All of the parameter assignments in the working parameter file may be updated as waveforms are being calculated and displayed on-line except those labelled with {*}. Any updates to these parameters will be ignored. As soon as any parameter (not labelled with {*}) is updated in the working parameter file, the file is saved (with a new name) in order to document fully the simulation (see Section 5.1). Some caveats to on-line parameter updating are provided below.
Since none of the display parameters are labelled with a {*}, they are permitted to be updated on-line. Thus, the researcher may, for example, change the waveforms that he is currently viewing without having to rerun rcvsim. However, when the working parameter file is updated only through the display parameters, the update will not be documented to file.
Updates to the working parameter file are also not documented when the particular update is not relevant to the status of the current simulation. For example, an update to the Cls parameter is relevant when the intact circulation and heart-lung unit preparations are being implemented. Thus, in this case, the update will be documented to file. However, when the systemic circulation preparation is being executed, an update to the Cls parameter is irrelevant (see Figure 3) and is thus not documented to file.
When implementing the heart-lung unit, the Pv and Pa parameters may be updated on-line provided that they are not being adjusted through the Pvs and Pas parameters, respectively. Otherwise, the on-line adjustment of the Pv and Pa parameters will be ignored. Similarly, when implementing the systemic circulation preparation, any update to the Crd parameter will be ignored unless it is not being adjusted through the Crds parameter.
As described in Section 3.1, the volume in each of the capacitive elements of the pulsatile heart and circulation (any preparation) is always conserved through a pressure adjustment. The only exception to this rule is naturally when the researcher desires to adjust total blood volume through the Qtot parameter (which is only applicable to the intact pulsatile heart and circulation preparation). In this case, the volume is added to or subtracted from the systemic venous volume and the systemic venous pressure is adjusted accordingly.
The instantaneous lung volume waveform may only be altered by updating the following parameters: Tr, Qt, Qfrs, and Qds. If parameters of the ventilatory model in Figure 6 are updated (which includes the Pvc parameter), the value of intrathoracic pressure at the functional reserve volume of the lungs will be adjusted instantaneously in order to preclude any change to instantaneous lung volume.
Finally, when updating the adjustable parameters of the pulsatile heart and circulation through the F, Ra, Qvo, Crs, and Cls parameters, the current values and the setpoint values of these parameters will be adjusted. Note that updates to the Crs and Cls parameters will take effect at the start of the subsequent ventricular contraction.