Because he's a paramedic, my dad owns a police scanner. About five minutes after we heard the bike go by, it picked up a medical dispatch: a motorcycle crash at the intersection where our street dead-ends against a perpendicular road. Even as we hurried out to the front lawn we could hear police and fire sirens in the distance. My dad grabbed his medical kit and drove his truck down the half-block to the accident scene. He had to explain to some anxious bystanders - and the police, when they arrived - who he was and what his qualifications were.
Apparently, the dirt bike rider had gone straight down the street, and had also tried to go straight at the T-intersection. Witnesses said that his bike had no headlights. His bike had rammed into the sidewalk and he had been ejected from it and into the front yard of a house. Judging by the scene, he had flown over a car parked in the driveway, banging his legs up and denting the car in the process, flown over a boat trailer and put his head through the fence separating the back and front yards.
When my dad arrived, he assessed all of this while putting on gloves and goggles. The first thing he looked at was the patient's ABCs: airway, breathing, circulation. The first thing he noticed was that the man's chest was not moving, most likely because his head was bent severely to the side, almost resting on his shoulder. He did have a pulse, but he was unconscious. Carefully, my dad grabbed him by the shoulder and the pants and moved him just far enough away from the fence to straighten out his neck. He did a jaw thrust to open up the airway, and the patient started breathing on his own. My dad held his jaw open until the fire engine arrived just a few minutes later. During this time he distinctly smelled alcohol on the man's breath.
When the firefighter EMTs - men my dad knew from work - appeared, he reported to them on the patient's condition: breathing, unconscious, but with a pulse. Other, non-life-threatening injuries became apparent. The bike rider had a badly mangled left leg where it had impacted with the parked car: his ankle and tibia were broken and his knee was ripped open to the bone. The leg was bleeding, but not badly, so the EMTs reevaluated the man's ABCs. He was still breathing on his own, although there were some gurgling sounds in his throat -- probably blood. They began putting him on a back board as the ambulance arrived, and together they packaged him for transport. This included immobilizing his head with a c-collar and pinning him to the board with what's known as 'spider straps'.
About this time the patient, while still unconscious, started being combative, trying to bat away the nasal pharyngeal airway and re-breather mask. This kind of movement is known as 'purposeful movement', and it's a good sign. He also tried to knock away the hands of the paramedics as they did a thorough head to toe exam. They found several good indicators: there was no apparent injury to his chest or abdomen, and his pupils responded to light. However, he did have a serious deformity to the right side of his skull. He also had a 'right-sided gaze', which can be a sign of brain damage. As the patient was loaded into the ambulance, it was noted that the man was only being combative with his right arm and leg; his left side was not moving.
When my dad had arrived, he had notified the police to call for a helicopter. It landed in a nearby park as the patient was loaded into the ambulance. By this time, his leg had been wrapped in gauze and bandaged, although there was dirt everywhere and the wound was no doubt filthy. He was also being given a fairly high - 90% - concentration of oxygen.
At this point, we don't know the man's fate. Because of privacy laws these days, my dad may not be able to find out. He does think the major problem will be the head injury, that he might perhaps have a subdermal or epidermal hematoma. However, if my dad hadn't been there to perform first aid and get the patient breathing again, he likely would have had a heart attack and coded before the EMTs arrived.