Fig. 1. Systolic (SBP), diastolic (DBP), and mean arterial pressures (MAP) in the immediate postoperative period in relation to postoperative events and intravenous vasopressor infusion doses are shown. After arrival to the surgical intensive care unit at 11:45 am, the patient became hypotensive at 12:30 pm (event A), and developed paraplegia at 12:45 pm. A lumbar cerebrospinal fluid drain was inserted and functioning at 1:25 pm. Bilateral lower extremity motor strength and sensation returned at 2:00 pm (event B) and neurologic examination demonstrated normal symmetrical motor strength and sensation in the lower extremities at 7:30 pm (event C). The hemoglobin concentration was 13.8 g/dl at 1:15 pm.