Background: High-flow nasal cannula (HFNC) may help avoid intubation of hypoxemic patients suffering from COVID-19; however, it may also contribute to delaying intubation, which may increase mortality. Here, we aimed to identify the predictors of HFNC failure among patients with COVID-19.Methods: We performed a multicenter retrospective study in China from January 15 to March 31, 2020. Two centers in Wuhan (resource-limited centers) enrolled 32 patients, and four centers outside Wuhan enrolled 34 cases. HFNC failure was defined as the requirement of escalation therapy (NIV or intubation). The ROX index (the ratio of SpO2/FiO2 to the respiratory rate) was calculated.Results: Among the 66 patients, 29 (44%) cases experienced HFNC failure. The ROX index was much lower in failing patients than in successful ones after 1, 2, 4, 8, 12, and 24 h of HFNC. The ROX index was independently associated with HFNC failure (OR = 0.65; 95% CI: 0.45–0.94) among the variables collected before and 1 h after HFNC. To predict HFNC failure tested by ROX index, the AUC was between 0.73 and 0.79 for the time points of measurement 1–24 h after HFNC initiation. The HFNC failure rate was not different between patients in and outside Wuhan (41% vs. 47%, p = 0.63). However, the time from HFNC initiation to intubation was longer in Wuhan than that outside Wuhan (median 63 vs. 22 h, p = 0.02). Four patients in Wuhan underwent intubation due to cardiac arrest; in contrast, none of the patients outside Wuhan received intubation (13 vs. 0%, p = 0.05). The mortality was higher in Wuhan than that out of Wuhan, but the difference did not reach statistical significance (31 vs. 12%, p = 0.07).Conclusion: The ROX index can be used to predict HFNC failure among COVID-19 patients to avoid delayed intubation, which may occur in the resource-limited area.

IntroductionThe incidence of postoperative pulmonary complications (PPCs) following thoracic surgery is high, which increases the mortality rate, prolongs the length of hospital stay and increases medical costs. Some studies have confirmed that preoperative risk assessment, intraoperative anaesthesia methods and intraoperative mechanical ventilation strategies, including recruitment manoeuvres (RMs), can reduce the incidence of PPCs. Despite these improved strategies, the incidence of PPCs remains high. However, mechanical ventilation strategies have not been studied in the postoperative period.Methods and analysisWe assume that RM during mechanical ventilation with sequential high-flow nasal oxygen therapy (HFNO) after extubation can maintain the opening of the postoperative alveoli and ultimately reduce the incidence of PPCs after thoracic surgery. We will include thoracic surgery patients and divide them into the RM with sequential HFNO group and the control group. They will be given RMs and sequential HFNO or be given conventional treatment. The sample size is 654 adult patients (327 per group) undergone thoracic surgery and presenting to the intensive care unit.Ethics and disseminationThis study was approved by the Biomedical Research Ethics Committee of West China Hospital of Sichuan University (REC2019-730). It is expected that this study will lead to a randomised controlled trial. We assume that the findings will provide more evidence about PPCs and improve the management of patients undergone thoracic surgery.Trial registration numberChiCTR2100046356.

IntroductionA number of published studies have revealed that lung recruitment can improve oxygenation, shorten the duration of mechanical ventilation (MV) and decrease mortality in adults with acute hypoxaemic respiratory failure, especially patients with acute respiratory distress syndrome. However, few articles have assessed lung recruitment in paediatric patients, especially after cardiac surgery. This clinical trial aimed to determine whether lung recruitment can reduce the duration of MV in paediatric patients with hypoxaemic respiratory failure after cardiac surgery.Method and analysisIn this trial, we will randomly assign 234 paediatric patients (aged 28 days to 14 years) within 72 hours after cardiac surgery with an arterial oxygen tension (PaO2) to fraction of inspired oxygen (FiO2) ratio (PaO2/FiO2) of <300 to either a lung recruitment group or a conventional group. The primary endpoint will be the duration of MV. The secondary endpoints will be ventilator-free days, PaO2/FiO2, respiratory system compliance, duration of non-invasive ventilation, reintubation rate, length of intensive care unit stay, length of hospital stay, occurrence of serious adverse events (barotrauma, persistent hypotension and arrhythmia), postoperative pulmonary complications.Ethics and disseminationThe ethics committee of West China Hospital of Sichuan University granted ethics approval for this study (20 August 2019). The results will be published in peer-reviewed journals and presented at conferences.Trial registration numberChiCTR1900025990.