The Alpha Calibration is an optional calibration step performed after the cuvette and saline calibration steps, which will match the PV-Loop module's calculated values to a reference source. You can calculate the alpha coefficient of Baan's equation by dividing the cardiac output (CO) or stroke volume (SV) recorded by the PV Loop Module by CO or SV measurements from another source such as aortic flow probes, echocardiography, magnetic resonance imaging, or angiograms.
To calculate and apply an Alpha Calibration, first record PV data into LabChart's PV Loop Module
. Calibrate the volume using both a cuvette calibration and saline calibration. Select representative baseline data and perform a PV Loop Analysis using the Analyze option from the PV Loop menu.
Open the Hemodynamics Table and locate the Stroke Volume or Cardiac Output column. Find the Average value (shown on the lower portion of the table) and enter this value into the Alpha Calibration top line labeled [Millar]. The bottom line, labeled [Ref] should be taken by the reference measurement source. The alpha coefficient will be automatically calculated, and this value can be applied to your data by clicking the "Apply Alpha Calibration" box.