## 5 Conclusions  
We conclude that using the bubble device to help the oxygen supplementation for patients with hypoxemia during the treatment of COVID-19 pneumonia could be an alternative in clinical practice aimed to reduce the number of mechanical ventilation through tracheal intubations. Of the 51 patients included in the study, 68.63% (\(n\) = 35) did not need invasive mechanical ventilation during the evaluated period (7 days), even in those patients with comorbidities and a pulmonary impairment >50% associated with SARS-CoV-2 pneumonia. The use of the bubble device caused a significant difference in the levels of SpO\({}_{2}\) comparing the day of initiation (D0) with the days of monitoring (D1, D4 and D7) and may have contributed to the mean SaO\({}_{2}\) of all study participants being >97%, as well as to the levels of paO\({}_{2}\) and paCO\({}_{2}\) being maintained in a controlled manner, according to the desirable values. Nevertheless, the highly complex treatment should be saved to critically ill patients when an efficient alternative could be tried first. Indeed, mechanical ventilation is a necessary procedure to save the lives of patients with severe respiratory failure. The bubble device can contribute to the optimization of pulmonary oxygenation, making it an alternative to support the treatment of patients with COVID-19 in the condition of severe hypoxemia. Furthermore, it is noteworthy that this was the first clinical trial with this device, which opens up the possibility of conducting new clinical trials with a larger sample size and more trial sites involved. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app12126052/s1](https://www.mdpi.com/article/10.3390/app12126052/s1)]([https://www.mdpi.com/article/10.3390/app12126052/s1](https://www.mdpi.com/article/10.3390/app12126052/s1)), Table S1. Questionnaire for collecting data on the perception of devices by patients; Table S2. Questionnaire for collecting data on the perception of devices by health professionals; Table S3. Questionnaire for collecting data on the perception of devices by cleaning professionals (sanitization); Table S4. Baseline data, vital signs, and blood gases of the 51 patients who joined the study, considering the analysis of the primary outcome. **Author Contributions:** Conceptualization, L.A.B.M., B.A.S.M., L.C.d.O.J., V.S.O. and R.B. ; Data curation, L.M.N., L.L.d.C., L.C.d.O.J., V.S.O. and R.B. ; Formal analysis, L.A.B.M., B.A.S.M., K.V.S.H., S.F.d.O.J., L.R.L.D.A., U.F.T.d.S. and L.L.d.C. ; Funding acquisition, L.A.B.M. ; Investigation, L.A.B.M., V.E.B., L.M.N., S.F.d.O.J., L.R.L.D.A., U.F.T.d.S., V.S.O. and R.B. ; Methodology, B.A.S.M., V.E.B., K.V.S.H., L.M.N., S.F.d.O.J., L.R.L.D.A., U.F.T.d.S., L.L.d.C., L.C.d.O.J., V.S.O. and R.B. ; Project administration, B.A.S.M., T.B., S.F.d.O.J. and L.R.L.D.A. ; Software, K.V.S.H. ; Supervision, L.A.B.M., B.A.S.M., T.B., L.R.L.D.A., U.F.T.d.S., L.C.d.O.J., V.S.O. and R.B. ; Validation, L.A.B.M., T.B. and L.C.d.O.J. ; Visualization, B.A.S.M. and T.B. ; Writing-original draft, L.A.B.M., B.A.S.M., V.E.B., K.V.S.H. and R.B. All authors have read and agreed to the published version of the manuscript. This research received no external funding. **Institutional Review Board Statement:** The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board (or Ethics Committee) of SENAI CIMATEC University Center (No. 4,153,349 and date of approval was 14 July 2020). **Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study. **Data Availability Statement:** The data presented in this study are available on request from the corresponding author. **Acknowledgments:** We are indebted to the medical staff team of all three hospitals: Espanhol Hospital, Hospital Cleriston Andrade, and Hospital Unimed of Feira de Santana.