ECMO in CDH: Is there a role?

Abstract

Despite wide use and decades of experience, survival of congenital diaphragmatic hernia (CDH) patients treated with extra-corporeal membrane oxygenation (ECMO), as reported by the extra-corporeal life support organization (ELSO), remains unchanged at 50%. High-survival rates both with and without utilizing ECMO have been reported, fueling questions about the utility of ECMO support in this difficult population. This review looks at data from the Congenital Diaphragmatic Hernia Study Group and individual center reports, to evaluate the role of ECMO in CDH, focusing on defining the patients most likely to benefit, and discussing how those benefits can best be achieved. These data show that ECMO improves survival in those CDH patients who are most severely affected, but potential complications of ECMO delivery outweigh benefit in patients with less severely affected. Improved results can be expected by minimizing ECMO complications, and by improving rates of CDH repair in patients that require ECMO.

Introduction

In 1977, German et al.¹ reported the first four CDH patients supported with ECMO, of which one survived. Four decades later, CDH is the most common indication for ECMO in neonates.² Despite its wide availability and use, however, many remain unsure of the utility and benefit of this invasive support in this most difficult population. Multiple centers report excellent survival results using ECMO in 35–50% in their CDH population, but in stark contrast, other centers report very good results using ECMO sparingly, if at all. Are these experiences comparable? Several monographs specifically addressing this question of utility of ECMO in CDH have failed to derive clear conclusions.3, 4

The goal of this review is to first address then go beyond the binary question of whether ECMO improves survival in CDH, asking for which CDH patients does ECMO increase survival, how are those results best obtained, and can those results be improved? Is there an outcome difference in veno-venous (VV) versus veno-arterial (VA) ECMO in CDH? What is the optimal timing for CDH repair in the ECMO patient? Unfortunately, reporting of risk stratification data to allow direct comparison of results between series is insufficient in most reports. The task is further complicated by the fact that the ultimate survival success of ECMO in CDH is affected not only by the quality of the ECMO, but also by what comes before and after the ECMO run.

In addressing these questions, we will look to published data from the Congenital Diaphragmatic Hernia Study Group, and from individual center reports focusing on contemporary series that report high-survival rates both with, and without utilizing ECMO. We will also look at how overall treatment strategies affect CDH–ECMO outcomes, specifically the role of patient selection, ventilator support strategies, type of ECMO, and importantly, how timing of surgical repair affects CDH–ECMO outcomes.