## 4 Discussion
[PERSON] et al. [74] demonstrated that the use of a helmet with CPAP by patients diagnosed with COVID-19 was able to maintain mean levels of paCO\({}_{2}\) between 36 and 39 mmHg, values similar to those found in this study for patients who did not need mechanical ventilation. However, the mean values for paO\({}_{2}\) reported in the study by [PERSON] et al. [74] were 72 to 79 mmHg, values lower than those found in this study, regardless of the need for intubation. It is noteworthy that paO\({}_{2}\) values >80 mmHg are desirable within the context of hypoxemia [75]. Oxygen saturation levels are also key parameters within this context. [PERSON] et al. [76] demonstrated that patients with a SaO\({}_{2}\) rate <90% had a higher risk of death when compared to patients with values >90%. This study reinforces the potential of using the bubble device, because the results found for this parameter were >90%, regardless of the day of monitoring. However, an important finding was the difference between SaO\({}_{2}\) and SpO\({}_{2}\) values, which has been reported in other studies involving patients diagnosed with COVID-19, in which the authors also point out that the levels found for SaO\({}_{2}\) are higher when compared to SpO\({}_{2}\)[77; 78; 79]. The difference between the values may be related to different factors, including pathophysiological issues that may affect the oxyhaemoglobin dissociation curve and might further complicate the interpretation of the SpO\({}_{2}\)[80]. In addition to analysis using blood samples, imaging is also seen as an important tool during the management of patients with COVID-19, especially because it is predictive of clinical outcome [81; 82]. Regarding the results found in this study, the analysis of imaging exams is similar to the typical results of COVID-19 already described in the literature [83; 84; 85]. The results reported by [PERSON] et al. [86] demonstrated that patients diagnosed with COVID-19 who required non-invasive ventilation and those who required tracheal intubation had a similar pattern of pulmonary findings, and ground-glass opacities, consolidations, and mosaic paving were the most frequent in both the groups. Different authors have reported that the degree of pulmonary impairment identified during hospital admission can be a crucial predictor of the need for ICU admission or early death [87; 88; 89]. [PERSON] et al. [90] demonstrated that patients diagnosed with COVID-19 who have >50% pulmonary impairment are more likely to die early. However, in our study, among the 35 patients not intubated, 68.8% had pulmonary impairment >50%, indicating the importance of using the device to prevent the worsening of SARS-CoV-2 infection. Finally, it is noteworthy that hemodynamic and hemogasonetric conditions, as well as the presence of comorbidities and tomographic findings, are factors directly related to the need for mechanical ventilation in patients diagnosed with COVID-19; thus, the use of only the proposed device cannot be fully associated with the outcome related to the absence of the need for tracheal ventilatory support. However, the use of the bubble device can contribute to the maintenance of important physiological parameters of breathing and to the optimization of pulmonary oxygenation.