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 5 was a 47-year-old male occupant of a car struck by a train with reported field Glasgow Coma Scale (GCS) = 3. The patient was intubated for airway protection and arrived at the trauma center with presentation GCS = 3T. Bilateral chest tubes were placed for traumatic pneumothoraces. Once stabilized, the patient had a postresuscitation GCS = 1T3. CT of the head demonstrated skull vault fractures, diffuse traumatic SAH, subdural hematoma, and diffuse petechial shear injuries. He was admitted to neurocritical care, and an ICP monitor was placed with elevated ICP noted. A family discussion was held on day 2, a DNR-CC order was activated, and the patient was terminally extubated. Similar to Patients 2 and 4, nonspreading depression occurred while ptiO2 showed the final drop. The terminal SD started 73 seconds after nonspreading depression had rendered the ECoG isoelectric (Fig A, B).