Low Dose Whole Lung Radiation Therapy for Patients With COVID-19 and Respiratory Compromise

The primary outcome is the mortality rate 30 days after the ICU-based mechanical ventilation initiation.Based on current data available, the mortality rate for ventilated patients is assumed to be 80% in the current design. An interim futility analysis will be conducted after 16 evaluable patients have received the ultralow dose-whole lung radiation therapy (ULD-WLRT). If at least 3 patients survive for at least 30 days, we will enroll additional 8 patients (total of 24 patients). Otherwise, the trial will stop for further evaluation. Due to the limited data currently available in local institutions about a 30 day mortality rate , we will retrospectively evaluate the mortality rate of the ventilated patients without the ULD-WLRT in our institution when data is available. Time to event secondary objectives (e.g. overall survival, time to discharge) analyses will be performed using Kaplan-Meier survival analysis, with a competing risk model (leaving the study because of death), including effects for demographic/clinical characteristics in the model. Proportional endpoints (such as % patients off ventilator) will be calculated along with the 95% Clopper-Pearson exact confidence interval. Pre/post measurements will be evaluated using linear mixed models for repeated measures (with proper data transformation as needed). Association between demographic/clinical characteristics and other secondary objectives (size of ground glass opacities (GGO)/opacification, for example) will be accomplished with generalized linear models.