A systematic review of the definitions of sedation for symptom relief noted a marked variation in the literature. A sedation definition was proposed to include two core factors:
- Presence of severe suffering refractory to standard palliative management.
- Use of sedative medications with the primary aim of relieving distress.
This review defined palliative sedation as "the use of sedative medications to relieve intolerable and refractory distress by the reduction in patient consciousness." The identified inconsistencies in the definition of sedation (i.e., primary versus secondary, light versus deep, and intermittent versus continuous sedation) should be subcategories of palliative sedation.
The use of palliative sedation for psychosocial and existential symptoms can be particularly controversial. Many ethical and clinical questions can arise for the clinician-questions that are more easily resolved in the case of palliative sedation for pain and physical symptoms.
For example, the ethical basis for the use of terminal sedation (double effect) is less clearly applicable in the case of psychiatric symptoms. Under this principle, the intended effect (relieving psychological suffering) would be considered allowable as long as any risks or negative effects (i.e., shortened survival) are unintended by the professional. Difficulty arises here because the principle discusses only the professional's intention, when it is the patient's intention that can be unclear and potentially problematic. Is the depressed patient who no longer wants to suffer depressive symptoms asking only for that relief, or is it also the patient's intent to ask the professional to shorten his or her life? Clinicians who feel uncomfortable in such situations might want to seek guidance from their ethics committees.
Other difficult questions can arise from the potentially negative value that is culturally assigned to "zoning out" as a lower form of coping. Should the anxious patient who no longer wants to face the anxiety associated with the end of life and desires sedation be encouraged to work through such issues? Or is it allowable for the anxiety of such patients to be handled with sedation? How many alternatives should be tried before anxiety is considered unacceptable? When dealing with such requests, professionals should consider their own cultural and religious biases and the cultural and/or religious backgrounds of patients and their families.
Few studies detail the use of terminal sedation for psychiatric symptoms. Four palliative care programs in Israel, South Africa, and Spain participated in one survey.[Level of evidence: III] One unique study has described the Japanese palliative care experience around these issues.[40,41][Level of evidence: II]
Noting the limitations of surveys and retrospective chart reviews,[42,43] researchers have completed prospective studies to determine the use of sedation for uncontrolled symptoms in terminally ill patients. Four palliative care programs with inpatient units in Israel, South Africa, and Spain reported that 97 out of 387 patients (25%) required sedation. In 59 of the 97 patients (60%), sedation was used for refractory delirium, with midazolam being the most common medication prescribed. A study of similar design in Canada reported that 80% of 150 patients developed delirium prior to death. Of the 150 patients, 9 required sedation for refractory delirium. A retrospective study at the MD Anderson Cancer Center in Houston included 1,207 patients admitted to the palliative care unit. Palliative sedation was used in 15% of admissions. The most common indications were delirium (82%) and dyspnea (6%). Sedation in these circumstances is often used on a temporary basis and was reversible in 23% of this group of patients.