Rapid chest compression and flow limitation.

6. It has been demonstrated that control over volume history reduces the intrasubject variability of flow measurements by RCT [6]. It is possible that the breath-stacking technique reduced the scatter of the flow data. This remains unclear because coefficients of variation of repeated measurements are not reported. All these factors allow forced expiratory flows to differ among different manoeuvres even when wave speed (flow-limitation) conditions are achieved by each technique, and could explain the reported flow differences. Unfortunately, this study cannot resolve the ongoing flowlimitation debate in RCT, but demonstrates that standardization of forced expiratory manoeuvres is essential for flow comparison; a fact well-known in adult lung function laboratories.