F106. Somatosensorial evoked potentials N20-N70 as a functional outcome for the medium and long-term after post-anoxy coma and coma after acute cerebral injury

Abstract

Coma, secondary to cardiorespiratory arrest or acute brain injury, leads to a high mortality-disability in the general population in patients aged 45–64 years. The somatosensory evoked potentials (SSEP) N20 and N70 are complementary neurophysiological tests that together with the electroencephalogram, the clinical examination, the biomarkers and the magnetic resonance to predict prognosis. N20 is well known for the short-term forecast, however the relevancy of the N70 potential is uncertain. The challenge is to know the functional recovery of the patient in the medium and long term crucial for the management and the expectations of the units of critics. Our goal is to analyze the usefulness of somatosensory evoked potentials (SSEP) N20-N70 as an early indicator of functional prognosis in the medium-long term and to assess its usefulness in patients after post-anoxic coma after cardiorespiratory arrest and in coma after Cerebral Injury Acute structural (CIAS) Observational, retrospective study performed in adult patients who had suffered post-anoxic coma (due to cardiorespiratory arrest) and after a CLC, admitted to the critical units of the General University Hospital of Albacete (January 2010 – December 2013). PESS study N20-N70 performed at 72 h of the event. Functional situation evaluated between 6 and 12 months later using the Modified Glasgow Scale considering: poor prognosis: 1-Death, 2-Persistent vegetative state and 3-Severe disability; good prognosis: 4-moderate disability and 5-good recovery. 120 patients were included, 60 patients in each group. In patients after postanoxic coma, the bilateral absence of N20 (36%) is an indicator of ominous vital prognosis (E 100%, PPV 100%) while its presence has no value to predict functional outcome (S 53%, NPV 50%). The presence of N70 (31%) is an indicator of good prognosis and its absence (68%) is a marker of poor prognosis (E 84%, PPV 92%, S92%, NPV 84%). On the other hand, in patients after CLC the bilateral absence N20 (41%) is an indicator of poor vital prognosis (S 54%, E 100%, PPV 100%, NPV 40%), bilateral absence of N70 (78%) is an indicator of poor prognosis while the bilateral presence of N70 (22%) is a marker of good prognosis (E 64%, S 91%, PPV 89%, NPV 69%). The results of our study demonstrate that both PESS N20-N70 are useful as early prognostic markers with high specificity (N20) and high sensitivity (N70). The realization of the potential N70 has additional value by increasing the prediction of good functional outcome in the medium-long term, especially in patients after post-atoxic coma.