My parents were in Mexico when my dad had a blood clot in his leg. None of the hospitals will see you without payment up front. Luckily, my parents had large credit card cash withdrawal amounts available and was able to get the $3000 that my mom needed to get my dad into the hospital at the first place (resort town south of Cancun) and then another $5000 for the hospital in Cancun. Cash only. No cash, no admittance. My dad was flown out of Cancun to Miami on a private medical transport along with two flight nurses and my mom, all arranged by their medical insurance company. He then spent three weeks in a Miami hospital trying to get the clot dissolved. He eventually had to fly home first class (insurance company insisted) and had surgery once he got home. My mom stayed in a hotel in Miami for the three weeks he was there. Once in the US they did not have to pay upfront. Their insurance (UPMC, I think or UMPC?) paid all costs including the Mexico hospitals, air transport, the 1st class plane ticket and most of my mom's hotel bill with the exception of $100. They never saw any of the bills as the insurance company took care of paying all involved and refunded my parents their OOP costs.
But, the hospitals in Mexico would not have had a problem letting my dad die if they didn't have the money to be admitted. Please make sure you have a credit card that allows cash withdrawals so you can get services in a foreign country when you travel.
