Effectiveness and safety of a new helmet CPAP configuration allowing tidal volume monitoring in patients with COVID-19

BACKGROUND: High generated tidal volumes (V(t)) have been correlated with higher risk of self-induced lung injury and worse clinical outcome. This study aimed to evaluate the effectiveness and safety of a new helmet continuous positive airway pressure delivered (h-CPAP) configuration allowing V(t) monitoring in patients affected by COVID-19. METHODS: This prospective observational study was performed in the respiratory intermediate care unit of University Hospital in Turin, Italy, between March 24th, and June 15th, 2020. Included patients were treated with CPAP via a single-limb intentional leak configuration by a turbine-driven ventilator, provided with a dedicated patch. Effectiveness and safety of the configuration and healthcare workers safety were the outcomes of the study. MAIN FINDINGS: Thirty-five patients were included in this study. Median age was 67 years (IQR 57–76 years), and 30 patients (85.7%) were men. Median value of overall leaks (intentional plus unintentional) was 68 L/min (IQR 63–75). Reliability of V(t) measurements was 100%. An out of scale of V(t) (above 50% compared to the previous values) was never recorded. Six patients (17.1%) needed more than two helmet replacements, due to leak test >10 l/min. Arm oedema and skin breakdowns were reported in sixteen (45.7%) and seven (20%) patients respectively. Among the 63 healthcare workers involved in the care of COVID-19 patients during the study only one was positive at RT-PCR nasopharyngeal swab testing. CONCLUSIONS: The use of h-CPAP for treating COVID-19 in this configuration allowed for reliable V(t) monitoring. Further studies evaluating this configuration in larger patients’ cohorts are needed.