Application of high-flow nasal cannula in hypoxemic patients with COVID-19: a retrospective cohort study (preprint)

Background: High-flow nasal cannula (HFNC) oxygen therapy provides effective respiratory support in patients with hypoxemic respiratory failure. However, the efficacy of HFNC for patients with COVID-19 has not been established. This study was performed to assess the efficacy of HFNC for patients with COVID-19 and describe early predictors of HFNC treatment success in order to develop a prediction tool that accurately identifies the need for invasive mechanical ventilation (IMV). Methods: We retrospectively reviewed the records of patients with COVID-19 who underwent HFNC in 2 hospitals in Wuhan between 1 January and 1 March 2020. Overall survival, the success rate of HFNC treatment and respiratory variables to predict the outcome of HFNC treatment were evaluated.Results: A total of 105 patients were analyzed. Of these, 65 patients (61.9%) showed improved oxygenation and were successfully withdrawn from HFNC. The oxygenation index (PaO2/FiO2), Oxygen saturation index (SpO2/FiO2) and respiratory rate-oxygenation index (ROX index: SpO2/FiO2*RR) at 6h, 12h and 24h of HFNC initiation were closely related to the prognosis. The best predictor was the ROX index at 24h after initiating HFNC (area under the receiver operating characteristic curve, 0.874). In the multivariate logistic regression analysis, young age, gender of female, and lower SOFA score all have predictive value, while a ROX index greater than 6.10 at 24 h after initiation was significantly associated with HFNC success (OR, 104.212; 95% CI, 11.399-952.757; p＜0.001).Conclusions: Our study indicated that HFNC was an effective way of respiratory support in the treatment of severe COVID-19. The ROX index greater than 6.10 at 24 h after initiating HFNC was a good predictor of successful HFNC treatment.

Dysregulation of Immune Response in Patients with COVID-19 in Wuhan, China (preprint)

Background: In December 2019, a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in Wuhan and rapidly spread throughout China. The immune response is likely to be highly involved in the pathological process of coronavirus disease 2019 (COVID-19). However, information on specific changes of immune response in COVID-19 are limited. Methods: Demographic and clinical data of all confirmed cases with COVID-19 on admission at Tongji Hospital from January 10 to February 12, 2020, were collected and analyzed. The expression of lymphocytes, lymphocyte subsets, infection related biomarkers and inflammatory cytokines were analyzed and compared between severe cases and non-severe patients. Findings: Of the 452 patients with COVID-19 recruited from January 10 to February 12, 2020, 286 were diagnosed as severe infection. The median age was 58 years and 235 were male. 201 patients had chronic diseases and a higher percentage in the severe cases. The most common symptoms were fever, shortness of breath, expectoration, and fatigue. Severe cases tend to have higher white blood cell and neutrophil lymphopenia ratio (NLR), as well as lower percentages of monocytes, eosinophils, and basophils. Most of severe cases demonstrated elevated levels of infection-related biomarkers, and inflammatory cytokines. The numbers of B cells, T cells and NK cells was significantly decreased in patients with COVID-19, and more severely decreased in the severe cases. T cells were shown to be most affected by SARS-CoV-2, and more hampered in severe cases. Both helper T cells and suppressor T cells in patients with COVID-19 were below normal levels. Helper T cells tend to be more affected in severe cases. The percentage of naïve helper T cells increased and memory helper T cells decreased in severe cases. Patients with COVID-19 have lower level of regulatory T cells, and more obviously damaged in severe cases. Interpretation: SARS-CoV-2 might mainly act on lymphocytes, especially T lymphocytes, and induce a cytokine storm in the body, generate a series of immune responses. Surveillance of NLR and lymphocyte subsets is helpful in the early screening of critical illness, diagnosis and treatment of COVID-19.Funding Statement: None.Declaration of Interests: All authors declare no competing interests.Ethics Approval Statement: The study was performed in accordance with Tongji Hospital Ethics Committee (IRB ID: TJ-C20200121). Written informed consent was waived by the Ethics Commission of the designated hospital for emerging infectious disease.

Dysregulation of immune response in patients with COVID-19 in Wuhan, China ;Clinical Infectious Diseases ;Oxford Academic

Abstract Background In December 2019, coronavirus disease 2019 (COVID-19) emerged in Wuhan and rapidly spread throughout China. Methods Demographic and clinical data of all confirmed cases with COVID-19 on admission at Tongji Hospital from January 10 to February 12, 2020, were collected and analyzed. The data of laboratory examinations, including peripheral lymphocyte subsets, were analyzed and compared between severe and non-severe patients. Results Of the 452 patients with COVID-19 recruited, 286 were diagnosed as severe infection. The median age was 58 years and 235 were male. The most common symptoms were fever, shortness of breath, expectoration, fatigue, dry cough and myalgia. Severe cases tend to have lower lymphocytes counts, higher leukocytes counts and neutrophil-lymphocyte-ratio (NLR), as well as lower percentages of monocytes, eosinophils, and basophils. Most of severe cases demonstrated elevated levels of infection-related biomarkers and inflammatory cytokines. The number of T cells significantly decreased, and more hampered in severe cases. Both helper T cells and suppressor T cells in patients with COVID-19 were below normal levels, and lower level of helper T cells in severe group. The percentage of naïve helper T cells increased and memory helper T cells decreased in severe cases. Patients with COVID-19 also have lower level of regulatory T cells, and more obviously damaged in severe cases. Conclusions The novel coronavirus might mainly act on lymphocytes, especially T lymphocytes. Surveillance of NLR and lymphocyte subsets is helpful in the early screening of critical illness, diagnosis and treatment of COVID-19.