It's important to note that evidence preservation will be much more important for a wreck with major injuries or fatalities than a typical fender bender, and common sense must be employed. If you are first on scene of a minor fender bender that's blocking the roadway, there won't be some crazy investigation. The cars should be removed from the roadway as quickly as practical and evidence preservation will be of minimal importance.
We march in, pull out tools, kick debris out of the way, cut the cars apart and in general destroy evidence from the moment we arrive. On your approach to a TC, you should be assessing for all these hazards anyway, but there are few other things that all too often fall through the cracks.
As you approach the scene and select a safe and appropriate place to park your apparatus, be sure to avoid driving or parking over evidence. This includes skidmarks, glass, debris puddles of fluid, damaged sections of roadway and anything else that wasn't there before the collision occurred. If law enforcement is already on scene, park as directed -- the officers on scene probably won't direct you to park in an area that destroys evidence or will impede their investigation. If everyone is on the same page regarding blocking lanes, it'll be that much better.
As you approach the vehicle(s), in addition to continually assessing for hazards and scene safety issues, displace as little evidence as you can. Don't kick debris out of your way, and if you do move evidence, be sure that law enforcement knows how you've altered the scene. If it's feasible, allow law enforcement a moment to see the vehicle(s) in it's final rest position before beginning extrication. More and more agencies are implementing policies forbidding the taking of pictures on scene, and if you don't have a policy forbidding it and you do decide to take pictures, be aware that your pictures could end up being subpoenaed by law enforcement. If there is any doubt about when a collision occurred, touch the hood of the car and see if it's warm. This can help you estimate when the TC happened, and that knowledge could come in handy later. If the engine block is cold, it's probable that the wreck happened some time ago and has only recently been reported. This is good to know, particularly in late night DUI collisions with minor injuries, as the drunk driver may have delayed reporting the accident in the hopes of sobering up before the cavalry arrives.
As you evaluate the vehicle and patient, assess for injuries and evaluate the mechanism of injury, bear in mind that the indicators we use for these purposes frequently help law enforcement investigate the scene. That beer can jumps out as evidence, but what about the prescription bottle?
As you begin the process of extricating the patient, the scene can change quickly and dramatically, especially in a complex rescue situation. Evidence can be altered and destroyed, and care should be taken, when practical, to minimize this.
Once the patient is extricated, law enforcement will frequently try to obtain a statement from them. If the patient's condition allows for it, it's helpful to allow the officer to obtain the statement while still at the scene. Bear in mind that the patient's injuries themselves may be evidence (ie, forehead trauma consistent with striking the windshield, seatbelt abrasions, etc) that will contradict a patient's statement. This frequently happens with DUI/DWI collisions or when a driver is unlicensed. They lie about where they were in the vehicle at the time of the collision. If your physical findings contradict the patient's statements, it's a good idea to OBJECTIVELY document that. Slurred speech, odor of alcoholic beverages (not the odor of alcohol itself -- it's odorless), horizontal gaze nystagmus (HGN) and other physical signs of intoxication are important for both you and law enforcement. A blood sugar will be important to obtain as well, as drunks can play the diabetic card and diabetics can appear to be drunk. Pupillary response can be an indicator of both head trauma and narcotic use, so be sure to document those findings as well.
If your jurisdiction and agency protocols and procedures allow for an evidence blood draw, follow those guidelines. If not, or the officer doesn't have the blood kit, then don't do it. There's not a lot that's more frustrating than watching a drunk go free because of improperly obtained evidence, and you don't want your blood draw to be the weak leak in the chain of evidence. Using improper technique or standard blood tubes is a great way for a savvy defense attorney to get a drunk off the hook. The rules of evidence require that the chain of custody not be broken, and standard blood tubes don't typically meet the criteria for a legal blood draw.
Also be aware that doing a favor for a cop buddy can turn around and bite you down the road if your agency or protocols forbid the blood draw. If the case goes to trial and you get subpoenaed to testify in the case, you will probably find yourself in hot water for violating the rules. Getting drunks off the road is great, but not at the risk of a medic losing their job.
Another issue to consider is vehicle vs pedestrian incidents. When this happens, someone screwed up, and the potential for serious injury is very high. Be especially alert to anything that immediately suggests fault, especially if the evidence contradicts the statements by the involved parties. If your pedestrian patient is clutching a paper bag with booze in it or has a death grip on their cell phone, that suggests that inattention to their surroundings could have contributed to the incident. If the pedestrian was in a crosswalk in good lighting conditions, that suggests that the driver may have been the inattentive one. If the ped was wearing dark clothing and crossing the street at midnight in the middle of the block, they'd be hard to see. If the EMS crew removes the patient's clothing and disposes of the clothes upon arrival at the hospital, they've destroyed evidence that could be pivotal in determining fault.
While it's not EMS's responsibility to investigate the scene or determine cause from a legal perspective, situational awareness and proper documentation of the scene, circumstances and patient conditions can be very helpful to the investigating officer and agency. Evidence can be smaller than paint chips & glass fragments and larger than a Mack truck, so it's important to be aware of its presence and importance. Evidence can be cars, people, clothes, vehicle contents, personal effects and just about anything else, so be careful what you do out there. Pay attention to your surroundings, and minimize your negative impact on the crime scene.
Again, this is not meant to be all inclusive, but it's a good start. Stay tuned for the next crime scene...
