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The MLS340/6 Cardiac Output Module for
Windows provides the user with an analysis tool to easily
extract and calculate cardiac output from small animals,
using the thermodilution technique and recorded in LabChart.
The Cardiac Output Module should be used with the latest version of LabChart. Click here for the latest LabChart Update for Windows.
The module calculates:
- cardiac output in mL/min
- baseline temperature
- area under the thermodilution curve
- baseline slope correction
It also adds values to the Data Pad from which data can be exported to other applications.
The module includes three main dialog windows:
- Cardiac Output Window
- Cardiac Output Settings
- Set Baseline Correction
Cardiac Output Window
A thermodilution curve showing baseline determination (red line) and calculated exponential curve
(shaded region) and cardiac output values (top right-hand corner).Cardiac Output Settings
The Cardiac Output Settings dialog box allows the user to define the parameters used in the calculation of cardiac output.
The injectate parameters that can be entered include Temperature (0 to 30 °C), Volume (0.01 to 50mLs)
A Correction factor option has been included in the settings for the user to account for warming of the injectate as it is injected through the catheter or any other correction factor related to the experimental setup/conditions.
Depending on the injectate temperature, there may be some permanent cooling
of the blood. As the cold/cooled fluid is recirculated the
thermodilution curve does not return to its baseline value.
The Tail fitting range allows the user to define a portion
of the downslope of the recorded thermodilution curve from
which an exponential curve is calculated and extrapolated to
a baseline. The portion of the downslope used in this calculation
is specified as a percentage of the curve full height.
The baseline temperature is important in calculating CO and is calculated for each thermodilution curve created and analyzed.
The user
in selecting the curve is also required to define a period
of time prior to the thermodilution curve for the module to
determine baseline temperature. Two parameters are required
from the user:
- The Onset time defines the period of time there is beginning to be a temperature change (the data in this period will not be used for the baseline calculation).
- The user sets the time interval for baseline temperature determination in the Calculate baseline from text box. The module will calculate the baseline over this time interval, with the period selected ending at the start of the onset period (see Cardiac Output window above).
Set Baseline Correction
Any baseline drift can also be corrected by selecting baseline data and choosing Set Baseline Correction from the Cardiac Output menu. Selecting OK will automatically insert the correction factor in the CO calculation, or it can be turned on or off in the Settings dialog box by checking or unchecking the Baseline slope correction text box.
The capture option in the Setting dialog box allows the user to mark the selected thermodilution curve with the CO values as well as automatically adding the calculated values for each thermodilution curve to the Data Pad.
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