There are a number of problems I see with the way HEMS ops in the US are currently done, but I'll take bank robber Willy Sutton's advice and go "where the money is"... and that's CFIT.
Back when I was flying 'freighter' Be58s on night runs and a CE500 135, inadvertant IMC in a UH-60 or a BH-222 would have been no big deal. I would aviate, navigate and communicate. And the reason it was no big deal was I flew on the guages all the time. I was as comfortable IMC as I was on a pretty Spring day.
But instrument competence and comfort are perishable skills. Just because I could run three miles 2 years ago doesn't mean I could do that today. And just because I have a rusty old instrument ticket in my pocket doesn't mean I can fly on the guages today. And a 15 minute flight check with a set of Foggles each year just proves you can 'peek' good enough to smooze the check airman. If I want to stay in shape in both physical and instrument 'fitness' I have to 'exercise'.
I have the good fortune of flying for an operation that allows us to use our helicopter to maintain instrument currency in non-revenue flying. We also use the aircraft to get an IPC every year.
But I realize there are some bean counters that would have apoplexy at the thought of all that boring holes in the sky with no money coming in. But there are answers that I think would be cost effective. They would take the cooperation of the FAA and operators but they are doable.
First, the regs used to credit half your approaches and time in other category aircraft towards minimums. Why was this changed? Up until a couple of years ago I had a BE36 and it kept me sharp on instruments whether I was flying the Bonanza or our BK. Instrument flying is instrument flying. All my pilots are also fixed wing pukes. Half their currency requirements could be met semi-annually in a CE172 for a couple hundred bucks if the regs were changed back.
Second, give some credit for desktop simulators like the ASA On Top PCATD Flight Simulator. Yeah they cost about $3,000, but a group purchase could make them cheaper and they would be available all the time. Mandate that every pilot fly it every month. Allows you keep the procedural part of instrument flying down cold. Yeah, after flying the UH-60 full motion simulator I hate flying anything less too, but it keeps me 'sharp' and I like being sharp.
Third. Be absolutely frank with the hospital why they want to pay for the few extra hours you have to use the aircraft for instrument training. I presented the crash numbers to the bean counters in my organization and they now insist we do training and are happy to have us 'boring holes'. If they don't hear us checking in with dispatch on a 'training flight' for a while I get a polite inquiry about it...
We will never have a zero accident rate... but true instrument competence would go a long way to fixing this problem.