**1. Introduction**

ECMO is a cardiopulmonary bypass circuit to support patients in severe cardiac and/or respiratory failure. It is an advanced life support therapy for patients at high risk of dying from their respiratory or cardiac disease. Extracorporeal life support, while life-saving in many instances, can pose serious risks and is associated with several neurologic complications. In this chapter, we will review some of the more common neurologic adverse events seen in patients on extracorporeal membrane oxygenation (ECMO), as well as review some of the neuromonitoring modalities available for early recognition of neurologic morbidity. Based on a recent report from the Extracorporeal Life Support Organization (ELSO), the current survival to discharge after ECMO ranges from 28% for adult ECPR patients to 73% for neonatal respiratory ECMO [1]. As survival after ECMO improves with advances in technologies and patient care, there is ever increasing emphasis placed on reducing morbidity experience by survivors.

Majority of the literature on neurologic injuries come from analyses of the ELSO Registry and single center experiences. The ELSO registry currently collects limited information on presence of seizures (clinical or EEG confirmed), central nervous system (CNS) hemorrhages (intraventricular or parenchymal) as determined by ultrasound (US), Computed tomography (CT) or Magnetic Resonance Imaging (MRI); diffuse ischemia or CNS infarction; need for neurosurgical intervention, and brain death on ECMO [2]. In spite of advances in ECMO circuitry, anticoagulation, and clinical management, the rate of occurrence of neurologic injury has not changed in recent times [3].

ECMO was first trialed on a neonate and the success with that patient gradually spread its popularity among the neonatal and eventually pediatric patient

populations [4]. The H1N1 influenza pandemic in 2009 is primarily credited for the adoption of ECMO in many adult centers and its use in adults has grown exponentially since. While most of the early data came from neonates, more recent studies on neurologic injuries in adults are informing care of the ECMO patient. As ECMO is becoming more ubiquitously used, this chapter discusses neurologic complications noted across the age spectrum. However risk factors, types of complications and management often vary by patient population, from neonates to adults. Effort has been made to specify if certain descriptions are only applicable to a certain age group, and information may not be relevant for all ages.
