Background: Oxygen therapy (OT) is the most widely used supportive regime in patients with hypoxemic acute respiratory failure (ARF) due to severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection. The aim of this study was to identify the effect of noninvasive ventilation support on coronavirus disease 2019 (COVID-19) patients and risk factors for invasive mechanical ventilation (IMV).
Methods: We retrospectively analyzed confirmed COVID-19 subjects from nine hospitals outside Wuhan. All hospitalized patients who tested positive for COVID-19 by real-time polymerase chain reaction between January 1st and March 31st, 2020, were recruited. The patients were divided into four groups based on the most advanced OT regime, including no OT, nasal oxygen therapy, high-flow nasal oxygen therapy (HFNOT) or noninvasive ventilation (NIV), and IMV. Multiple logistic regression models were performed to determine risk factors for IMV.
Results: Of the 683 recruited subjects, 315 (46.1%) subjects did not need OT, 300 (43.9%) received nasal oxygen therapy, 51 (7.5%) received HFNOT or NIV, while 17 (2.5%) subjects had to be intubated. The lactate in the OT group was higher than in the no OT group (2.7 vs 1.6, P = 0.02). In addition, HFNOT or NIV patients had a higher respiratory rate, but a lower PaO2 (P < 0.001). HFNOT and NIV had an obvious beneficial effect on ARF with 75% of COVID-19 patients recovering from respiratory failure. Patients with IMV were older (P < 0.001), had a higher rate of hypertension (P < 0.001) and more secondary bacterial infections (P < 0.001) compared to those without intubation. The multivariate model showed that secondary bacterial infection (OR = 6.87, P = 0.009) was independently associated with IMV failure among COVID-19 patients.
Conclusion: We identified that HFNOT and NIV had an obvious beneficial effect on ARF among COVID-19 patients. We also demonstrated that secondary bacterial infection was an independent risk factor for NIV failure in patients infected by SARS-COV2.
Keywords: COVID-19, SARS-CoV-2, oxygen therapy, invasive mechanical ventilation