Definition
Excessive respiratory tract secretions (also referred to as death rattle) is the term used to describe a rattling noise produced by accumulated secretions in the airway that oscillate in time with inspiration and expiration. Generally occurs in patients who are extremely weak and close to death.

Scope
- Excessive respiratory tract secretions are associated with decreased consciousness and associated depression of reflexes (cough and swallow) at end of life. The patient is unlikely to be aware of, or distressed by, accumulated respiratory secretions.
- Management of this symptom is therefore primarily for the benefit of those present in the last hours and days.
- Nonpharmacological management includes positioning (and in some cases oropharyngeal suction) to reduce accumulation of secretions.

Antimuscarinic drugs in the management of excessive respiratory tract secretions
Antimuscarinic drugs (hyoscine hydrobromide, hyoscine butylbromide and glycopyrronium) can be effective in drying of respiratory secretions but there is no substantial evidence from systematic review that any intervention is superior to placebo in the treatment of this symptom.

Evidence for management of this symptom with antimuscarinic agents
• A recent systematic review on antimuscarinic drugs found no difference between hyoscine hydrobromide, hyoscine butylbromide, and glycopyrronium. Only one methodologically weak trial compared hyoscine hydrobromide to placebo.
• Antimuscarinic drugs reduce the production of saliva and have some effect on reducing respiratory secretions.
• Considering the lack of evidence from clinical trials, the recommendation for the use of antimuscarinic drugs in the management of excessive respiratory tract secretions has to be based on clinical expertise. Expert opinion strongly supports the use of these medications in palliative care patients in the terminal stage with respiratory secretions.
• There is considerable experience in the use of antimuscarinic drugs in the management of excess salivation and drooling in patients with neurological disabilities.
• Antimuscarinic drugs are less likely to be effective when secretions are the result of lung abnormalities (e.g., bronchial secretions) or reflux of gastric contents.

Recommended medicine: HYOSCINE BUTYLBROMIDE
Recommended formulations: 10 mg/mL injectable

• Hyoscine butylbromide is a peripherally acting antimuscarinic, anticholinergic agent used as an abdominal-specific antispasmodic. It is a quaternary ammonium compound that blocks the action of acetylcholine at parasympathetic sites (both muscarinic and nicotinic receptors) in smooth muscle and in secretory glands. It causes decreased motility of the gastrointestinal tract and the urogenital tracts, and is useful in the treatment of spasms in these regions.
• Several pharmacokinetic studies in humans have consistently demonstrated the low systemic availability of hyoscine butylbromide after oral administration, with plasma concentrations of the drug generally being below the limit of quantitation. Its bioavailability, estimated from renal excretion, was generally <1%. However, because of its high tissue affinity for muscarinic receptors, it remains available at the site of action in the intestine and exerts a local spasmolytic effect
• Relatively short duration of action (<1 hour) following single subcutaneous dose, but effect is prolonged with repeated doses.
• It is available in formulations for administration by oral and parenteral routes, and is generally the agent of first choice to control excessive secretions.
• Because it does not cross the blood-brain barrier, it may be preferred over hyoscine hydrobromide for patients at the end of life.

Adapted from Radbruch L et al. Essential medicines in palliative care — An application for the 19th WHO Expert committee on the selection and use of essential medicines. Kindle Edition, 135 pp. Published June 5, 2013 by IAHPC Press. Available at https://www.amazon.com/Essential-Medicines-Palliative-Care-Application-ebook/dp/B00D7S2D0C