SENSITIVITY, SPECIFICITY AND IMPACT ON PREOPERATIVE NEUROMONITORING OF SURGICAL STRATEGY BY SOMATOSENSORY-EVOKED POTENTIALS IN VASCULAR-SURGERY PERFORMED IN DEEP HYPOTHERMIC CIRCULATORY ARREST

Aim. - Median nerve somatosensory evoked potentials (SEP) monitoring p erformed in deep hypothermic circulatory arrest is useful in determini ng when brain cooling may sufficiently permit circulatory arrest, and to immediately indicate when brain injury occurs. The aim of this retr ospective study, including 58 patients, is to determine SEP sensitivit y, specificity and impact on the surgical strategy. Method - Sensitivi ty was determined on patients presenting nerv neurological complicatio ns. Specificity,uas measured on the patients without any new neurologi cal defect. The impact of intraoperative SEP on the surgical strategy was determined when the occurrence of SEP alterations had provoked a m odification of the surgical procedure. Results. - Five patients died i ntraoperatively due to non-neurological complications. Fourteen patien ts presented new neurological complications. SEP sensitivity reaches 6 4.3% when all the complications are included but increases to 100% in our series if late postoperative complications. paraplegia and tibial posterior nerve lesion are excluded because median nerve SEP are not a ble to detect such complications. SEP monitoring was uneventful in the 39 patients whose did not present neurological complication: thus SEP specificity is absolute in our series. SEP had an impact on the surgi cal procedure whenever neurological complications due to hemodynamic d isturbances occurred. Conclusion. - This retrospective study shows the interest of intraoperative SEP as an useful tool for promptly identif ying and preventing the neurological complication of hypothermic circu latory arrest. (C) 1998 Elsevier Paris.