What are some suggestions for change for first responders in post-incident injury that would reduce strain and stress?

Presumably, the question refers to injuries sustained by the first responder in the performance of his or her duties, and not the injuries sustained by the patient. First-responders, including local police, firefighters, ambulance crews and Emergency Medical Technicians (EMTs), are all employed in professions in which injury or death is a daily risk. All of these professions are inherently stressful, and, depending upon the scenario, involve varying levels of activity at the scene of the event. In other words, the event to which the first responder is responding could involve anything from a routine traffic accident to the detonation of a car or dirty bomb resulting in a large number of casualties. Obviously, the first example would involve minimal stress and little to no risk of injury to the first responder. The mass casualty scenario, in stark contrast, would involve considerable risk to the first responder, especially if secondary explosions occurred or the incident involved a live shooter armed with automatic or semi-automatic weaponry.
If a first responder is injured in the performance of his or her duties and, again, the injury occurs in the midst of a major event, such as a terrorist attack or fire, then the short-term risks are primarily physical and would be treated by physicians. The longer-term issues, depending upon the nature of the physical injuries (e.g. loss of limb or simple fracture) and of the incident in question, will affect the psychological state of the first responder to greater or lesser degrees.
For this answer, we will assume the injury is serious and sustained in a major incident. The level of risk associated with major incidents and the stress that is a regular part of the job of first responders requires regular counseling sessions to detect signs of post-traumatic stress disorder (PTSD), which can take months to materialize and even longer to become outwardly visible. PTSD is, however, potentially debilitating and, even at less extreme levels, can seriously impede the individual's ability to perform his or her responsibilities. The importance of mandatory psychological screening and occasional follow-ups cannot be overstated. Unlike physical injuries, mental impairment or conditions like depression or anxiety are, unfortunately, perceived as signs of weakness. The stigma associated with mental health problems has historically precluded their being adequately addressed. The conditions under which first responders function, however, demands a fundamental transformation in how issues like PTSD are perceived and handled.
If one recommendation could be offered, then, with respect to first responders dealing with post-incident injuries, it is the need for psychological counseling, even if the first responder insists that he or she does not need such care.