Healthcare Directives and Living Wills provide your Attorney-in-Fact with the type of care you wish to receive.
Healthcare Directives lay out for your Attorney-in-Fact what decisions you want made in regards to such things as feeding tubes, artificial respiration, oxygen etc.
A Living Will simply states that in the event you are in a terminal condition and not able to communicate, you do not want extraordinary measures used.
A HIPAA Release allows someone to have access to your healthcare information. This is often incorporated into your Healthcare Durable Power of Attorney.