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Millar and ADInstruments

Best Practice Tips: Millar Pressure and Pressure Volume Catheters

Millar Mikro-Tip® catheters are the world’s most accurate physiological pressure catheters, providing sensitive measurement of pressure parameters, specialized for investigating airway pressure, spinal pressure or one of the many cardiovascular pressures.

Millar catheters are superior because they:

  • Are extremely sensitive to small pressure changes.
  • Have no motion artifact.
  • Have no catheter whip artifact.
  • Have excellent frequency response (flat to 10kHz).
  • Have no signal attenuation.

Due to their extreme sensitivity, these catheters are also sensitive to other factors including:

  • Light
  • Moisture
  • Temperature
  • Electro-Static Discharge
  • Excessive pressure, force or aggravation

This means that they require a certain level of care to ensure accuracy and the anticipated lifespan of your catheters. This page is intended to provide you with a few best practice tips to help get you started with your catheters.

Millar Inc. is a pioneer in the development of advanced pressure sensor technology to fuel groundbreaking research. Providing tools for unprecedented accuracy and precision in small to large animal cardiovascular research including hemodynamics and cardiovascular electrophysiology, Millar’s Mikro -Tip® catheter technology supports acquisition of the following signals:

  • Pressure: Accurately measure arterial, vascular or interstitial fluid pressure (IFP) pressure signals direct at the source;
  • Pressure-Volume: Measure high-fidelity ventricular pressure and volume signals for direct, real-time complete cardiac function;
  • Intracardiac ECG: Apply pacing and recording protocols to determine electrical properties of the atrium and ventricle

Best Practice Tips

NOTE: For more comprehensive details relevant to your chosen Millar Mikro-Tip® Catheter model please refer to the Instructions For Use guides provided below.

Intended Use - These products are designed for use by professionals with appropriate education and training in life science and medical research applications including catheterization procedures on animals, for which the device is intended.

Storage

  • Store your catheter in a dark, cool, and dry place.
  • Keep the catheter stored in the plastic tray provided.
  • Your catheter will be shipped with a foam or plastic cover placed over the catheter tip for protection. These should be in place during handling and when not in use, the tip should be left in this protective cover within the tray.

 

Maximizing the Life of Millar Research Tools

 

Excerpt taken from February 2017 Webinar produced by Millar.

Status message

TOP TIP: To prevent baseline drift always pre-soak the pressure sensor in sterile water or isotonic saline at 37℃ for 30 minutes prior to every calibration and use.

Handling and Care

  DO DO NOT
Catheters (and/or pigtails), Pressure Sensors & Electrodes
  • Inspect for damage (cracking, kinks etc) prior to each use.
  • Grip 5-10mm away from the sensor/electrode area to avoid damage to the fragile wires inside.
  • If forceps or other surgical tools must be used to grip and introduce the catheter, slip soft surgical tubing over tips of the tool to cushion interface with catheter.
  • Disconnect during electrical defibrillation or electrosurgery.
  • Use an electrostatic discharge mat or grounding bracelet when handling the catheter (recommended).
  • Use a sheath introducer (o-ring type sealing introducer) to insert catheter in large animal models.
  • Clean immediately after use.
  • Bend, kink, cut, crease, knot, fold, crush etc. Especially around the sensor, electrode area.
  • Tap the sensor or electrodes against a rigid surface.
  • Grip the catheter anywhere near the sensor/electrode area incl. between the electrodes or between the electrodes and the pressure sensor case.
  • Use sharp objects in the sensor/electrode area.
  • Apply excessive force or pressure to the sensor or electrodes e.g do not set objects on top of catheter or tighten sutures over sensors/electrode area.
  • Touch the sensor element while the catheter is disconnected from monitoring equipment as the pressure sensor element is sensitive to electrostatic charge.
  • Use cusp-type self-sealing introducers*.
  • Clean with stiff-bristled brush.
  • Clean with high pressure water jet.
Surgical Application techniques(recommended duration of each diagnostic procedure should be under 4 hours)
  • Pull back slightly if resistance is encountered while inserting catheter and then try advancing again.
  • Advance the sensor/electrode area completely beyond the proximal suture before tightening suture.
  • Loosen the proximal suture before pulling catheter out to avoid sensor or electrodes catching.
  • Apply excessive force when inserting or removing the catheter as the catheter may incur damage and you could traumatize the linings and associated tissue of the cardiovascular system.
  • Damage the catheter with the tips of any forceps or tweezers that are used to grip the artery when inserting the catheter.
  • Push the catheter tip directly through the left ventricular wall, instead make an entry hole in ventricular apex with a needle first, then insert the catheter through the hole (open chest, direct LV approach).
Connector and Cables
  • Protect connectors from fluid.
  • Immerse connectors in liquid.
Cleaning
  • Keep catheters and sensors (and lumen in applicable models) wet until cleaning.
  • Clean thoroughly with approved enzymatic cleanser (Terg-A-Zyme or equivalent) immediately after use.
  • Expose to alcohol, cresols, phenols, mercury compounds, hypochlorites, acetone, peroxide, silicone chlorine, xylenes, trichloroethylene, or freon.
  • Use ultrasonic cleaner.
  • Immerse electrical connector.
Disinfection or Sterilization
  • Dry catheter (and lumen for volume and pv special) before sterilizing.
  • Remove protective cover from catheter.
  • Place in plastic shipping tray with protective cover once sterilized.
  • Autoclave, irradiate (gamma/e-beam), plasma, peroxide or formaldehyde vapor solutions.
  • Use SporoxTM or Cidex® PA Solutions.
  • Allow any body fluids to collect under protective covering on catheter connector, otherwise sterilization cannot be assured.

* Such introducers may be used in conjunction with a thin-walled introducer sleeve over the sensor to protect the sensor during insertion and withdrawal for large animal applications.

DOWNLOAD PDF OF BEST PRACTICE TIPS

Troubleshooting and Support

 

Summary

Problem Probable Cause Corrective Action
Excessive Pressure signal drift.
  1. Deposit of foreign material on the diaphragm of the pressure signal.
  2. Failure to soak catheter in sterile water or saline solution at 37℃ for 30min before use.
  1. Follow cleaning instructions.
  2. Clean and sterilize catheter and then ensure to pre-soak as per instructions directly before trying procedure again.
If problem persists, contact your support representative.
Pressure sensor will not balance (zero).

Moisture in the connectors, damage to wires in the catheter, or fractured strain gauge within pressure sensor.

Follow Operating Instructions or substitute a transducer known to be operating properly into the recording system. If problem persists, contact your support representative.

Noisy or erratic volume signal.

Damage to electrodes or electrode-wire bond (“open electrode”).

Follow Operating Instructions or substitute a transducer known to be operating in the recording system. If problem persists, contact your support representative.

Training and Support

ADInstruments global training and support systems mean that there is always help at hand to support you with your endeavors and help you learn ‘best practices’ to move your research forward faster.

Additional Information

Find out more about our exclusive partnership with Millar

For access to more information and videos regarding catheter use and care, surgical procedures, and publications referencing Millar Mikro-Tip catheters, please register for a free account on Millar’s Knowledge Center.

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Warranties

All Millar Mikro-Tip® Catheters offer a warranty to protect from defects in materials and workmanship and Millar will at no charge either repair or replace as appropriate. THIS DOES NOT COVER DAMAGE DUE TO ALTERATIONS, MISUSE, ABUSE, NEGLIGENCE OR ACCIDENT. Warranty dates are calculated from date of original shipment to original purchaser:

  • Mikro-Tip® Ultra-Miniature Pressure-Volume Catheters: 6 months.
  • Mikro-Tip® Ultra-Special Pressure-Volume Combination Catheter Transducers: 60 days or five uses (whichever occurs first).
  • Mikro-Tip® Catheter Pressure Transducers: 365 day (1 year).
    • SPR-524 is warranted for a period of 30 days.
    • SPR-524 is non-repairable.