The bottom trace, of these original records, depicts the pressure in the congestion cuffs (Pcuff), whereas the top trace represents the volume change. A, in the pressure protocol of Study I first a series of 10 mmHg pressure steps was applied. After intermediate reduction of Pcuff to 30 mmHg the congestion cuff was then re-inflated using cumulative pressure steps of 3 mmHg. B, in Study II the order of the pressure protocols was inverted and the 3 mmHg pressure steps were applied in the first phase of the VCP protocol.