The ethical principle of patient autonomy mandates that the patient has control over what happens to him or her in the health care setting. Thus, the informed consent of a patient, either implicit or explicit, is necessary for all procedures, diagnostic tests, or treatments to be instituted. Informed consent and patient autonomy can occur only when the patient has the mental capacity to make decisions about his or her health care and is able to relay the decision to their provider. Decision-making capacity is not an all-or-nothing phenomenon. Decision-making capacity must be judged in each person based on the clinical circumstances, decision to be made, and consequences of the decision.<sup>2 Ethics in Emergency Medicine Tucson: Galen Press (1995). 

Cliquez ici pour aller à la section Références</sup> The decision to refuse sutures or an ankle splint has consequences different from the decision to refuse surgery for a ruptured spleen. Decision-making capacity can be impaired temporarily through the use of drugs or alcohol or by diseases or injuries, such as hypoxia, electrolyte imbalance, or a concussion. Some patients may have long-term impairment of their decision-making capacity based on chronic diseases or injuries, such as Alzheimer's dementia or a persistent vegetative state. In such circumstances, a surrogate decision maker, such as a relative or court-appointed guardian, is responsible for giving informed consent.

When evaluating decision-making capacity in individual cases, the emergency health care professional must judge whether the patient understands the options presented, understands the consequences of his or her decision, and is able to relate his or her decision to a stable framework of values.<sup>2 Ethics in Emergency Medicine Tucson: Galen Press (1995). 

Cliquez ici pour aller à la section Références</sup> Thus, the first option in fulfilling the obligation of patient autonomy and informed consent in emergency department (ED) patients is to evaluate the decision-making capacity of the patient based on the patient's mental status and on the nature and consequences of the decision. If the patient is unable to participate, a surrogate decision maker is sought. The patient or his or her surrogate should be involved in all decisions regarding diagnostic tests, procedures, and treatment. The patient's verbal communication at the time of the medical encounter takes precedence over any written advance directive that may be present in the medical record. An exception to the principle of informed consent is one that commonly occurs in EDs when there is a true medical emergency and no time to ask for consent. The patient who is in shock, respiratory failure, hypoglycemic coma, or cardiac arrest must receive emergent treatment. The general principle is to provide all treatment that a reasonable person would want if they were able to consent unless it is clear that the patient does not wish medical treatment. Advance directives can be a useful aid in these situations to guide clinicians in their decision making.

When the patient does not have the decision-making capacity to give informed consent or there is no time to ask the patient or his or her surrogate about treatment preferences, advance directives can be a useful adjunct in understanding the patient's values and choices. Advance directives express in written form what the patient's choices would have been if he or she had decision-making capacity. Advance directives include living wills, durable power of attorneys, and other written documents. Living wills are a type of advance directive that describes the patient's wishes if the patient's mental status deteriorates to a state in which he or she is unable to make a decision about health care or treatment. Living wills frequently direct health care providers to limit life-sustaining treatment. In the event that the patient has a terminal illness, the patient may not want artificial means of staying alive. The presence of a living will, however, does not mean that the patient wanted to limit their health care treatment. Some living wills ask that everything medically feasible be done to prolong the patient's life. Thus, each living will must be carefully reviewed to understand the patient's wishes.

The problem with living wills for emergency medical professionals is that many of the standard terms used are not well defined, and the emergency physician and EMT are faced with many uncertainties. For example, many living wills specify that patients do not want artificial means of support if they have a terminal condition. An elderly patient is admitted to the emergency department with an acute stroke and significant hemiparesis. Is that a terminal illness? A family member reports that a patient has a history of cancer—is he or she terminally ill? Are pneumonia, congestive heart failure, or renal failure terminal illnesses? The general assumption is these are all treatable diseases; however, if left untreated and sometimes even with prompt treatment, people may die of these diseases. Terms, therefore, may not be well defined. In medicine, we deal with probabilities but very few certainties. The prognosis for the patient with a stroke, myocardial infarction, or cardiac arrest may be unknown for a few days.

It is not uncommon to see patients with chronic and debilitating but not terminal diseases, such as stroke, arthritis, or Alzheimer's disease, present to the ED with acute reversible conditions, such as pneumonia. Should the patient with pneumonia be treated with antibiotics, pulmonary support, and intubation? Advance directives that express a wish to limit care focus on the fact that the patient would choose death rather than life with some treatment and diseases. The exact point that each person would choose death over a chance at continued life differs from person to person and may even differ in the same person from time to time, however. It is these details of emergency treatment and resuscitation that are not expressed in most living wills, yet it is precisely these details that are most important for emergency health care professionals. The time pressures for decisions regarding treatment are particularly acute for emergency health care providers. Gathering data and determining the extent of the patient's underlying disease, the patient's prognosis, and his or her wishes in the premorbid state therefore present a challenge for emergency physicians.

Another type of advance directive is the durable power of attorney. A durable power of attorney is a written document that gives the authority to another person, usually a spouse or relative, to make decisions regarding health care if the patient is incapacitated and unable to make decisions for himself or herself. Thus, the patient designates a surrogate decision maker who should participate in all significant treatment decisions and be kept up to date regarding the patient's health care. Durable power of attorney works best when the patient has discussed with the surrogate his or her values and beliefs as these would apply in making complex decisions regarding health care. If there is no durable power of attorney, surrogate decision makers may be sought based on state laws. There is usually a defined hierarchy regarding surrogate decision makers: spouses, adult children, siblings, and so forth. The surrogate decision maker must be acting in the best interest and according to the wishes and values of the patient. The durable power of attorney is a better form of advance directive than the living will because the surrogate can be educated about the nuances and options regarding each stage of treatment or nontreatment. For example, the patient with an acute stroke can be aggressively supported with intensive treatment for a period to determine which function would be regained. Further decisions on supportive care can be made after a few days, when the prognosis for return of function can be determined better. In another patient, the decisions may be made to treat pneumonia with antibiotics, oxygen, and supportive care, but not more aggressive treatments such as intubation and mechanical ventilation.

Advance directives should be respected by EMTs in the out-of-hospital setting. Prehospital advance directives are regulated through the state or local emergency medical services (EMS) authority. Optimally, there should be clear policies for out-of-hospital advance directives. In Arizona, for example, EMS providers recognize a standard orange prehospital advance directive form.<sup>4 Iserson K.V. A simplified prehospital advance directive law: Arizona's approach Ann Emerg Med 1993 ;  22 : 1703-1710  [cross-ref]

Cliquez ici pour aller à la section Références</sup> When this orange form is shown to the EMTs, they confirm the identity of the patient and, unless there is some unusual or suspicious circumstance, respect the directive. The directive usually requests limitation of care, such as refusal of resuscitation measures, including cardiac compression, endotracheal intubation, advanced airway management, and defibrillation. The use of a standard form, in which the patient, his or her primary care provider, and a witness sign the document, helps to avoid confusion. In addition, the form should contain a picture or other identifying data so that the EMTs are clear that it is the correct patient involved. The question usually arises as to why EMS were called for a patient who does not wish resuscitative procedures. There are multiple factors involved in calling EMS. The patient who does not wish to have resuscitation procedures performed may wish standard emergency treatments for reversible diseases such as pneumonia, asthma, or congestive heart failure. It is recommended that EMS providers respect standard advance directives; however, when there is confusion, disagreement among family, or any question regarding the legitimacy of an advance directive applying to patient's present condition, the recommendation is that EMTs err on the side of life and institute-appropriate treatment, including resuscitation.