How are the parameters from the Blood Pressure module calculated?

The formulas used to calculate each parameter available in the Blood Pressure add-on for LabChart can be found in LabChart's help documentation under Blood Pressure > Blood Pressure Parameters. The list of parameters and their calculation methods are below:

 

Ventricular Parameters

· Max Pressure: The maximum pressure during the cycle.
· Min Pressure: The minimum pressure during the cycle.
· Mean Pressure: The arithmetic mean pressure in the current cycle.
· Max-Min Pressure: The difference between minimum and maximum pressures.
· Heart Rate: Calculated as 60 / (Cycle Duration).
· Max dP/dt: The steepest slope during the upstroke of the pressure curve.
· Min dP/dt: The steepest slope during the downstroke of the pressure curve.
· EDP: Pressure at the end of diastole.
· Systolic Duration: Elapsed time between the start of the cycle (at EDP) and the time of Min dP/dt.
· Diastolic Duration: Elapsed time between the time of Min dP/dt and the end of the cycle.
· Cycle Duration: Elapsed time between two alignment points.
· Tau: The exponential time constant of relaxation.
· Pressure Time Index: Also known as tension–time index. The average ventricular pressure during systole, multiplied by the systolic duration.
· Contractility Index: Max dP/dt divided by the pressure (P) at the time of Max dP/dt.
· IRP Average dP/dt: The slope of a straight line fitted to the pressure over the Isovolumic Relaxation Period used for estimation of tau.

Arterial Parameters

· Systolic Pressure: The maximum pressure during the cycle.
· Diastolic Pressure: The pressure at the start of the cycle.
· Dicrotic Notch Pressure: Pressure at the time of the dicrotic notch (if detected).
· Mean Pressure: The arithmetic mean pressure in the current cycle.
· Pulse Pressure: The difference between diastolic and systolic.
· Ejection Duration: Elapsed time between the start of cycle and the dicrotic notch (if detected).
· Non-Ejection Duration: Elapsed time between the dicrotic notch (if detected) and the end of cycle.
· Cycle Duration: Elapsed time between two alignment points.
· Heart Rate: 60 / (Cycle Duration).
· Time to Peak: Elapsed time between the start of the cycle and time of systolic pressure.
· Mean Diastolic Pressure: The average pressure between the dicrotic notch (if detected) and the end of cycle.
 

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