When patients are lacking in decisional capacity, we depend on others to make decisions for them. This surrogate decision maker may be formally appointed by the patient (e.g. through durable power of attorney or DPOA), may be a legal next of kin (LNOK) as defined by the state, or (in absence of the former options) a guardian appointed by the state.
Surrogate decision makers are expected to make decisions for the patient using a (1) substituted judgment standard (i.e. deciding as the patient would under the circumstances, e.g. did the patient ever talk about not wanting to be on a ventilator?) or (2) best interest standard (i.e. deciding according to what seems to be in the best interests of the patient based on what we know about the patient, e.g. does an intervention provide reasonable benefit and minimal risk based on the patient’s circumstances?).