Figure 1.
Crude and adjusted proportions of high-flow nasal cannula (HFNC) failure by to-date duration of use. Failure of HFNC is a composite outcome of either initiation of invasive mechanical ventilation or death without mechanical ventilation by Study Day 28. (A) Shows the crude risk of failure in the whole population, according to increasingly longer durations of respiratory support with HFNC, with the minimal duration of exposure and the number of patients in each nested cohort represented on the x-axis. (B) Shows the adjusted probability of HFNC failure by to-date duration of use. Point estimates of failure are based on regression modeling adjusted for age, sex, body mass index, respiratory rate, and SpO2 at time of study enrollment, and the number of comorbidities, with 95% confidence intervals denoted by the error bars. SpO2 = peripheral arterial oxygen saturation.