in general all hikers, speleologists, trekker and rock-climbers should get medical insurance before undertaking any journey or activity - in fact, even basic medical treatment at rio's hospitals can quickly add up to thousands of dollars. 

furthermore, most hospitals will not provide any treatment past the initial emergency assistance without proper coverage or upfront payment.

companies such as medex, allianz, and travel guard are good starting point to start researching the best plans.