Neuroprognostication of hypoxic–ischaemic coma in the therapeutic hypothermia era

• Published in: Nature reviews. Neurology Vol. 10; no. 4; pp. 190 - 203
• Main Authors: Greer, David M., Rosenthal, Eric S., Wu, Ona
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.04.2014; Nature Publishing Group
• Subjects: 692/699/375/1399; 692/699/75; 692/700/1421; 692/700/1750; Anesthesia; Animals; Biomarkers; Cardiac arrest; Cardiac patients; Care and treatment; Coma; Coma - etiology; Coma - pathology; Coma - therapy; Diagnosis; Drug withdrawal; Electroencephalography; Health aspects; Homeopathy; Humans; Hypothermia; Hypothermia, Induced - adverse effects; Hypoxia-Ischemia, Brain - complications; Hypoxia-Ischemia, Brain - pathology; Hypoxia-Ischemia, Brain - therapy; Materia medica and therapeutics; Medical imaging; Medical laboratory technology; Medical prognosis; Medical technology; Medicine & Public Health; Metabolism; Methods; Neuroimaging; Neurologic Examination; Neurology; Patients; Prognosis; review-article; Therapeutics; Treatment Outcome; United States > US
• ISSN: 1759-4758; 1759-4766
• DOI: 10.1038/nrneurol.2014.36

Key Points Therapeutic hypothermia (TH) influences the time course of neurological recovery after cardiac arrest, and the influence of added sedation is also of paramount importance Standard modalities for assessing prognosis might be influenced by the use of TH Promising tools for prognostication in the era of TH include certain blood biomarkers, brainstem reflexes, somatosensory evoked potentials, EEG reactivity, and neuroimaging findings Clinicians should use a multimodal approach to prognosticate for individual patients To improve generalizability of prognostic modalities, future studies should record, in a standardized fashion, the time before return of spontaneous circulation, the fraction of patients with out-of-hospital arrest, and other patient characteristics Standardization of terminology, procedures and outcome measures using common data elements in future prospective research investigations will improve comparisons—and potentially allow pooling of data—across studies Neurological prognostication in patients who remain in hypoxic–ischaemic coma after cardiac arrest has always been challenging, and has become even more so since the advent of therapeutic hypothermia (TH). In this Review, Greer et al . consider how neurological outcomes and prognostic indicators might be influenced by the use of TH, and discuss advances in neuroimaging and electrophysiology that are expected to aid neuroprognostication in this patient population. Neurological prognostication after cardiac arrest has always been challenging, and has become even more so since the advent of therapeutic hypothermia (TH) in the early 2000s. Studies in this field are prone to substantial biases—most importantly, the self-fulfilling prophecy of early withdrawal of life-sustaining therapies—and physicians must be aware of these limitations when evaluating individual patients. TH mandates sedation and prolongs drug metabolism, and delayed neuronal recovery is possible after cardiac arrest with or without hypothermia treatment; thus, the clinician must allow an adequate observation period to assess for delayed recovery. Exciting advances have been made in clinical evaluation, electrophysiology, chemical biomarkers and neuroimaging, providing insights into the underlying pathophysiological mechanisms of injury, as well as prognosis. Some clinical features, such as pupillary reactivity, continue to provide robust information about prognosis, and EEG patterns, such as reactivity and continuity, seem promising as prognostic indicators. Evoked potential information is likely to remain a reliable prognostic tool in TH-treated patients, whereas traditional serum biomarkers, such as neuron-specific enolase, may be less reliable. Advanced neuroimaging techniques, particularly those utilizing MRI, hold great promise for the future. Clinicians should continue to use all the available tools to provide accurate prognostic advice to patients after cardiac arrest.