Aspiration pneumonia combined with respiratory failure is a common cause of death in patients that have experienced a stroke. The primary treatment of this condition is to rapidly correct the hypoxia state, improve the oxygen supply to the tissue, and use antibiotics to prevent multiple organ failure from hypoxia . HFNC is a new type of oxygen therapy that not only can provide relatively stable oxygen concentrations and highly efficient airway humidification but also can regulate the flow velocity to provide positive end-expiratory pressure in the respiratory tract, similar to that which would be provided by a ventilator. HFNC is also better tolerated and has a better treatment effect than traditional invasive modes of oxygen therapy [16, 17]. Studies from many countries have shown that, in addition to significantly improving oxygenation status and tolerance, HFNC can reduce the incidence of re-intubation in patients with chronic obstructive pulmonary disease [18, 19]. HFNC has also played an important role in the treatment of viral pneumonia, including MERS-CoV pneumonia, H1N1 pneumonia, and novel coronavirus pneumonia. It has become part of a relatively standardized treatment protocol and has achieved a good therapeutic effect . The traditional mode of oxygen therapy often has a poor effect for patients that experience complications from aspiration pneumonia after a stroke: Injury to their central nervous system leads to limited respiratory function and a reduced ability to discharge phlegm autonomously, and these patients will inevitably require invasive auxiliary ventilation, increasing their medical burden. In addition, the prognosis of patients that also experience ventilator-associated pneumonia is very poor.
To improve the oxygenation status of patients and avoid tracheal intubation, it is necessary to identify a non-invasive mode of oxygen therapy that is more effective than traditional modes of oxygen therapy. Through the retrospective analysis of 87 patients with post-stroke aspiration pneumonia and respiratory failure, it was found that HFNC significantly improved the patients’ oxygenation status and was especially effective for the early and rapid correction of hypoxia. As shown by the contour map (Fig. 1), the oxygenation indices of the HFNC group began to improve approximately 4 h after therapy, and the improvement in oxygenation indices after 8–24 h was significantly greater than in the traditional Venturi mask treatment group. Repeated measurement statistics demonstrated that HFNC therapy contributed to the improvement of oxygenation indices at a rate of 75.1%. In addition, the proportion of patients with stroke sequelae was significantly higher in the Venturi group than in the HFNC group. Thus, the poorer results for the Venturi group may reflect both a longer stay in bed as well as serious pulmonary tissue injuries. In addition, it was also found that, within 72 hours after treatment, a significantly lower proportion of patients from the HFNC group required invasive ventilation than in the Venturi group, where the incidence of invasive ventilation in the HFNC group was 0.406 times than of the Venturi group. This suggests that HFNC could significantly reduce the incidence of transition to invasive auxiliary ventilation. However, the 28-day mortality rate of the two groups showed no obvious statistical difference.
The analysis of the general data for the patients in the two groups also revealed differences in terms of organ failure. A higher proportion of patients experienced multiple organ failure in the Venturi group than in the HFNC group. A study by He Ping et al.  found that the improvement of 90-day neurological function in patients that had experienced an acute stroke could be attributed to the improvement of oxygenation of organs, including brain tissue, during the early post-stage. However, the study did not specifically analyze the time at which the patients’ hypoxic state was significantly corrected, and all of the enrolled patients were in the acute stage of stroke (within 24 hours of onset) and had not experienced organ failure. By contrast, the patients enrolled in the present study were all in the post-stroke sequelae stage, and some were experiencing multiple organ failure. As a result, this study found significantly higher rates of mortality and invasive auxiliary ventilation than were reported in the study mentioned above.
The present study had some limitations. First, the results may have been impacted by the sample size. Second, the results may have been biased because the study was not stratified according to the specific organs that failed, the number of organs that failed, or the duration of stroke sequelae. The results must be verified by a stratified randomized controlled study.