Assessment of the efficacy of palliative sedation in advanced cancer patients by evaluating discomfort levels: a prospective, international, multicenter observational study

Background: Palliative sedation involves the intentional proportional lowering of the level of consciousness in patients with life-limiting disease who are experiencing refractory suffering. The efficacy of palliative sedation needs to be monitored to ensure patient comfort. The aim of this study was to evaluate the efficacy using discomfort levels combined with sedation/agitation levels.

Methods: In this prospective observational study, adult patients with advanced malignancies were recruited from hospice units, palliative care units, and hospital wards in five European countries. Health care professionals used proxy observations of discomfort levels (Discomfort Scale-Dementia of Alzheimer Type, range 0-27) and sedation/agitation levels (Richmond Agitation-Sedation Scale modified for palliative care inpatients), range - 5 to + 4) to evaluate the efficacy of palliative sedation.

Results: In 78 participants, discomfort levels were monitored during palliative sedation. The mean discomfort score before start was 9.4 points (95% CI 8.3-10.5), which showed a significant decrease of 6.0 points (95% CI 4.8-7.1) after start of sedation for the total sedation period. In the multivariable analysis, no significant factors influencing baseline discomfort levels were identified. The discomfort and depth of sedation scores were found to be positively correlated, with an r of 0.72 (95% CI 0.61-0.82). The internal consistency of the discomfort scale was good (0.83), but the "Noisy breathing" item was less informative of the total discomfort score.

Conclusions: The efficacy of palliative sedation can be evaluated by measuring discomfort levels combined with sedation/agitation levels. The measurement of discomfort levels might provide a more specific and detailed evaluation of adequate sedation.

Trial registration: This study is registered at ClinicalTrials.gov since January 22, 2021, registration number: NCT04719702.