Emerging trends in monitoring the comatose brain

Mihai Moldovan (1,2), 1) Division of Physiology and Fundamental Neuroscience, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; 2) Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark

SNN 2014 Conference
October 23 - October 25, Bucharest

Abstract published in Fiziologia - Physiology, 2014, Supp 2


During comatose states occurring after brain injury (i.e following a hypoxic/ischemic insult) but also during medically induced coma (i.e for surgical general anesthesia, treatment of status epilepticus or neuroprotection after traumatic brain injury) the patients lose their awareness and become unresponsive to external stimuli. Nevertheless, their brain EEG reactivity to various somatosensory stimuli is preserved. Evoked potential measurements, while very useful in assessing primarily the integrity of the sub-cortical pathway, offer limited information about the cortical function itself, especially during “deep” comatose states characterized by discontinuous “burst-suppression” (BS) EEG. The current dogma is that when the bursting occurrence can be altered by external stimuli, then this may be an indication of a better prognostic. Nevertheless, even when some stimuli can appear to evoke bursts (i.e clapping), at stimulus repetition, other seem to fail. This makes the investigation of BS reactivity appear an unreliable prognostic marker. As there are no standardized protocols for assessment of BS reactivity, its clinical value remains poorly understood. This presentation reviews our current work at the ComaEEG.RO on standardizing measures of BS reactivity, using patient investigations and experimental studies in rodents. Monitoring the “suppressed” brain integrity may become increasingly important with increasing use of therapeutic general anesthesia and hypothermia during the coming years.