Human life is good and to be protected.
All medical decisions ought to reflect this core belief. Yet black-and-white answers to our questions about end-of-life issues are not always possible, and it can be very difficult to know how to make medical decisions.
Each and every human person is distinct and unrepeatable, and each medical situation may be unique. In each set of circumstances we need to judge whether a given treatment will provide real benefit to the patient, without causing harm or other burdens that are out of proportion to the good being done. (From the USCCB)