MPVS-400 Quick Start
M.I. P/N:004-2149 Rev. B
16.
Configure the Chart software according to user preferences (please refer to the ADInstruments user’s
manual(s) for more details). The PVAN CD contains a suggested Chart data acquisition interface to help
investigators understand how to utilize the Chart software to record P-V data from the MPVS-400.
17.
Calibration Setup
: Follow the instructions in the ADInstruments Chart user’s manual(s) as well as Millar’s
PVAN user’s guide to perform two-point calibration procedures for both the pressure and volume
channels. For simplified electronic calibration verification, use the transducer/calibration controls on the
front of the MPVS-400 to provide fixed voltage signal references for pressure (0, 25, 100 mmHg) and
volume (5, 25, 50 RVU) that may be used to quickly perform the two-point calibration procedure.
Remember that RVU verification is only for Relative Volume Units, not absolute volume. Conversion of
Relative Volume Units into true volume units requires additional steps (please refer to Millar’s PVAN
user’s guide for additional instructions regarding volume calibration techniques). Volume calibration for a
given catheter may be performed using small tubes of known diameters (a calibration cuvette, which can
be supplied by Millar Instruments) filled with fresh, slightly heparinized blood drawn from an
experimental subject. Validation of the volume estimates provided by the Millar hardware can be
performed by other means, e.g. by thermodilution, flow probes, hypertonic saline dilution, echo, etc.
18.
Pressure Transducer Balancing:
After the catheter tip has soaked for at least 30 minutes, set the Pressure
Transducer/Calibration switch on the front panel of the MPVS-400 to Transducer. Unlock and adjust the
Balance control knob for the pressure channel the catheter is connected to. Use the Balance control knob
to adjust the pressure transducer output while dipping the transducer just below the surface of sterile
water or saline (essentially a zero pressure environment). Adjust the Balance control knob until the output
signal reads approximately 0 mmHg (as displayed by an indicator in the data acquisition software or
similar monitor) then lock the knob into position. Repeat the procedure if an additional pressure
transducer is connected to the MPVS-400. Pressure calibration may be verified using an external
manometer (digital or mercury).
For best stability and zero adjustment, shield the sensor from bright ambient light during the balancing
procedure and allow the catheter-tip to soak in body temperature sterile water or saline for 30 minutes
prior to insertion into the biological environment. Zero balancing of the pressure transducer should be
done prior to each catheterization procedure.
19.
The system is now ready to begin conducting P-V experiments. Prepare the experimental subject for
catheter insertion according to the lab’s established experimental protocols. When the experimental
subject is ready, insert the catheter into the left ventricle and begin acquiring and recording P-V data
[Please Note: Millar Instruments recommends a data acquisition sampling rate of 1 kHz (1000
samples/second) in order to accurately capture all of the features of the P-V waveforms
produced by the fast beating hearts of mice and rats]
. To ensure activation of the catheter tip
transducers, make sure that both the Pressure Transducer/Calibration Switch and Volume
Transducer/Relative Volume Units (RVU) Calibration Switch on the front panel of the MPVS-400 are
switched away from the calibration reference settings and are set to Transducer. Please refer to the
ADInstruments Chart software guide for additional details on operating the data acquisition software.
After the P-V data has been collected, please refer to the PVAN software user’s guide for instructions on
how to export P-V data selections out of the Chart software to perform a comprehensive data analysis in
PVAN.
20.
When necessary, clean the MPVS-400 hardware with a cloth and isopropyl alcohol or water. Do not allow
liquids to enter the chassis as this will damage the sensitive electronics housed inside. Air vents may be
cleaned with suction (i.e. a vacuum cleaner). The MPVS-400 hardware has not been tested for
compatibility with any method of sterilization.
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