Clinical characteristics and outcomes of critically ill COVID-19 patients in Tokyo: a single-center observational study from the first wave.

BACKGROUND: Many studies have been published about critically ill coronavirus disease 2019 (COVID-19) during the early phases of the pandemic but the characteristic or survival of critically ill Japanese patients have not yet been investigated. We sought to investigate the characteristics, inflammatory laboratory finding trends, and outcomes among critically ill Japanese patients who were admitted to the intensive care unit (ICU) with the first wave of COVID-19. METHODS: A retrospective observational study was performed in a single institution in the center of Tokyo. Laboratory-confirmed COVID-19 patients admitted to the ICU from March 19 to April 30, 2020 were included. Trends for significant inflammatory laboratory findings were analyzed. In-hospital death, days of mechanical ventilation or oxygen supplementation, days of ICU or hospital stay were followed until May 26, 2020. RESULTS: Twenty-four patients were included. Median age was 57.5 years, and 79% were male. The neutrophil-to-lymphocyte ratio was elevated to a median of 10.1 on admission and peaked on Day 10 of illness. Seventeen patients were intubated on Day 11 of illness and received mechanical ventilation. One patient underwent extracorporeal membrane oxygenation. The majority (88%) received systemic steroids, including 16 patients who received high dose methylprednisolone (500-1000 mg). Favipiravir was used in 38% of patients. Two patients, including 1 who refused intensive care, died. Eighteen patients were discharged. Median length of ICU and hospital stay for all patients was 6 and 22 days, respectively. Median length of ventilator dependency was 7 days. Four patients underwent a tracheostomy and received prolonged ventilation for more than 21 days. One patient receiving mechanical ventilation died. All survivors discontinued ventilator use. CONCLUSIONS: Mortality was remarkably low in our single institutional study. Three survivors received mechanical ventilation for more than 3 weeks. Trends of clinically significant laboratory markers reflected the clinical course of COVID-19.