Potential Predictors of Poor Prognosis among Critical COVID-19 Pneumonia Patients Requiring Tracheal Intubation

Coronavirus disease 2019 (COVID-19) is a global public health concern that can be classified as mild, moderate, severe, or critical, based on disease severity. Since the identification of critical patients is crucial for developing effective management strategies, we evaluated clinical characteristics, laboratory data, treatment provided, and oxygenation to identify potential predictors of mortality among critical COVID-19 pneumonia patients. We retrospectively utilized data from seven critical patients who were admitted to our hospital during April 2020 and required mechanical ventilation. The primary endpoint was to clarify potential predictor of mortality. All patients were older than 70 years, five were men, six had hypertension, and three ultimately died. Compared with survivors, non-survivors tended to be never smokers (0 pack-years vs. 30 pack-years, p = 0.08), to have higher body mass index (31.3 kg/m(2) vs. 25.3 kg/m(2), p = 0.06), to require earlier tracheal intubation after symptom onset (2.7 days vs. 5.5 days, p = 0.07), and had fewer lymphocytes on admission (339 /mu L vs. 518 /mu L, p = 0.05). During the first week after tracheal intubation, non-survivors displayed lower values for minimum ratio of the partial pressure of oxygen to fractional inspiratory oxygen concentration (P/F ratio) (44 mmHg vs. 122 mmHg, p < 0.01) and poor response to intensive therapy compared with survivors. In summary, we show that obesity and lymphopenia could predict the severity of COVID-19 pneumonia and that the trend of lower P/F ratio during the first week of mechanical ventilation could provide useful prognostic information.