Inspiratory flow rate and ventilation distribution

In normal erect subjects inspiring from functional residual capacity (FRC), it would appear that the effect of flow rate on ventilation distribution is predominantly in the early stages of inspiration. During tidal breathing, this suggests that the distribution of expired alveolar gas in the trachea and upper airways differs from the air inspired subsequently. The change in gas distribution at higher flow rates may reflect the increasing importance of regional airways conductances; on the other hand regional inequalities of ΔP are probably also playing a part.