Refer to the PDQ summary on Cardiopulmonary Syndromes for more information.
Rattle, also referred to as death rattle, occurs when saliva and other fluids accumulate in the oropharynx and upper airways in a patient who is too weak to clear the throat. Rattle does not appear to be painful for the patient, but the association of this symptom with impending death often creates fear and anxiety for those at the bedside. Rattle is an indicator of impending death, with an incidence of approximately 50% in people who are actively dying. There is some evidence that the incidence of rattle can be greatly reduced by avoiding the tendency to overhydrate patients at the end of life.[59,60]
In one prospective study of 100 terminally ill cancer patients, rattle began at an average of 57 hours before death.[Level of evidence: II] Other studies suggest the median time from onset of rattle to death is much shorter at 16 hours. Two types of rattle have been identified: real death rattle, or type 1, which is probably caused by salivary secretions; and pseudo death rattle, or type 2, which is probably caused by deeper bronchial secretions due to infection, tumor, fluid retention, or aspiration.[60,63] In one retrospective chart review, rattle was relieved in more than 90% of the patients with salivary secretions, while patients with secretions of pulmonary origin were much less likely to respond to treatment.
The pharmacologic treatment of rattle includes antimuscarinic agents, which antagonize acetylcholine (and are thus termed anticholinergic) to reduce secretions. The most commonly used agents include scopolamine, glycopyrrolate, atropine, and hyoscyamine.[59,64] Few data exist to support the use of one agent or route over another. Because most patients are unable to swallow at this time, transdermal or parenteral routes are employed most frequently. Scopolamine, also called l-hyoscine or hyoscine, is available in oral, parenteral, transdermal, and ophthalmic formulations. Some clinicians begin treatment by applying one or two scopolamine transdermal patches behind the ear. Noticeable reduction in secretions usually occurs within 1 or 2 hours after application. If the patch is ineffective, a scopolamine infusion is initiated, with a starting dose of 50 µg per hour intravenously or subcutaneously and titrated upward to 200 µg or more per hour. Adverse effects include CNS depression, although paradoxical excitation has been reported.