Clinical characteristics of COVID-19 patients who received ventilator management during the omicron variant period in a tertiary hospital in Japan

Background: Severe COVID-19 patients who received ventilator management were not very rare even when the omicron variant became dominant, but the clinical characteristics of these patients are still unclear. Methods: The clinical characteristics of severe COVID-19 patients requiring ventilator management were retrospectively investigated from January 2023 to December 2023. Results: Severe COVID-19 patients who received ventilator management accounted for 11 of 275 (4.2%) patients during the omicron variant period. Their mean age was 70.7 (51-85) years, and males were predominant. Ten of eleven (91.7%) patients were managed in the emergency department and had underlying diseases, including chronic lung/heart/kidney diseases and neurological diseases. However, only 4 of 11 (36.4%) had a clear history of vaccination. The patients showed a positive SARS-CoV-2 antigen titer of 3305.7 (12.9-20912). All 11 patients were treated with remdesivir and dexamethasone, and 5 (45.5%) also received sotrovimab. Pathogenic bacteria were isolated from 7 of 11 (63.6%) patients, and all 11 patients were treated with antibiotics. Only 3 of 11 (27.3%) patients were managed using extracorporeal membrane oxygenation (ECMO), but 9 of 11(81.8%) patients survived. Conclusions: These data suggest that severe COVID-19 patients who required ventilator management were less-vaccinated, elderly patients with underlying disease. These patients were treated successfully using antiviral agents, steroids, neutralizing antibodies, and antibiotics, with a few also treated using ECMO in the omicron era.