Ethical validity of palliative sedation therapy: a multicenter, prospective, observational study conducted on specialized palliative care units in Japan.

Although palliative sedation therapy is often required in terminally ill cancer patients to achieve acceptable symptom relief, empirical data supporting the ethical validity of this approach are lacking. The primary aim of this study was to systematically investigate whether empirical evidence supports the ethical validity of sedation. This was a multicenter, prospective, observational study, which was conducted by 21 specialized palliative care units in Japan. One-hundred two consecutive adult cancer patients who received continuous deep sedation were enrolled. Continuous deep sedation was defined as the continuous use of sedative medications to relieve intolerable and refractory distress by achieving almost or complete unconsciousness until death. Prior to the study, we conceptualized the ethical validity of sedation from the viewpoints of physicians' intent, proportionality, and autonomy. Sedation was performed mainly with midazolam and phenobarbital. The initial doses of midazolam and phenobarbital were 1.5 mg/hour and 20 mg/hour, respectively. Main administration routes were continuous subcutaneous infusion and continuous intravenous infusion, and no rapid intravenous injection was reported. Of 59 patients who received artificial hydration or could intake adequate fluids/foods orally before sedation, 63% received artificial hydration therapy after sedation, and in the remaining patients, artificial hydration was withheld or withdrawn due to fluid retention symptoms and/or patient wishes. Of 66 patients who were able to verbally express themselves, 95% explicitly stated that symptoms were intolerable. The etiologies of the symptoms requiring sedation were primarily related to the progression of the underlying malignancy, such as cancer cachexia and organ failure, and standard palliative treatments had failed: steroids in 68% of patients with fatigue, opioids in 95% of patients with dyspnea, antisecretion medications in 75% of patients with bronchial secretion, antipsychotic medications in 74% of patients with delirium, and opioids in all patients with pain. On the basis of the Palliative Prognostic Index, 94% of the patients were predicted to die within 3 weeks. Before sedation, 67% of the patients expressed explicit wishes for sedation. In the remaining 34 patients, previous wishes for sedation were noted in 4 patients, and in the other 30 patients, the families were involved in the decision-making process. The chief reason for patient non-involvement in the decision making was cognitive impairment. These data indicate that palliative sedation therapy performed in specialized palliative care units in Japan generally followed the principles of double effect, proportionality, and autonomy.