Death rattle: current experiences and non-pharmacological management—a narrative review

Introduction

Death rattle (DR) is a common symptom in patients who are close to death. It is caused by an accumulation of secretions in the upper airway which dying patients cannot effectively cough up or ingest, as a result of diminished consciousness (1-3). Two subgroups of DR exist: DR type 1 or the ‘real’ DR due to predominantly salivary secretions and DR type 2 or the ‘pseudo’ DR due to predominantly bronchial secretions secondary to infection or pulmonary diseases (4,5). The reported prevalence of DR in general varies considerably, averaging around 50% (6-8).

The way DR is experienced can differ between patients, relatives, and health professionals. Since patients have a decreased consciousness when DR develops, one could assume they might not be aware of the sound (9,10). However, the precise patients’ perception is difficult to evaluate (1). To date, there is no evidence available about the association between DR and respiratory distress (1,9,11). DR-related experiences among relatives and health professionals vary. Regarding relatives, some of them report DR as a distressing symptom, possibly related to their judgement of whether the patient is comfortable. Other relatives think of it as a useful warning sign of imminent death (2,12,13). DR can also impact health professionals, influencing their choice of whether or not to intervene (2,14). However, evidence of patients’, relatives’, and health professionals’ needs for DR management in order to improve their experiences is lacking.

Regarding pharmacological interventions for DR management, anticholinergics are the most common drug of choice. A recent randomized controlled trial showed their effectiveness when given prophylactically (15). However, in current practice, anticholinergics are mostly administered when DR is already onset, despite the fact that current evidence does not support their effect when started after the occurrence of DR (1-3,16). The most frequently used non-pharmacological interventions in DR management are repositioning of the patient, suctioning of secretions, reducing hydration levels, and communication about DR with relatives (2,3,17). To date, little is known about the actual effect of these non-pharmacological interventions on DR intensity or on the distress perceived by relatives and health professionals related to DR.

Therefore, this narrative review aims to explore (I) the current experiences and needs of patients, family and health professionals related to DR sound and its management; and (II) studies on non-pharmacological interventions in DR management. We present this article in accordance with the Narrative Review reporting checklist (available at https://apm.amegroups.com/article/view/10.21037/apm-23-507/rc).

Methods

We conducted a search in Medline via PubMed with the free-text term “death rattle” on January 3^rd, 2023, and included papers published in the last ten years. First, all duplicates were removed and title and abstract screening was performed by two independent researchers (L.M. and E.O.). Conflicts were resolved with a third researcher (M.D.R.). Second, full texts were assessed based on predetermined selection criteria. The search strategy summary is provided in Table 1 and a screening procedure is provided in Figure 1. Extracted data included: first author, country, year of publication, study design, setting, population, in- and exclusion criteria, sample sizes, objectives and results concerning measurement tools used, experiences of DR and non-pharmacological interventions. As this is a narrative review, no meta-analysis was conducted.

Figure 1 PRISMA flowchart of screening procedure and identified studies for inclusion.

Results

Nine studies were included in this review: seven observational and two qualitative studies. A summary of the included studies is shown in Table 2.

We found one study reporting on the perceived patients’ experiences of DR (6). This prospective observational study evaluated the relationship between DR intensity, scored by the Death Rattle Intensity Scale (DRIS), and patients’ respiratory distress, evaluated by the Respiratory Distress Observation Scale (RDOS). No differences were found in respiratory distress when comparing patients with and without DR, nor was there a significant correlation between DR intensity and respiratory distress (6).

Three studies focused on bereaved relatives’ experiences regarding different aspects of DR and its management (18-20). A qualitative interview study, by van Esch et al. [2020], found no positive experiences of the sound of DR and reported that most relatives had experienced DR as a distressing symptom. Other than the actual sound of DR, insecurities about the burden of DR for the patient, a longer duration of DR, and previous experience with DR were also found to negatively impact relatives’ experiences. The amount and quality of information given by health professionals did not seem to influence relatives’ experience of DR. However, when other symptoms such as dyspnea, restlessness, or delirium prevailed, the experience of DR seemed less burdensome for relatives (18). Yamaguchi et al. [2022] reported a poor correlation between physician-evaluated and bereaved family-perceived DR intensity, with generally lower scores for bereaved family perceptions of DR intensity. According to the researchers, this suggests relatives’ emotional distress might not be correlated with DR intensity (19). Lastly, Shimizu et al. [2014] investigated DR related emotional distress levels of bereaved relatives and their perceptions of the need for DR care improvement. They reported that 66% of bereaved relatives who experienced DR, had high levels of distress and 53% had a strong need for DR care improvement (20).

Health professionals’ attitudes towards and decision-making in prescribing or administering pharmacological or non-pharmacological interventions was described in one study (21). This study reported that health professionals are often influenced in their decision making to prescribe or administer medication by external pressure from colleagues or their own need to ‘do something’, even if they thought it was not beneficial for the patient (21).

Regarding studies on non-pharmacological interventions, we found one study that investigated the effectiveness of a non-pharmacological intervention, suctioning, as their secondary endpoint (22). The effect of suctioning on DR improvement before starting anticholinergics was tested, showing that the severity of DR did not improve when suctioning was performed (P=0.13) (22). No additional studies were found reporting on the observed effect of other non-pharmacological interventions.

Seven studies reported on experiences related to at least one non-pharmacological intervention for DR, either as a primary (19,23,24) or secondary (18,20,21,25) endpoint.

The perceived role of repositioning of the patient in DR management was reported in two studies (21,24). The first study, a survey study among certified palliative care physicians showed that 51% of participants would (very) often perform repositioning as an intervention for DR (24). The other study, a focus group study by Hirsch et al. [2013] mentioned that specialist health professionals from palliative care units agreed on repositioning patients as a useful first line intervention (21).

Three studies reported on different aspects of suctioning as an intervention to reduce DR intensity (19,20,24). Matsunuma et al. [2020] found that 29% and 46% of Japanese palliative care physicians would often perform oropharyngeal suctioning for type 1 and type 2 DR, respectively (24). Shimizu et al. [2014] focused on relatives’ experiences related to suctioning. Of family members whose relative underwent suctioning, 62% reported patient discomfort during suctioning, 72% reported temporary improvement and 25% enduring improvement of DR after suctioning (20). In a study by Yamaguchi et al. [2022], 77.5% of the relatives thought the sound of DR decreased and 73% reported that patients became more comfortable after suctioning. One quarter, 25.7%, of bereaved relatives experienced a need for care improvement related to suctioning. A positive correlation was found with the patient showing a distressing face during suctioning. Having thorough discussions about suctioning with physicians or nurses and a perceived gentle performance of suctioning was found to be negatively correlated with bereaved relatives’ need for care improvement related to suctioning (19).

The effect of fluid administration during end-of-life care was reported on in two studies (23,25). The first explored the correlation between provision of subcutaneous hydration 6 days before death and the incidence of DR. While they found a positive correlation between subcutaneous hydration and DR incidence, no statistically significant relationship was found (23). The other study reported on the effect of relevant influencing clinical factors, as among which fluid administration, on DR’s characteristics. No significant differences between variables concerning DR were found (25).

Three studies described the experiences related to communication and information about DR as a non-pharmacological intervention (18,20,21). Hirsch et al. [2013] found that explaining DR to relatives was perceived as a useful first line intervention by health professionals (21). The survey study of Shimizu et al. [2014] showed that higher distress levels were reported by family members who were unaware about DR being a natural phenomenon, with 56% of participants reporting an inadequate explanation of it being a natural phenomenon and 33% reporting a lack of explanation about DR causes (20). Lastly, van Esch et al. [2020] showed that relatives’ experiences of DR do not seem to be influenced by the amount and quality of information given by health professionals (18).

Discussion

This narrative review aimed to explore the current experiences and needs of patients, family and health professionals related to DR sound and its management and to describe non-pharmacological interventions in DR management. Overall, we demonstrated that DR-related experiences differ among patients, relatives, and health professionals. Some bereaved relatives express a need for DR care improvement but to date, the effectiveness of non-pharmacological interventions for DR management remains unclear.

An editorial by Lowe and Hanson [2021] states that one should acknowledge that the internal experience of the dying, nonverbal patient cannot be fully known (16). As the hearing of a dying patient seems to be preserved throughout the dying process, there is always the possibility the patient can hear their own DR. However, the capacity for awareness during the unresponsive period leading up to a “natural” death is unknown (26,27). So it may be that one hears its own DR, but is not capable of ‘listening to it’ anymore. The assumption that patients do not experience distress related to DR sound, due to their decreased consciousness, seems to be confirmed by the one study found focusing on patients’ experience of DR by Campbell et al. [2013], who used the RDOS to measure patients’ distress (6). This scoring scale has strong validity, reliability and cut-point determination psychometrics and is not subject to investigator interpretation, unlike other scales used in this setting, which are subject to the interpretation of health professionals which can inherently lead to an (inter)observer bias, such as the DRIS evaluating DR intensity (10,28).

Although it remains unclear how patients experience DR, we found four studies reporting that DR can cause significant distress and concerns in relatives (18-21). Again, an important consideration in the interpretation of these findings is the measurement tools used in these studies. For example, Yamaguchi et al. [2022] examined the sensitivity and specificity of the DRIS score for detecting bereaved relatives’ distress levels related to DR and found a low accuracy of prediction [area under the curve (AUC) =0.62]. This strongly indicates that the DRIS is not a useful tool for detecting DR-related distress levels in bereaved relatives and that DR intensity might not be an appropriate outcome measure to quantify DR-related distress (19). Additionally, in two of the included studies, questionnaires consisting of Likert scales were used to capture perceived distress in bereaved relatives and were developed by the research team based on literature review and discussion among specialists in palliative care (e.g., physicians and nurses) (20,24). We could not find any standardized or validated questionnaire for measuring relatives’ DR-related distress. Therefore, we suggest that future research should focus on the development of a reliable measurement tool to objectify DR-related outcomes. Furthermore, the contributing factors of higher distress levels among relatives reported by both Shimizu et al. [2014] and van Esch et al. [2020] should be taken into account and evaluated in future research. Reported contributing factors are (I) relatives’ own fear of imminent death; (II) making distressing interpretations about DR; (III) unawareness of DR being a natural phenomenon; (IV) insecurities about the burden of DR for the patient; (V) previous experiences with DR; (VI) a longer duration of DR; (VII) a younger patient age; and (VIII) being married to the patient. It is important for health professionals to become aware of these factors to identify relatives with a greater chance of experiencing distress. Secondly, most of these factors, except for the patient’s age and the relationship status with the patient, could possibly be alleviated or even prevented by either general or factor specific interventions, such as the provision of adequate nursing care as well as accurate information and communication (18,20). This is supported by a recent survey showing that relatives provided with information about the dying phase have more understanding about this phase and have a better ability to make informed decisions. In addition, relatives feel more comfortable about staying with the dying patient when prepared about the situation by clear communication (29). However, it should be noted that van Esch et al. [2020] mentioned that information given by health professionals did not seem to influence relatives’ experience of DR (18). More research is needed to further determine which relatives are most in risk of distress and how to best identify them. Additionally, a stronger body of evidence is needed regarding the efficacy of non-pharmacological interventions, such as education and communication, to reduce DR-related distress levels in relatives.

Currently, there is only limited insight in patients’, relatives’ or health professionals’ needs regarding DR care. One Japanese study reported that half of bereaved relatives experience a strong need for DR care improvement. One major contributing factor of a higher family-reported need for DR care improvement was the family members’ experience of inadequate nursing care (20). This emphasizes the importance of well-trained nursing staff in end-of-life care and the need to educate relatives about the course of end-of-life care. Overall, additional research into the needs of both patients, relatives, and health professionals to optimize DR care is warranted.

This review found that health professionals’ decision-making regarding interventions seems to be influenced by reasons not directly related to relieving the distress of the dying patient (21). This has also been reported in other research, suggesting that health professionals’ responses and decisions are influenced by the way in which they make sense of DR and their own perception of its effect on relatives rather than on patients (2,14). It seems that the need ‘to do something’ is so deeply ingrained in health professionals’ culture of care that it is necessary to make them aware of their own perceptions and behaviors, as they are the ones carrying out DR care for both patients and relatives. A better understanding of contributing factors to health professionals’ decision-making seems needed in order to optimize current DR management.

A recent paper discusses the thought processes and clinical approach for pharmacological DR management of three experts in the field. A disparity in their opinions exists, as they have different ethical considerations in mind when making decisions (30). Taking into account the principle of nonmaleficence, some may consider it morally questionable to treat a patient, of whom the level of DR-related distress is not known, with medication that may result in patient discomfort or distress through associated side effects (e.g., dry mouth, constipation, urinary retention) and of which no strong evidence exists to support their use in DR treatment once DR is onset (3,11,30-34). One expert in the paper suggests the prophylactic treatment of DR as a promising strategy, as recent evidence suggests anticholinergics may be more effective if used as prophylaxis for DR (15,16,30,35). However, identifying patients at high-risk of developing DR is difficult, so selective prophylactic treatment of only those patients is currently not possible (11,31). With the prevalence of DR estimated at 50% on average, systematically treating all patients prophylactically with medication would entail that one out of two patients could be treated unnecessarily. This brings up the ethical issue of medical futility defined as the clinical action which does not serve a useful purpose in attaining a specified goal, in this case being the patient’s comfort (34). Finally, another clinical justification of using medications in the treatment of DR seems to be assuaging the distress of relatives (30). However, when choices to intervene are based on helping relatives rather than the patient this implies another ethical dilemma. As some may think treating a patient to decrease their DR sound is a helpful way of assuaging listeners’ distress, others might consider this as maleficent and would rather focus on interventions directly focused on relatives (30).

With all these ethical and practical considerations surrounding pharmacological management of DR, our group believes the priority for research should be aimed towards nonpharmacological management for DR treatment, concerning interventions such as repositioning of the patient, suctioning, and comprehensive communication strategies (3,10,32). However, the only study investigating the effectiveness of suctioning before starting anticholinergics reported no improvement of DR due to the intervention (15). Hirsch et al. [2013] suggested that repositioning of patients and communication with relatives can be useful first line interventions, yet the effect on perceived DR intensity or distress levels among relatives or health professionals has not been studied (21). One included study found a positive correlation between subcutaneous hydration and DR incidence (23). A recent retrospective study supports these findings, with a high hydration level (>500 mL/day) one week before death significantly associated with a higher incidence of DR 48 hours before death (36). However, to our knowledge, no studies exist focusing on the effectiveness of reducing hydration levels for DR incidence. As such, this supports the conclusion of several other reviews in stating that there is an urgent need to study the effectiveness of non-pharmacological interventions for DR management (2,31,32).

Another important point of concern is the outcome measures used in the evaluation of (non-pharmacological) interventions. Currently, the mostly used outcome measure is a decrease in DR intensity. For its measurement, the Victoria Respiratory Congestion Scale (VRCS) and the DRIS are the most commonly used tools (6,19,22,25). These are two numeric scales which need to be filled out by a health professional, which can lead to (inter)observer bias. A recent validation study by Tantiwatniyom et al. [2022] showed criterion-related validity and reliability of the Thai VRCS to objectively assess DR intensity, but this is the only validation study we could find (37). Another and possibly more useful outcome measure could be the alleviation of DR-related distress within bereaved relatives or health professionals. A problem arises here, as DRIS is often used to capture DR-related distress in relatives and as earlier discussed; DR intensity might not be an appropriate outcome measure to quantify DR-related distress (4). Therefore, researchers should first reflect on the outcome measure they want to objectify in order to determine which measurement tool is most appropriate to use.

Two important methodological limitations of this narrative review need to be addressed. First, this review only included articles published in the last ten years. This decision was based on the availability of the systematic review of Lokker et al. [2014], in which articles published up to August 2012 were included (2). This narrative review aimed to provide researchers and health professionals with new or additional insights into DR management. Second, we did not conduct a multicomponent search strategy in different databases. Rather we used a targeted approach based on the most relevant key word in PubMed, which was in line with the scope of this narrative review, i.e., to map the most recent literature on DR and formulate avenues for further research. Hence, some key papers might have been missed. In addition, some methodological elements of the included studies should be considered in the interpretation of the results. First, three of the ten included studies were conducted in Japan. Given that DR experiences might be subject to cultural differences, the generalizability of the results might be limited. Second, all included articles on relatives’ experiences related to DR were carried out retrospectively with bereaved family members. This may have caused recall bias in the bereaved family members’ responses. However, conducting research in a terminal setting with patients, relatives and health professionals remains a challenge because of both ethical and methodological considerations (38).

Conclusions

This narrative review provides insight into some of the more understudied topics related to DR management and suggest avenues for further research. The assumption that patients are not disturbed by DR because of a decreased consciousness remains. Therefore, we should focus on the experiences and needs of relatives and health professionals. Variation in DR related distress within relatives exist, which can be influenced by different contributing factors. A better understanding of these factors seems needed in order to optimize current DR management. Also, health professionals are influenced in their decision-making to intervene for reasons not directly related to relieving the distress of the dying patient. Awareness of these behaviors is necessary to enhance DR care. The effectiveness of non-pharmacological interventions remains unclear, indicating more research is needed.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist (available at https://apm.amegroups.com/article/view/10.21037/apm-23-507/rc).

Peer Review File: Available at https://apm.amegroups.com/article/view/10.21037/apm-23-507/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://apm.amegroups.com/article/view/10.21037/apm-23-507/coif). E.O. serves as an unpaid palliative radiotherapy subcommittee member of Annals of Palliative Medicine from December 2022 to November 2024. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Mercadamte S. Death rattle: critical review and research agenda. Support Care Cancer 2014;22:571-5. [Crossref] [PubMed]
2. Lokker ME, van Zuylen L, van der Rijt CC, et al. Prevalence, impact, and treatment of death rattle: a systematic review. J Pain Symptom Manage 2014;47:105-22. [Crossref] [PubMed]
3. Taburee W, Dhippayom T, Nagaviroj K, et al. Effects of Anticholinergics on Death Rattle: A Systematic Review and Network Meta-Analysis. J Palliat Med 2023;26:431-40. [Crossref] [PubMed]
4. Bennett MI. Death rattle: an audit of hyoscine (scopolamine) use and review of management. J Pain Symptom Manage 1996;12:229-33. [Crossref] [PubMed]
5. Wildiers H, Menten J. Death rattle: prevalence, prevention and treatment. J Pain Symptom Manage 2002;23:310-7. [Crossref] [PubMed]
6. Campbell ML, Yarandi HN. Death rattle is not associated with patient respiratory distress: is pharmacologic treatment indicated? J Palliat Med 2013;16:1255-9. [Crossref] [PubMed]
7. Yamaguchi T, Morita T, Shinjo T, et al. Effect of parenteral hydration therapy based on the Japanese national clinical guideline on quality of life, discomfort, and symptom intensity in patients with advanced cancer. J Pain Symptom Manage 2012;43:1001-12. [Crossref] [PubMed]
8. Morita T, Hyodo I, Yoshimi T, et al. Association between hydration volume and symptoms in terminally ill cancer patients with abdominal malignancies. Ann Oncol 2005;16:640-7. [Crossref] [PubMed]
9. Bradley K, Wee B, Aoun S. Management of death rattle: what influences the decision making of palliative medicine doctors and clinical nurse specialists? Progress in Palliative Care 2010;18:270-4. [Crossref]
10. Clark K, Butler M. Noisy respiratory secretions at the end of life. Curr Opin Support Palliat Care 2009;3:120-4. [Crossref] [PubMed]
11. Star A, Boland JW. Updates in palliative care - recent advancements in the pharmacological management of symptoms. Clin Med (Lond) 2018;18:11-6. [Crossref] [PubMed]
12. Wee BL, Coleman PG, Hillier R, et al. The sound of death rattle I: are relatives distressed by hearing this sound? Palliat Med 2006;20:171-5. [Crossref] [PubMed]
13. Wee BL, Coleman PG, Hillier R, et al. The sound of death rattle II: how do relatives interpret the sound? Palliat Med 2006;20:177-81. [Crossref] [PubMed]
14. Wee B, Coleman P, Hillier R, et al. Death rattle: its impact on staff and volunteers in palliative care. Palliat Med 2008;22:173-6. [Crossref] [PubMed]
15. van Esch HJ, van Zuylen L, Geijteman ECT, et al. Effect of Prophylactic Subcutaneous Scopolamine Butylbromide on Death Rattle in Patients at the End of Life: The SILENCE Randomized Clinical Trial. JAMA 2021;326:1268-76. [Crossref] [PubMed]
16. Lowe JR, Hanson LC. Preventing Death Rattle With Prophylactic Subcutaneous Scopolamine Butylbromide. JAMA 2021;326:1263-5. [Crossref] [PubMed]
17. Back IN, Jenkins K, Blower A, et al. A study comparing hyoscine hydrobromide and glycopyrrolate in the treatment of death rattle. Palliat Med 2001;15:329-36. [Crossref] [PubMed]
18. van Esch HJ, Lokker ME, Rietjens J, et al. Understanding relatives' experience of death rattle. BMC Psychol 2020;8:62. [Crossref] [PubMed]
19. Yamaguchi T, Mori M, Maeda I, et al. The impact of death rattle on bereaved families: not the sound itself, but the resonance with their feelings. Jpn J Clin Oncol 2022;52:774-8. [Crossref] [PubMed]
20. Shimizu Y, Miyashita M, Morita T, et al. Care strategy for death rattle in terminally ill cancer patients and their family members: recommendations from a cross-sectional nationwide survey of bereaved family members' perceptions. J Pain Symptom Manage 2014;48:2-12. [Crossref] [PubMed]
21. Hirsch CA, Marriott JF, Faull CM. Influences on the decision to prescribe or administer anticholinergic drugs to treat death rattle: a focus group study. Palliat Med 2013;27:732-8. [Crossref] [PubMed]
22. Yamaguchi T, Yokomichi N, Yamaguchi T, et al. Anticholinergic drugs for death rattle in dying patients with cancer: multicentre prospective cohort study. BMJ Support Palliat Care 2023;13:462-71. [Crossref] [PubMed]
23. Dayan D, Menahem S, Shvartzman P. When they stop drinking-examining end-of-life hydration practices and death rattle occurrence. Support Care Cancer 2021;29:179-85. [Crossref] [PubMed]
24. Matsunuma R, Suzuki K, Matsuda Y, et al. Palliative care physicians' perspectives of management for terminally ill cancer patients with death rattle: a nationwide survey. Jpn J Clin Oncol 2020;50:830-3. [Crossref] [PubMed]
25. Likar R, Michenthaler MC, Traar R, et al. Clinical factors influencing death rattle breathing in palliative care cancer patients: Non-interventional study. Z Gerontol Geriatr 2017;50:332-8. [Crossref] [PubMed]
26. Blundon EG, Gallagher RE, Ward LM. Electrophysiological evidence of preserved hearing at the end of life. Sci Rep 2020;10:10336. [Crossref] [PubMed]
27. Parnia S, Keshavarz Shirazi T, Patel J, et al. AWAreness during REsuscitation - II: A multi-center study of consciousness and awareness in cardiac arrest. Resuscitation 2023;191:109903. [Crossref] [PubMed]
28. Zhuang Q, Yang GM, Neo SH, et al. Validity, Reliability, and Diagnostic Accuracy of the Respiratory Distress Observation Scale for Assessment of Dyspnea in Adult Palliative Care Patients. J Pain Symptom Manage 2019;57:304-10. [Crossref] [PubMed]
29. Gerlach C, Baus M, Gianicolo E, et al. What do bereaved relatives of cancer patients dying in hospital want to tell us? Analysis of free-text comments from the International Care of the Dying Evaluation (i-CODE) survey: a mixed methods approach. Support Care Cancer 2022;31:81. [Crossref] [PubMed]
30. van Esch HJ, Campbell ML, Mori M, et al. Should (Prophylactic) Medications Be Used for the Management of Death Rattle? J Pain Symptom Manage 2023;66:e513-7. [Crossref] [PubMed]
31. Kolb H, Snowden A, Stevens E. Systematic review and narrative summary: Treatments for and risk factors associated with respiratory tract secretions (death rattle) in the dying adult. J Adv Nurs 2018;74:1446-62. [Crossref] [PubMed]
32. Wee B, Hillier R. Interventions for noisy breathing in patients near to death. Cochrane Database Syst Rev 2008;2008:CD005177. [Crossref] [PubMed]
33. Watts T, Willis D, Noble S, et al. Death rattle: reassuring harbinger of imminent death or a perfect example of inadequacies in evidence-based practice. Curr Opin Support Palliat Care 2019;13:380-3. [Crossref] [PubMed]
34. Akdeniz M, Yardımcı B, Kavukcu E. Ethical considerations at the end-of-life care. SAGE Open Med 2021;9:20503121211000918. [Crossref] [PubMed]
35. Mercadante S, Marinangeli F, Masedu F, et al. Hyoscine Butylbromide for the Management of Death Rattle: Sooner Rather Than Later. J Pain Symptom Manage 2018;56:902-7. [Crossref] [PubMed]
36. Yokomichi N, Morita T, Yamaguchi T. Hydration Volume Is Associated with Development of Death Rattle in Patients with Abdominal Cancer. J Palliat Med 2022;25:130-4. [Crossref] [PubMed]
37. Tantiwatniyom T, Nagaviroj K. A study to translate and validate the Thai version of the Victoria Respiratory Congestion Scale. BMC Palliat Care 2022;21:150. [Crossref] [PubMed]
38. van Esch HJ, Prins SD, van de Vathorst S, et al. Reflections on Including Patients in a Randomized Placebo-Controlled Multicentre Trial in the Dying Phase - the SILENCE Study. J Pain Symptom Manage 2022;63:e545-52. [Crossref] [PubMed]