Pain-related Somato Sensory Evoked Potentials: a potential new tool to improve the prognostic prediction of coma after cardiac arrest

Abstract

IntroductionEarly prediction of a good outcome in comatose patients after cardiac arrest still remains an unsolved problem. The main aim of the present study was to examine the accuracy of middle-latency SSEP triggered by a painful electrical stimulation on median nerves to predict a favorable outcome.MethodsNo- and low-flow times, pupillary reflex, Glasgow motor score and biochemical data were evaluated at ICU admission. The following were considered within 72 h of cardiac arrest: highest creatinine value, hyperthermia occurrence, EEG, SSEP at low- (10 mA) and high-intensity (50 mA) stimulation, and blood pressure reactivity to 50 mA. Intensive care treatments were also considered. Data were compared to survival, consciousness recovery and 6-month CPC (Cerebral Performance Category).ResultsPupillary reflex and EEG were statistically significant in predicting survival; the absence of blood pressure reactivity seems to predict brain death within 7 days of cardiac arrest. Middle- and short-latency SSEP were statistically significant in predicting consciousness recovery, and middle-latency SSEP was statistically significant in predicting 6-month CPC outcome. The prognostic capability of 50 mA middle-latency-SSEP was demonstrated to occur earlier than that of EEG reactivity.ConclusionsNeurophysiological evaluation constitutes the key to early information about the neurological prognostication of postanoxic coma. In particular, the presence of 50 mA middle-latency SSEP seems to be an early and reliable predictor of good neurological outcome, and its absence constitutes a marker of poor prognosis. Moreover, the absence 50 mA blood pressure reactivity seems to identify patients evolving towards the brain death.

Neurological prognostication of outcome in patients in coma after cardiac arrest

“…63 A recent study suggests that the painful modality may be informative of consciousness recovery (PPV 100%, 95% CI 87-100%) even before EEG reactivity. 64…”

Somatosensory and auditory deviance detection for outcome prediction during postanoxic coma

“…In particular the absence of cortical SSEP responses is highly informative of poor outcome . Other studies have proposed SSEP amplitude for predicting good outcome either at early or middle latencies in the response window . The optimal use of the SSEP for predicting good outcome in patients especially in modern clinical application of TTM targeting 33 or 36°C is currently under exploration.…”

Cerebral Pathophysiology in Extracorporeal Membrane Oxygenation: Pitfalls in Daily Clinical Management

“…Somatosensory evoked potentials (SSEP) provide information about cortical signals in the somatosensory cortex after a peripheral stimulus. This can be helpful to prognosticate cerebral injury if the cortical potentials are absent [ 96 ]. The optic nerve sheath diameter (ONSD) can be used at bedside to detect elevated ICP [ 97 ].…”