I'm not sure how well this will translate into the civilian sector, but we ran into this a fair amount in the deployed setting when I was serving as an Army RN. I always noticed after very difficult cases or mass casualty events, I ran into a lot of my peers at the gym after shift. It helped me to work off some of the tension, anger, and other bottled up emotions that come with handling this type of trauma to funnel it into something productive and physical like a workout. Physical activity is also beneficial for your body and your mind and it helps to tire you out, giving you a better chance of getting that much needed sleep afterwards. Some hit the weights, some cardio, some even would give a go at a punching bag.
Debriefing, which I'm sure all emergency and critical care folks are quite familiar with, is also acutely necessary. It gives everyone involved a chance to review the situation, discuss, and even make some sense of what they experienced. It also helps to prepare for the next time you may have to intervene in these situations.
Coming from a psych perspective, I can't say enough how important it is to have healthy coping skills. Whether that's music, art, making bird houses, or even taking pole dancer lessons. Something that you enjoy. People you can talk and vent to. In these type of situations, I strongly discourage using substances to cope. From both military and civilian backgrounds, I've seen many take this path and it always seems to end poorly. If you notice that you're struggling after an experience, please don't be afraid to reach out for assistance. It's far better to make an appointment, be seen and get treated, rather than let things spiral out of control and potentially threaten your career and life. Remember there are a lot of us who have been through the trenches with you. We're here to help if you need us.