I am writing a scene where my heroine gets shot in the scuffle with the bad guy. If she’s shot in the brachial artery in her left arm, is it conceivable that she’d pass out and bleed a lot? Her firefighter hero is there and immediately rips off his shirt and balls it up to stop/slow the bleeding. He then uses a strip of fabric from another shirt to tie around that and then carries her to a waiting police car to get her to the hospital—in this case, an ER clinic.
How much danger is there of bleeding out? Is the pressure wrap enough? Can she survive? What would be the treatment? Surgery, I assume, and blood transfusions. Would she remain unconscious and for how long?
Yes, it is conceivable that she would pass out and bleed a lot. The brachial artery will bleed briskly and quickly and without direct intervention she could bleed to death in a matter of minutes (3-6 min). I think both methods to control the bleeding need to happen quickly. The firefighter can direct a bystander to apply direct pressure while he fashions the tourniquet as he will have more experience. The tourniquet should be applied above the level of bleeding. After those two measures, I would have the firefighter continue direct pressure at the sight with a compression dressing. This will be better than continuing to hold direct pressure.
To your specific questions:
Without intervention, this character is in great danger of bleeding out. With immediate intervention, she should be all right.
I would do both the tourniquet and the pressure dressing.
Initial treatment by EMS would be to establish IV access very quickly and start supporting the fluid loss with IV fluids. A set of vital signs. Possibly oxygen if her heart rate is really elevated, her oxygen level is low, or she’s exhibiting any kind of distress.
Since she is being transported by a police car, these would then become the initial steps performed in the ER.
Upon arrival to the ER, labs will be drawn to check her blood counts. If low, then blood transfusion would be warranted. Repairing a severed artery will require surgery.
Whether or not the character goes unconscious depends on a lot of factors. A person can just pass out from looking at blood and the stress of being shot in addition to blood loss. If a person passes out from blood loss, they should regain consciousness as soon as their blood pressure is normalized either with IV fluids and/or blood transfusions.
You mention an “ER clinic”. I’m not quite sure what you mean by this, but a free standing ER, urgent care, or an “emergency” room outside a major hospital can have limitations in the type of care they can deliver. So, if it’s such a situation, the patient would need to be transferred to a larger hospital (for surgery, admission, etc).
Best of luck with this story!