Question special

Looking at the baseline characteristics of the 2 groups, it appears that there are similar levels of a respiratory comorbidity in both populations. However, the intervention group had a higher # of patients whose primary diagnosis at admission was respiratory failure (38.5% vs 31.5%). While all patients on a mechanical ventilator will have reduced mucociliary transport, those with a primary respiratory illness as reason for admission (and presumably primary indication for mechanical ventilation) would have worsened mucociliary function. As one of the hypothesized benefits of high-flow is enhanced mucociliary transport, I wonder if the greater time spent with high-flow in the intervention group would have a more significant impact in this specific patient population?