Characteristics, outcomes and global trends of respiratory support in patients hospitalized with COVID-19 pneumonia: a scoping review.

INTRODUCTION: To date, a shared international consensus on treatment of Coronavirus disease 2019 (COVID-19) with invasive or non-invasive respiratory support is lacking. Patients' management and outcomes, especially in severe and critical cases, can vary depending on regional standard operating procedures and local guidance. EVIDENCE ACQUISITION: Rapid review methodology was applied to include all the studies published on PubMed and Embase between December 15th, 2019 and February 28th, 2021, reporting in-hospital and respiratory support-related mortality in adult patients hospitalized with COVID-19 that underwent either continuous positive airway pressure (CPAP), non-invasive ventilation (NIV) or invasive mechanical ventilation (IMV). Only English language studies with ≥100 patients and reporting data on respiratory failure were included. Data on comorbidities, ventilatory parameters and hospital-related complications were registered. EVIDENCE SYNTHESIS: Fifty-two studies (287,359 patients; 57.5% males, mean age 64 years, range 24-98 years) from 17 different countries were included in the final analysis. 33.3% of patients were hospitalized in intensive care units. 44.2% had hypertension, 26.1% had diabetes, and 7.1% a chronic respiratory disease. 55% of patients underwent respiratory support (36% IMV, 62% NIV and 2% CPAP). Without considering a study with the highest number of patients treated with NIV (N.=96,729), prevalence of NIV and CPAP use was 12.5% and 13.5% respectively. Globally, invasive and non-invasive approaches were heterogeneously applied. In-hospital mortality was 33.7%, and IMV-related mortality was 72.6% (range: 4.3-99%). Specific mortality in patients treated with CPAP or NIV was available for 53% of studies, and was 29% (range: 7.2-100%). The median length of hospital stay was 13 days (range: 6-63). The most frequent hospital-related complication was acute kidney injury being reported in up to 55.7% of enrolled patients. CONCLUSIONS: Global employment of respiratory supports and related outcomes are very heterogeneous. The most frequent respiratory support in patients with COVID-19 pneumonia is IMV, while NIV and CPAP are less frequently and equally applied, the latter especially in Europe, while data on NIV/CPAP-related mortality is often under-reported. Integrated and comprehensive reporting is desirable and needed to construct evidence-based recommendations.

Severity of respiratory failure at admission and in-hospital mortality in patients with COVID-19: a prospective observational multicentre study.

OBJECTIVES: COVID-19 causes lung parenchymal and endothelial damage that lead to hypoxic acute respiratory failure (hARF). The influence of hARF severity on patients' outcomes is still poorly understood. DESIGN: Observational, prospective, multicentre study. SETTING: Three academic hospitals in Milan (Italy) involving three respiratory high dependency units and three general wards. PARTICIPANTS: Consecutive adult hospitalised patients with a virologically confirmed diagnosis of COVID-19. Patients aged <18 years or unable to provide informed consent were excluded. INTERVENTIONS: Anthropometrical, clinical characteristics and blood biomarkers were assessed within the first 24 hours from admission. hARF was graded as follows: severe (partial pressure of oxygen to fraction of inspired oxygen ratio (PaO2/FiO2) <100 mm Hg); moderate (PaO2/FiO2 101-200 mm Hg); mild (PaO2/FiO2 201-300 mm Hg) and normal (PaO2/FiO2 >300 mm Hg). PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the assessment of clinical characteristics and in-hospital mortality based on the severity of respiratory failure. Secondary outcomes were intubation rate and application of continuous positive airway pressure during hospital stay. RESULTS: 412 patients were enrolled (280 males, 68%). Median (IQR) age was 66 (55-76) years with a PaO2/FiO2 at admission of 262 (140-343) mm Hg. 50.2% had a cardiovascular disease. Prevalence of mild, moderate and severe hARF was 24.4%, 21.9% and 15.5%, respectively. In-hospital mortality proportionally increased with increasing impairment of gas exchange (p<0.001). The only independent risk factors for mortality were age ≥65 years (HR 3.41; 95% CI 2.00 to 5.78, p<0.0001), PaO2/FiO2 ratio ≤200 mm Hg (HR 3.57; 95% CI 2.20 to 5.77, p<0.0001) and respiratory failure at admission (HR 3.58; 95% CI 1.05 to 12.18, p=0.04). CONCLUSIONS: A moderate-to-severe impairment in PaO2/FiO2 was independently associated with a threefold increase in risk of in-hospital mortality. Severity of respiratory failure is useful to identify patients at higher risk of mortality. TRIAL REGISTRATION NUMBER: NCT04307459.