Clinical Aspects of Palliative Sedation in Prospective Studies. A Systematic Review

Near the end of life when patients experience refractory symptoms, palliative sedation may be considered as a last treatment. Clinical guidelines have been developed, but they are mainly based on expert opinion or retrospective chart reviews. Therefore, evidence for the clinical aspects of palliative sedation is needed.

To explore clinical aspects of palliative sedation in recent prospective studies.

Systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered at PROSPERO. PubMed, CINAHL, Cochrane, MEDLINE, and EMBASE were searched (January 2014-December 2019), combining sedation, palliative care, and prospective. Article quality was assessed.

Ten prospective articles were included, involving predominantly patients with cancer. Most frequently reported refractory symptoms were delirium (41%-83%), pain (25%-65%), and dyspnea (16%-59%). In some articles, psychological and existential distress were mentioned (16%-59%). Only a few articles specified the tools used to assess symptoms. Level of sedation assessment tools were the Richmond Agitation Sedation Scale, Ramsay Sedation Scale, Glasgow Coma Scale, and Bispectral Index monitoring. The palliative sedation practice shows an underlying need for proportionality in relation to symptom intensity. Midazolam was the main sedative used. Other reported medications were phenobarbital, promethazine, and anesthetic medication-propofol. The only study that reported level of patient's discomfort as a palliative sedation outcome showed a decrease in patient discomfort.

Assessment of refractory symptoms should include physical evaluation with standardized tools applied and interviews for psychological and existential evaluation by expert clinicians working in teams. Future research needs to evaluate the effectiveness of palliative sedation for refractory symptom relief.