Risk Factors of Transfer to Mechanical Ventilation of COVID-19 Patients in a Retrospective Non-Randomized Study

ABSTRACT

Background. The COVID-19 pandemic is associated with significant number of complications and mortality and a burden on the healthcare system. In 10–15% of hospitalized patients, the invasive and non-invasive mechanical ventilation (IMV/NIMV) is required. At the same time, it is important to stratify the risk of mechanical ventilation upon admission to the hospital. Aims — to identify clinical and laboratory risk factors for transfer to IMV and NIMV in hospitalized patients with COVID-19-associated pneumonia. Methods. A retrospective one-center nonrandomized study of 386 consecutive hospitalized patients with COVID-19-associated pneumonia was performed. The primary endpoints were IMV (n = 22) and NIMV (n = 28). Risk factors of artificial ventilation were considered for periods up to 14 and 28 days for both variants. To select a risk predictor, a univariate analysis based on Cox survival regression was performed, followed by multivariate analysis to determine risk factors at these time points. Results. After 28 days from admission the mortal exit was registered in 20 patients from 386 patients (5.2%). 22 patients (5.7%) were transferred to IMV, and 28 patients (7.3%) — to NIV, and 9 of the latter were transferred later to IMV. As a result of univariate and multivariate analyzes, the risk factors for transfer to mechanical ventilation on 14th day were age > 65 years (OR = 5.91), a history of stroke (OR = 17.04), an increased serum level of urea (OR = 6.36), LDH (OR = 7.39), decreased sodium (OR = 12.32), GFR < 80 mL/min/1.73 m2 (OR = 13.75) and platelets (OR = 4.14);on the 28th day — age > 65 years (OR = 4.58), J-wave on the ECG (OR = 2.98), an increase of LDH (OR = 9.99) and a decrease in albumin (OR = 2.77) in serum. Predictors of the transfer of patients with COVID-19 to NIV within the period up to 14 days from the beginning of hospitalization were the age > 65 years (OR = 5.09), procalcitonin level in the blood > 0.25 ng/ml (OR = 0.19), leukocytes > 11×109 (OR = 19.64) and increased LDH (OR = 3.9). Conclusions. In patients with COVID-19, the risk factors for transfer to IMV/NIVL in the period of 14 and 28 days from the beginning of hospitalization were identified, which enable patient’s mechanical ventilation stratification and to plan respiratory support resources.