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Literature review
We found three major (review) articles addressing the definitions of palliative sedation therapy. (Chater S, 1998; Morita T, 2002; Beel A, 2002).
In Chater’s study sedation was defined as “the intention of deliberately inducing and maintaining deep sleep for the relief of a) one or more intractable symptoms when all other possible interventions have failed, or b) profound anguish that is not amendable to spiritual, psychological, or other interventions, when the patient is perceived to be close to death”. This definition excludes sedation for delirium and “planned temporary sedation”, and only 40% of 53 palliative care specialists completely agreed with the definition. 60% did not agree for a variety of reasons: 1) sedation should exclude psychological distress as target symptoms; 2) “close to death” should be substituted with “imminently dying”; 3) sedation for relief from delirium should be included; 4) sedation should include intermittent sedation (reversal of sedation) and lighter sedation.
In Beel’s study, the authors identified 63 articles in their literature search. They found that 26 articles used the term “terminal sedation”, but only 9 articles defined the term. The authors used the term “palliative sedation therapy” with Chater’s definition.
In Morita’s systematic review designed to clarify the agreements and inconsistencies in the definitions of sedation, the authors identified 7 articles with clear definitions. The main findings were: 1) all studies included the use of sedative medications or the intention to reduce patient consciousness as an essential element of sedation; 2) all but one study explicitly described the primary aim of sedation as symptom palliation; 3) three definitions stated that target symptoms were severe; 4) four studies reported the refractory nature of the distress; 5) there were marked inconsistencies in the definitions of the degree of sedation, duration, pharmacological properties of medications used, target symptoms and target populations.
On the basis of the findings, the authors conclude that sedation includes two core factors:
1) the presence of severe suffering refractory to “standard” palliative management, and
2) the use of sedative medications with the primary aim of relieving this suffering.
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