Amplitudes of SSEP and outcome in cardiac arrest survivors

Abstract

The prognostic value of SSEPs extends beyond an absent/present dichotomy. Absent and very low amplitude SSEPs appear to be highly predictive of poor outcome after cardiac arrest. Prospective external validation of the lower threshold found in our study is necessary. SSEP recordings should not be used for prognostication if noise could mask potentials with critically low amplitudes. High SSEP amplitudes argue against severe hypoxic encephalopathy.

Multimodel quantitative analysis of somatosensory evoked potentials after cardiac arrest with graded hypothermia

“…SSEP amplitude has been shown to be related to functional outcome [16]. Here we demonstrate that N10 amplitude is correlated with both N10 latency and qSSEP-PSA during the early recovery from severe brain injury with graded hypothermia.…”

“…Only one human study has examined the relationship between SSEP amplitude and outcome, suggesting a threshold amplitude voltage to distinguish good and bad outcomes [16]. However, the study does not use specific response peaks in the evaluation of amplitude.…”

“…The present study demonstrated better recovery of N10 amplitude in animals treated with lower temperature grades and with good functional outcome and that N10 latency was overall longer than baseline in animals with deeper hypothermia and good outcome. Although our previous study has shown that hypothermia increases N10 amplitude and latency compared to normothermic groups in an uninjured rat model [17], it has been suggested that the effect of mild hypothermia (33°C) does not have a significant effect on the relationship between SSEP amplitude and outcome in a human study [16]. …”

Early-SEPs’ amplitude reduction is reliable for poor-outcome prediction after cardiac arrest?

“…When evaluating the cortical responses of both hemispheres, the SEP amplitude was defined as the highest amplitude of N20/P25, as indicated by Endisch et al 14 The outcome was dichotomized between recovery of consciousness (GOS score [3][4][5] and no recovery of consciousness (GOS score 1-2). The mean values for SEP amplitude for different outcome groups and different EEG patterns were analysed by ANOVA followed by post-hoc analysis.…”

Clinical neurophysiology for neurological prognostication of comatose patients after cardiac arrest

“…As a matter of fact, the bilateral absence of N20 highly correlates with poor outcome, after (FPR 0.5%, 95%CI: 0–2% (Bouwes et al, 2012, Leithner et al, 2010, Oddo and Rossetti, 2014, Samaniego et al, 2011a, Hofmeijer et al, 2015)), but also during TTM (FPR 0%, 95%CI: 0–2% (Sandroni et al, 2014, Leithner et al, 2010)). It has recently been suggested that quantitative assessment of the N20 amplitude may offer additional prognostic information (Endisch et al, 2015), however this study needs to be replicated before this item can be used routinely. While early-latency SSEP accuracy is extremely high for prediction of poor prognosis, they have no role to forecast favourable outcome, with positive predictive values of a present N20 ranging between 40% (29–50%) (Hofmeijer et al, 2015) to 58% (95%CI: 49–68%) (Oddo and Rossetti, 2014).…”