Efficacy of two types of palliative sedation therapy defined using intervention protocols: proportional vs. deep sedation

Kengo Imai, Tatsuya Morita, Naosuke Yokomichi, Masanori Mori, Akemi Shirado Naito, Hiroaki Tsukuura, Toshihiro Yamauchi, Takashi Kawaguchi, Kaori Fukuta, Satoshi Inoue

This study investigated the effect of two types of palliative sedation defined using intervention protocols: proportional and deep sedation. We retrospectively analyzed prospectively recorded data of consecutive cancer patients who received the continuous infusion of midazolam in a palliative care unit. Attending physicians chose the sedation protocol based on each patient's wish, symptom severity, prognosis, and refractoriness of suffering. The primary endpoint was a treatment goal achievement at 4 h: in proportional sedation, the achievement of symptom relief (Support Team Assessment Schedule (STAS) ≤ 1) and absence of agitation (modified Richmond Agitation-Sedation Scale (RASS) ≤ 0) and in deep sedation, the achievement of deep sedation (RASS ≤ - 4). Secondary endpoints included mean scores of STAS and RASS, deep sedation as a result, and adverse events. Among 398 patients who died during the period, 32 received proportional and 18 received deep sedation. The treatment goal achievement rate was 68.8% (22/32, 95% confidence interval 52.7-84.9) in the proportional sedation group vs. 83.3% (15/18, 66.1-100) in the deep sedation group. STAS decreased from 3.8 to 0.8 with proportional sedation at 4 h vs. 3.7 to 0.3 with deep sedation; RASS decreased from + 1.2 to - 1.7 vs. + 1.4 to - 3.7, respectively. Deep sedation was needed as a result in 31.3% (10/32) of the proportional sedation group. No fatal events that were considered as probably or definitely related to the intervention occurred. The two types of intervention protocol well reflected the treatment intention and expected outcomes. Further, large-scale cohort studies are promising.