Patient 7 was a 57-year-old male who was found at the base of a stairway. The patient neurologically deteriorated in the field, with decline in the GCS from 13 to 8, was intubated in the emergency department, and was admitted to the neuroscience intensive care unit. CT scans showed hemorrhagic contusions, subdural hematoma, and traumatic SAH. ICP, ptiO2, and rCBF probes, and intraparenchymal depth electrodes were placed in the right frontal lobe and continuous scalp DC/AC-EEG was monitored using Ag/AgCl-electrodes. Five SDs were observed on day 2, and elevated ICP at >40mmHg became intractable despite administration of muscle relaxants, pentobarbital, and 3% saline. Per discussions with family, a DNR-CC order was placed on day 5 and the patient was terminally extubated. Approximately 10 minutes thereafter, a slow, homogeneous DC shift was observed on intraparenchymal DC/AC-ECoG and scalp DC/AC-EEG electrodes in synchrony with the decline in oxygen saturation and PtiO2, a final ICP spike, and declining cerebral perfusion and respiratory arrest. Nonspreading depression was observed across intraparenchymal and scalp electrodes during the falling phase of ptiO2. Asystole for 20 seconds began 3 minutes later, only 13 seconds before the start of terminal SD (Fig ).
Patient 4, a 63-year-old man with previous myocardial infarction, hypertension, and diabetes mellitus, suffered from a CT-proven infarct of the complete right MCA territory. Decompressive hemicraniectomy was performed 37 hours after onset of the left-sided hemiparesis. On day 4, MRI additionally revealed infarcts in the vascular territories of the left MCA and right posterior inferior cerebellar artery as well as both cerebellar hemispheres. No SDs were recorded before the terminal one. A family discussion was held and a DNR-CC order was activated followed by terminal extubation on day 5. Figure B shows the nonspreading depression of activity during the falling phase of ptiO2. A very slow, homogeneous DC positivity started simultaneously with the drop in ptiO2. Superimposed on this DC positivity, the terminal SD then started at electrode 3.