthma or reactive airway disease of prematurity, in addition to ARDS, are the most common group likely to derive benefit from steroids, but are poorly studied. With the information currently available, it does not appear that the typical adult or pediatric patient with ARDS derives benefit from steroids and steroids should not be given on a routine basis.

Relevant Outcomes in Pediatric Acute Respiratory Distress Syndrome Studies

Despite distinct epidemiology and outcomes, pediatric acute respiratory distress syndrome (PARDS) is often managed based on evidence extrapolated from treatment of adults. The impact of non-pulmonary processes on mortality as well as the lower mortality rate compared to adults with acute respiratory distress syndrome (ARDS) renders the utilization of short-term mortality as a primary outcome measure for interventional studies problematic. However, data regarding alternatives to mortality are profoundly understudied, and proposed alternatives, such as ventilator-free days, may be themselves subject to hidden biases. Given the neuropsychiatric and functional impairment in adult survivors of ARDS, characterization of these morbidities in children with PARDS is of paramount importance. The purpose of this review is to frame these challenges in the context of the existing pediatric literature, and using adult ARDS as a guide, suggest potential clinically relevant outcomes that deserve further investigation. The goal is to identify important areas of study in order to better define clinical practice and facilitate future interventional trials in PARDS.

BPD Following Preterm Birth: A Model for Chronic Lung Disease and a Substrate for ARDS in Childhood

It has been suggested that pediatric acute respiratory distress syndrome (PARDS) may be a different entity, vis-à-vis adult acute respiratory distress syndrome (ARDS), based on its epidemiology and outcomes. A more pediatric-specific definition of PARDS to include the subgroup of patients with underlying lung (and heart) disease has been proposed. Epidemiological data suggest that up to 13% of the children with ARDS have a history of prematurity and/or underlying chronic lung disease. However, the specific contribution of bronchopulmonary dysplasia (BPD), the most common chronic lung disease in infants, to the development of PARDS is not known. BPD leads to damaged lungs with long-term consequences secondary to disordered growth and immune function. These damaged lungs could potentially act as a substrate, which given the appropriate noxious stimuli, can predispose a child to PARDS. Interestingly, similar biomarkers [KL-6, interleukin (IL)-6, IL-8, sICAM-1, angiopoietin-2, and matrix metalloproteinase-8 and -9] of pulmonary injury have been associated both with BPD and ARDS. Recognition of a unique pattern of clinical symptomatology and/or outcomes of PARDS, if present, could potentially be useful for investigating targeted therapeutic interventions.