As in many patients, vital signs don't tell the entire story. A patient can compensate for awhile, and normal V/S can fool some medical personnel. In the field, we usually use the pt's physical and mental presentation in a stroke (CVA) assessment. The pt's medical history can also play a large part in the assessment. In the field, the best we can usually do for a stroke pt is careful but rapid transport to a hospital. ALS care is mainly supportive (oxygen, cardiac monitor, and tko IV line). About 75% of strokes are from an infarction, or inadequate blood supply to a portion of the brain. This is usually due to an embolism or thrombus (blood vessel occlusion from atherosclerosis).