Unresponsive wakefulness or coma after cardiac arrest-A long-term follow-up study

Area of Science:

• Neuroscience
• Critical Care Medicine
• Neurology

Background:

• Cardiac arrest (CA) survivors discharged from the intensive care unit (ICU) often remain in unresponsive wakefulness syndrome (UWS) or coma.
• Investigating early prognostic markers is crucial for predicting neurological recovery in these patients.

Observation:

• A prospective study followed 89 cardiac arrest patients discharged in UWS or coma.
• Data collected included clinical course, Coma Recovery Scale-Revised (CRS-R) scores, somatosensory evoked potentials (SSEP), electroencephalography (EEG), gray-white matter ratio (GWR) from CT, and neuron-specific enolase (NSE) levels.

Findings:

• Neurological improvement beyond UWS was observed in only 2 out of 63 patients.
• Established poor outcome markers (high NSE, low SSEP amplitude, malignant EEG, low GWR) were present in a significant proportion of patients.
• Normal ranges for NSE, SSEP, and reactive EEG were found in a small percentage of non-improving patients.

Implications:

• Neurological recovery is infrequent in CA patients with prolonged ICU stays and UWS.
• Early prognostic markers (SSEP, EEG, NSE) may help identify patients with severe hypoxic-ischemic encephalopathy (HIE) but have moderate sensitivity.
• Status epilepticus requiring deep sedation could contribute to delayed awakening.