Here's some info from the military side:

http://www.usuhs.mil/uao/Release03-03-05.pdf

An excerpt:

“Hemostatic agents without this exothermic property will be available in the future and should be evaluated as a potential replacement. Until that time, used carefully in this well-defined population who are still bleeding despite all standard current therapy, it seems that the benefit of saving a life outweighs the risk .”

"The panel also reinforced the FDA’s recommendation for use by reporting that given tissue damage from this exothermic reaction may be a risk, this agent should only be used for lifethreatening hemorrhaging."