High-Flow Nasal Cannula Versus Conventional Oxygen Therapy in Relieving Dyspnea in Emergency Palliative Patients With Do-Not-Intubate Status: A Randomized Crossover Study
Authors: Wansiri Chaisirin
Usapan Surabenjawong
Tipa Chakorn
Thawonrat Dorongthom
Nattakarn Praphruetkit
Tanyaporn Nakornchai
Apichaya Monsomboon
Onlak Ruangsomboon
Chok Limsuwat
Sattha Riyapan
Journal: Annals of emergency medicine (2020)
Discipline: CLINICAL MEDICINE
Keywords: Palliative patients; emergency department; respiratory distress; end-of-life; dyspnea
Affiliations: Department of Emergency Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand., Department of Emergency Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. Electronic address: .

Abstract:  Study objective: Palliative patients often visit the emergency department (ED) with respiratory distress during their end-of-life period. The goal of management is alleviating dyspnea and providing comfort. High-flow nasal cannula may be an alternative oxygen-delivering method for palliative patients with do-not-intubate status. We therefore aim to compare the efficacy of high-flow nasal cannula with conventional oxygen therapy in improving dyspnea of palliative patients with do-not-intubate status who have hypoxemic respiratory failure in the ED. Methods: This randomized, nonblinded, crossover study was conducted with 48 palliative patients aged 18 years or older with do-not-intubate status who presented with hypoxemic respiratory failure to the ED of Siriraj Hospital, Bangkok, Thailand. The participants were randomly allocated to conventional oxygen therapy for 60 minutes, followed by high-flow nasal cannula for 60 minutes (n=24) or vice versa (n=24). The primary outcome was modified Borg scale score. The secondary outcomes were numeric rating scale score of dyspnea and vital signs. Results: Intention-to-treat analysis included 44 patients, 22 in each group. Baseline mean modified Borg scale score was 7.6 (SD 2.2) (conventional oxygen therapy first) and 8.2 (SD 1.8) (high-flow nasal cannula first). At 60 minutes, mean modified Borg scale score in patients receiving conventional oxygen therapy and high-flow nasal cannula was 4.9 (standard of mean 0.3) and 2.9 (standard of mean 0.3), respectively (mean difference 2.0; 95% confidence interval 1.4 to 2.6). Results for the numeric rating scale score of dyspnea were similar to those for the modified Borg scale score. Respiratory rates were lower with high-flow nasal cannula (mean difference 5.9; 95% confidence interval 3.5 to 8.3), and high-flow nasal cannula was associated with a significantly lower first-hour morphine dose. Conclusion: High-flow nasal cannula was superior to conventional oxygen therapy in reducing the severity of dyspnea in the first hour of treatment in patients with do-not-intubate status and hypoxemic respiratory failure. 

Retracted: No

PubPeer comments:
 We read the article by Ruangsomboon et al.1 with great interest, and we appreciate the efforts to reveal the benefit of a high-flow nasal cannula (HFNC) for dyspnea in palliative patients with hypoxic respiratory failure. However, we would like to point out three concerns. First, we are concerned that the article did not reveal the causes of a hypoxic condition. Dyspnea in palliative patients with hypoxic respiratory failure may be improved by non-invasive intervention other than oxygen therapy. The causes of hypoxic respiratory failure in palliative patients, especially with a malignancy, include pleural effusion, pericardial effusion, chronic obstructive pulmonary disease exacerbation, congestive heart failure, pulmonary embolism, lymphangitic carcinomatosis and pulmonary infection. Appropriate interventions such as thoracentesis,2 pericardiocentesis, and administration of diuretics and glucocorticoids3 can improve hypoxic respiratory failure within several hours. Moreover, it is expected that the using a fan, humidifying or cooling may improve dyspnea in palliative patients.4,5 Information should be provided to the readers about the causes of hypoxic respiratory failure and how the authors performed any intervention or not in order to better understand your article. Second, information regarding conventional oxygen therapy is not available. In general, we use a nasal cannula with a flow rate of less than 5 L min with a non-humidified system. However, 25 % of type of conventional oxygen therapy before intervention was a nasal cannula even though mean oxygen flow was 8 L min before intervention. We are concerned that these patients had discomfort because of higher flow conventional nasal cannula and it could be made the intervention effect weak. Detailed information regarding the nasal cannula device, oxygen flow of the nasal cannula and humidification of oxygen gas would help readers to better understand the results and to generalize this study. Third, there is no information about investigators who asked participants and evaluated the primary outcome. We are concerned that investigators have overestimated an intervention effect. As the authors mentioned, the lack of blinding of the devices may have a bias for outcome. However, not only devices but also investigators are important factors influencing the primary outcome because the primary outcome is measured by asking participants with a scale form. In this study, dyspnea in participants was evaluated every 15 minutes, and this evaluation was more frequent than that in a usual clinical setting. Therefore, we would like to know whether the authors tried to decrease bias about investigators who asked participants and evaluated the primary outcome. References 1. Ruangsomboon O, Dorongthom T, Chakorn T, et al. High-Flow Nasal Cannula Versus Conventional Oxygen Therapy in Relieving Dyspnea in Emergency Palliative Patients With Do-Not-Intubate Status: A Randomized Crossover Study. Ann Emerg Med 2019;:1-12. [Epub ahead of print] 2. Ferreiro L, Suu00e1rez-Antelo J, Valdu00e9s L. Pleural procedures in the management of malignant effusions. Ann Thorac Med. 2017;12:3-10. 3. Lin RJ1, Adelman RD, Mehta SS. Dyspnea in palliative care: expanding the role of corticosteroids. J Palliat Med. 2012;15:834-837. 4. Dy SM1, Apostol CC. Evidence-based approaches to other symptoms in advanced cancer. Cancer J. 2010;16:507-513. 5. Galbraith S1, Fagan P, Perkins P, et al. Does the use of a handheld fan improve chronic dyspnea? A randomized, controlled, crossover trial. J Pain Symptom Manage. 2010;39:831-838. ,