Good question. I came across this on the Hacking Family.com website about cruising the world:
Medical: We have used International Medical Group in case of catastrophic illness. We pay about $400/child/year and about $1,300/adult, with a big deductible. It's only valid for people living outside the US. Canadian cruisers may not have to worry about this. All the medical care we've needed has been so inexpensive in the Third World that we've not even claimed on the insurance, but it does add up. Sue's back-work in Curacao came to $1,000 for X-rays, MRI, medications, and physical therapy. We've probably spent $1000/year on dental work here and there. When we went back to the US in the fall of 2003 we had insurance through Jon's work, but also paid out of pocket another couple thousand in medical care.