Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. This randomized controlled trial demonstrated a reduction in the incidence of the death rattle upon dying patients receiving prophylactic subcutaneous scopolamine butylbromide (an anticholinergic) compared to placebo.

Evidence Rating Level: 1 (Excellent)

Study Rundown:

The death rattle, caused by mucus in the upper respiratory tract causing noisy breathing, is common in dying patients and often cause distress to patients’ loved ones. Current management consists of non-pharmacological and pharmacological measures. When non-pharmacological interventions fail, anticholinergics drugs are used to reduce the death rattle.Anticholinergics decrease mucus production but do not affect mucus that is currently present; therefore, once the death rattle is apparent, these drugs may not be effective. The SILENCE trial is a randomized, double-blind, placebo-controlled, multicentre clinical trial that investigated whether prophylactic scopolamine butylbromide (anticholinergic drug) could reduce the death rattle. This study was conducted from April 10, 2017, until December 31, 2019. Eligible patients (162) were randomized 1:1 to receive 20 mg scopolamine butylbromide or placebo subcutaneously four times daily. The primary endpoint was the presence of a grade 2 or greater death rattle measured at two consecutive time points at an interval of four hours. There were significantly fewer patients with the death rattle who received scopolamine butylbromide compared to placebo (13% vs. 27%; difference: 14% [95% CI: 2-27]; p= 0.02). The instantaneous risk of the death rattle was reduced in the scopolamine butylbromide cohort compared to placebo (hazard ratio: 0.44 [95% CI: 0.20-0.92]; p= 0.03). Additionally, adverse events (restlessness, dry mouth, and urinary retention) and symptoms (pain, dyspnea, nausea, vomiting) did not significantly differ between intervention groups. Overall, dying patients receiving prophylactic scopolamine butylbromide demonstrated a reduction in the death rattle with no increase in adverse events. Notably, this study was limited to patients without a respiratory infection; therefore, it is unclear whether prophylactic scopolamine butylbromide reduces the incidence of the death rattle in dying patients concomitantly suffering from respiratory illness.

Relevant Reading: Randomized double-blind trial of sublingual atropine vs placebo for management of death rattle

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