“…We compared the following covariates between the early and non-early tracheostomy groups: age [30]; sex; body mass index (kg/m 2 ); Japan Coma Scale status at admission [31]; Charlson comorbidity index score [2,4,32]; chronic pulmonary disease as a comorbidity at admission [5,7]; pneumonia (ICD-10 code J10-J18 or J69) as a complication at admission [6]; hyponatremia (ICD-10 codes E222 and E871) as a complication at admission [33,34]; neurological presentation at admission (bulbar palsy [ICD-10 codes G12, G521, G522, G523, R13, and R47] and autonomic dysfunction [ICD-10 codes G90, H570, I10, I49, I95, K56, K59, L74, N39, R00, R15, R32, R33, R39, and R61]) [35,36]; ambulance use; referral from other hospitals; treatment year [1][2][3][4]; number of days from hospital admission to MV initiation [6]; ICU admission until the day of MV initiation; treatments until the day of MV initiation [procedures and monitoring (invasive arterial pressure monitoring, central venous catheter insertion, CO 2 monitoring, deep vein thrombosis prophylaxis, and chest compression and/or defibrillation), medical treatments (vasopressors, intravenous antihypertensive drugs, antiarrhythmic drugs, insulin, antiulcer drugs, antibiotic drugs, heparin, and enteral nutrition), and starting immunotherapy (plasma exchange, intravenous immunoglobulin (IVIg), intravenous corticosteroids, and none)].…”