Usefulness and diagnostic value of evoked potentials in surgical ICU patients with neurological deficits

Purpose: To analyse the diagnostic value of evoked potentials, 176 examinations in 71 sedated, ventilated ICU-patients who could only be examined neurologically on a very limited scale, were registered. We focussed on the evoked potentials, the results having prognostic relevance and beeing useful in the anatomical localisation of the pathological process. The Glasgow coma scale, neuroradiological findings and the data of the outcome status after hospital or rehabilitation discharge were therefore obtained. Results: We could show in distinct cases how evoked potentials could make a contribution to localise a pathogenic process. Failures in peripheral nerves, brachial plexus, myelin, brainstem and cerebrum were detected, respectively excluded. In the vast majority of cases, suspected symptoms were very precisely predicted. This was especially evident in patients suffering from head injury, hypoxia and spinal cord injury. We found that a good outcome can be expected even with high intracranial pressures if the repeatedly registered central conduction time stays normal. Conclusion: We conclude that non-invasive evoked potentials do enrich the bedside diagnostic pattern in sedated intensive-care unit patients. While neuroradiological methods only allow statements on morphological changing, evoked potentials demonstrate the functional status of the peripheral and central nervous system. This method is easy to learn and the cost involved is justified both financially and from the viewpoint of personnel expenditure.