Here in Oz I can recall at least three accidents resulting in around ten fatalities in which the common thread was:
a lack of "risk vs gain" philosophy,
wrong helicopter,
wrong crew qualifications, and
bad weather or lack of visual cues.
HEMS is not war - as a PIC you just have to learn to say NO - there is always another way.
Australian HEMS has learnt the lessons - the cowboy operators have largely been weeded out - the HEMS now have proper equipment - twin SPIFR - NVG - CRM training - support from non aviation management should a mission be declined ie your job is not at risk.
I'm afraid from the outside looking in it APPEARS that US HEMS has a press on at all costs attitude.
Mind you an assessment of accidents per hours flown may provide interesting reading for comparison purposes.
GAGS
E86