Arthur is a very healthy and active 73-year-old. He was physically fit, running or biking daily. While windsurfing, Arthur fell into the water and the sail hit his head. The Lifeguard dragged him to shore. When the paramedics arrived at the scene, they found him lying in a supine position, unable to move any extremities and complaining of neck pain. He was awake, alert, and orientated to his current location, the date and day of the week, and the details of his windsurfing incident. His responses to questioning were appropriate. His pupils were equal and reactive to light. He showed no other signs of injury. His vital signs revealed a blood pressure of 108/69, heart rate of 86 beats per minute, respirations of 24 per minute and shallow. A cervical collar was applied; he was placed on a backboard and transported to the nearest hospital in Cuba. In the Emergency Department Arthur was able to shrug his shoulders slightly and barely move his biceps. He was able to feel his face, neck and shoulders but his body felt numb. His arms and legs were flaccid despite attempts to move them. His vital signs were taken again and showed a blood pressure of 91/46, heart rate of 54, respirations were 26 and shallow. His oral temperature was 38.3 degrees Celsius. His color was dusky, and his skin was warm and dry to touch. X-rays taken on arrival revealed a spinal fracture. A chest x-ray showed a decreased lung expansion upon inhalation. Blood tests were normal, with the exception of a respiratory acidosis. The Emergency Department Physician stabilized his neck and transferred Arthur to the Intensive Care Unit. He was intubated and sedated for several days. Emily wanted arrangements for Arthur to be transferred back to Toronto, Ontario where they lived as soon as possible. After four days and upon arrival to the Toronto hospital, a physical exam was done. The Neurosurgeons noted normal vital signs with no change in Arthur's arm strength or sensation. He had marked spasms and exaggerated stretch reflexes of his extremities. He had an indwelling urinary catheter and was incontinent of stool.
Why did Arthur's heart rate and blood pressure fall in this time of emergency?