Hospital volunteer work in Brazil?

I am looking to study Portuguese in Salvador and am looking to volunteer at a hospital or clinic in the area. I hear that they are in great need of volunteers and resources, yet many of these agencies charge an arm and a leg in order to talk to them for you. I was a medic for the military and have 6 years of experience in health care administration and management, I also have intermediate knowledge of Portuguese. Can anyone lead me in the right direction or know a direct contact?Thank you for your time!