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Millar MPVS Ultra User Manual

Signal conditioning hardware pressure-volume loop system
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MPVS Ultra
Signal Conditioning
Hardware
User Guide
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Summary of Contents for Millar MPVS Ultra

  • Page 1 MPVS Ultra Signal Conditioning Hardware User Guide...

  • Page 2: Table Of Contents

    The MPVS Ultra can be used on animals as small as transgenic mice and as large as full grown horses. Using the MPVS Ultra, cardiovascular pressure and volume signals can be...
  • Page 3 The MPVS Ultra also measures high fidelity pressure signals using a Millar catheter. The solid-state pressure sensor uses the same technology found in Millar’s extensive line of ®...

  • Page 4: Getting Started

    Connect the MPVS Ultra hardware to your computer before turning it on. The first time that a computer is connected to an MPVS Ultra system, software drivers will be installed; this installation will not be necessary after the first installation.
  • Page 5 MPVS Ultra to the pressure sensor bridge as well as the pressure signal back to the MPVS Ultra. When the system is used to record the internal ECG (IECG), the signal is measured from the catheter through the P-V cable.
  • Page 6 As shown below, the MPVS Ultra connects easily to the ADInstruments PowerLab16/30 using the MPVS Ultra – PowerLab cable pack. The cable pack is a set of thirteen BNC-to- BNC cables specifically sized for connecting these two systems. Ten 9-inch cables are included for connecting the first ten channels on the MPVS Ultra to the first ten channels of the PowerLab system.
  • Page 7 Cable Length Use the shortest cables and cords that will serve the purpose. Millar offers 4-foot input cables for users whose subjects will be located close to the hardware. BNC-to-BNC cables are available in shorter lengths for those who can use them. See the “ADInstruments PowerLab Setup”...

  • Page 8: Normal Operation

    Perform this step before volume signal calibration if data will be recorded in volume units. Plug the cuvette cable into the MPVS Ultra. In the Control Interface Rho Cuvette tab, select the appropriate settings. Perform the following with as little delay as possible: Dry the cuvette’s well with a gauze or swab.
  • Page 9 5. Alpha correction If stroke volume comparison for alpha correction will be used, this may be done at any point according to the protocol. If raw data will be recorded as volume units (ml or μl), alpha calculation should be performed before the final volume calibration. Recalibrate the volume signal channels now if alpha is used.
  • Page 10 A representative animal is typically required due to the volume of blood removed. Plug the cuvette cable into the MPVS Ultra. In the Control Interface Rho Cuvette tab, select the appropriate settings. Perform the following with as little delay as possible. Dry the cuvette’s well with a gauze or swab.

  • Page 11: Detailed Operation

    2. Cuvette Input – Rho Calibration Cuvette connects to the MPVS Ultra and provides resistivity value for volume calibration (color-coded gray) 3. ECG Input – External ECG electrodes can be connected to the MPVS Ultra (input color- coded green) and the signal can be displayed real-time ®...
  • Page 12 9. Analog ECG Output – The MPVS Ultra provides an analog ECG channel that will output the ECG measured with the catheter or with an external transducer. Rear Panel 1. USB Control – The MPVS Ultra system is controlled by the MPVS Ultra Control Interface software through a USB connection.

  • Page 13: Catheter Configuration Tab

    Mode. Registration The Registration Menu allows the user to upgrade a MPVS Ultra Single Segment to the full Multi-Segment mode. If the user initially purchased the MPVS Ultra with Multi-Segment capabilities, a keycode will be supplied with the shipment. For information about upgrading a MPVS Ultra Single Segment unit for use with Multi-Segment PV catheters, please contact Customer Service.
  • Page 14 Millar Catheter Selection The Millar Catheter Selection table allows the user to load both standard and custom catheter configurations. This allows the user to configure the hardware for immediate use based on a known catheter model.
  • Page 15 Control Interface. The values can also be saved for use in PVAN Ultra. The MPVS Ultra system can measure resistivity using the rho cuvette (see information regarding the Rho Cuvette tab) or the user can enter a value for resistivity.
  • Page 16 electrode configuration; for example, choosing to use fewer electrodes when measuring a ventricle whose length does not justify the use of all available electrodes. There are four electrode states which can be chosen by the user to configure the catheter to his specification.
  • Page 17 Use this button to delete non-catalog model catheters from the Millar Catheter Selection table. Catalog models cannot be deleted. Power This indicator will be green when the MPVS Ultra hardware is turned on and red when the hardware is turned off. Catheter Detect This indicator will be green when the catheter is successfully passing the primary excitation current through the selected electrodes.

  • Page 18: Catheter Calibration Tab

    5μV/V/mmHg. (See “Theory of Operation – ® Strain Gauge Pressure Transducers.”) The system is designed to use Millar Mikro-Tip pressure transducers with 1000 ohms input impedance and 1000 ohms output impedance. All Millar Mikro-Tip pressure transducers are factory-calibrated to meet these standards.
  • Page 19 The Transducer button must be activated to view pressure waveforms. 0 mmHg – When the 0 mmHg button is activated, the MPVS Ultra will output a zero volt signal to both pressure outputs. 25 mmHg – When the 25 mmHg button is activated, the MPVS Ultra will output a 0.25 V signal to both pressure outputs.
  • Page 20 Catheter Configuration tab. The output shown in the MPVS Ultra Control interface does not account for the volume attributed to parallel conductance of the myocardium. If desired, this correction can be made in the PVAN Ultra software or the user’s acquisition software.

  • Page 21: Rho Cuvette Tab

    The ECG output is scaled at 2V / 1 mV. Notch Filter The MPVS Ultra contains a built-in notch filter on the ECG circuit to remove 50Hz and 60Hz noise. To turn this filter on, select “On” and to turn it off, select “Off”.
  • Page 22 Cuvette button, enter a name for the cuvette configuration (for example, you may choose to use the lot number written on the cable). Enter the K factor for your system. (The gain cannot be changed in this view.) Click OK, then click on the new entry in the Millar Cuvette Selection table.
  • Page 23 2. In the Millar Cuvette Selection field, select the appropriate configuration. By default, the software will use the configuration that was used most recently. The configuration includes both the gain and the K factor. 3. Select the desired units for temperature measurement (°F/°C).
  • Page 24 7. Click on Load to set the displayed resistivity as the value to be used in calibration and measurements. The loaded resistivity value affects the displayed reading and calibration values when displaying volume units. The resistivity value is not temperature corrected; the user is responsible for deciding whether and how to correct for temperature.

  • Page 25: Theory Of Operation

    IV. Theory of Operation The Conductance Method Single Segment Measurement Researchers are able to estimate left-ventricular volume changes via the conductance method using the tiny electrodes built into the catheter tip. A small constant-amplitude AC current is sent out through the distal electrode (E1) to the proximal electrode (E4).

  • Page 26: Dual Field Excitation

    (systole). The wire contains less volume because it has a smaller diameter. Multi-Segment vs. Single-Segment Millar’s multi-segment P-V catheters measure volume using the conductance technique described above. Unlike the single-segment catheter, a multi-segment catheter measures conductance over several electrode segments. The system then sums individual segments’...

  • Page 27: Resistivity - Rho Cuvette

    (the blood in the ventricle) to the volume of the structure. The MPVS Ultra rho cuvette measures resistivity using Baan’s equation, but in a form where the equation has been solved for resistivity. The volume of blood in the cuvette is known –...

  • Page 28: Resistivity - Dip Cuvette

    Relating the resulting readings to the known volumes (typically through a linear regression) allows the user to calibrate measured voltages to volumes. This method is less direct than that employed by the MPVS Ultra system and is not practical for use with multi-segment P-V catheters.

  • Page 29: Additional Guidelines

    USB input and equipotential point. However, these four inputs are not isolated from each other. When using accessories not designed or provided by Millar, the user assumes all responsibility for damage, harm, or loss resulting from the use of these accessories.
  • Page 30 Conductance and conductivity relate to how well a structure or material conducts electrical current. Resistance and resistivity relate to how strongly a structure or material resists the flow of electrical current. Further Reading The Millar, Inc. web site, millar.com, lists published papers. M.I. P/N 004-2163 Rev. C...

  • Page 31: Troubleshooting, System Maintenance And Specifications

    V. Troubleshooting, System Maintenance and Specifications Refer to the MPVS Ultra training CD (001-1058) for more information. Each catheter is delivered with Instructions for Use, complete with care and cleaning instructions. Proper Handling is Critical to Maximizing the Use-Life of Millar's Ultra-miniature P- V Catheters ®...
  • Page 32 Additional guidelines  Use of the Mikro-Tip ® P-V catheter should be restricted to specialists who are familiar with, and have been trained to perform, the catheterization procedures for which the device is intended  The Mikro-Tip ® P-V catheter should be inspected for damage (cracking, kinks, etc.) prior to each use.

  • Page 33: Hardware

     When using the open chest approach to insert the Mikro-Tip ® P-V catheter into the left ventricle, do not push the catheter tip directly through the left ventricular wall. First, make an entry hole in the ventricular apex with a needle, and then insert the catheter through the hole.

  • Page 34: Cables

    Use the fuse type indicated on the rear panel. Other than the fuses, the MPVS Ultra has no user-serviceable parts. Do not open the enclosure or any cable connectors. Contact Millar or your distributor for service.

  • Page 35: Technical Specifications

    Technical Specifications Pressure Transducer Characteristics Specification Value Transducer Sensitivity 5 µV/V/mmHg, nominal Bridge Excitation Load 1000 ohms, nominal Resistance 350 ohms, minimum Transducer Bridge Excitation 5.0 V , nominal Signal Input Resistance 50 mega-ohms, nominal Input connector for system Five-pin Redel or ODU Pressure Outputs Specification Value...
  • Page 36 Volume/Conductance Outputs Specification Value Sensitivity Seven gain settings with the following maximal conductance inputs for single field (SF) and dual field (DF) configuration at 20 or 100 uA excitation: Gain SF-100 SF-20 DF-100 Units 3.33 mS/segment 6.67 mS/segment 16.7 mS/segment 33.4 mS/segment 66.6...
  • Page 37 Specification Value Gain 2000 X Frequency Response Band pass filter from 0.5Hz to 35Hz (-3dB attenuation) Software enabled/disabled 60Hz notch filter Source Software selectable between external leads connected through front panel receptacle and primary conductance excitation electrodes (for IECG). Power Specification Value Input (Universal)

  • Page 38: Technical Support

    Technical Support Technical Support The Purchaser is entitled to free technical support for any Millar product. Millar’s technical support staff can provide help and advice concerning installation, operation, particular uses and problems with Millar products. Millar’s technical support staff will not provide experimental protocols or procedural instructions for conducting experiments.

  • Page 39: Recommended Accessories

    Requirements The system has been qualified with power cords whose maximum length is 2.5m (8′ 2″). The input connector on the MPVS Ultra rear panel is a standard EN60320/C14, so a power cord with a standard EN60320/C13 connector is required.
  • Page 40 BNC Cables Standard BNC cables are required for connecting to the outputs of the MPVS Ultra. BNC cable quality is important for ensuring clean signals, so be sure to use coax cables with a braided copper shield. Millar offers high-quality BNC cables in three lengths.
  • Page 41 Connector, part number PAGM07GLAC65GZ Strain relief, part number GMA.1B.054.DG Rho Cuvette 910-1060 Rho Cuvette M.I. P/N 004-2163 Rev. C...

  • Page 42: Warranty

    Millar software, hardware, and documentation are protected by copyright, and may not be reproduced or copied in any way, nor may products be derived from or based on it. Millar retains the exclusive ownership of the trademarks represented by its company name, logo, and product names.
  • Page 43 Since factors beyond Millar’s control may directly affect the product and the results obtained from its use, Millar or its agents or employees shall not be liable for any incidental or consequential loss, damage, or expense arising directly or indirectly from the use of this product.
  • Page 44 Millar products. Millar’s technical support staff will not provide experimental protocols or procedural instructions for conducting experiments. However, information of this type may be provided in the supplied product documentation, or on the Millar web site.

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