Explanting rat telemeters

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Kaha Sciences rat telemeters are designed to be explanted, cleaned, sterilized and reused. Care should be taken not to cut or damage the pressure catheter or electrode leads during explantation.

Key points to consider:

  • Take care not to cut or damage the telemeter body or suture tabs (especially if your telemeter is silicone encapsulated).
  • Always feel for anything under the skin or muscle before cutting with scissors. Never use a scalpel during explantation.
  • Where possible, we recommend using isoflurane to lightly anesthetise your rat before intraperitoneal injection with pentobarb (this makes it easier to feel for the body of the telemeter before injecting into the abdomen).
  • Do not decapitate your animal if pressure, biopotential or oxygen leads are implanted in the brain or neck.
  • When removing the pressure catheter or electrodes, always feel for or visualize/expose the attachment site and carefully remove the glue/sutures. Do not pull on the catheter or lead as this may cause damage.
  • Pressure catheters/telemeters must be placed straight into water or tergazyme solution at the time of explantation. Do not allow blood or tissue to dry on the sensor (see below for a video showing cleaning of the pressure catheter).

Cleaning the pressure catheter

  1. After removing the telemeter from the animal, immediately soak it in a beaker or dish filled with fresh saline or distilled water. Keep soaking until you are ready to continue cleaning; DO NOT allow it to dry.
  2. Soak the whole telemeter in a recommended enzymatic cleaning solution (listed below). This is essential to prevent protein build-up on the pressure sensor.  Without the use of an enzymatic cleaner, a protein film will form that can result in pressure signal drift.
Type Trade Name Manufacturer Active Ingredient Soak Time/Temp
Enzymatic Detergent Enzol® (in UK: Cidezyme®) Advanced Sterilization Products (J&J) Propylene Glycol 15 mins / room temperature
Endozine® Ruhoff Corporation Propylene Glycol 15 mins / room temperature
Terg-A-Zyme® Alconox Sodium Dodecylbenzene 15 mins / room temperature
  1. After soaking (recommended times), gently wipe the sensing tip under a microscope with a soft cotton gauze pad or swab sticks to remove any remaining film or deposits. Care must be taken not to damage the sensing tip.
  2. After soaking and wiping, thoroughly rinse the telemeter with fresh distilled water or saline.
  3. After rinsing is complete, gently dry the catheter as follows:
    • Fold a soft tissue or kim wipe
    • Use gentle stroking to dry the catheter tip.
    • Do not pull the catheter tip through a folded tissue.
    • Do not allow the catheter to air dry on a tray, table, or counter top.
  4. After the cleaning and drying procedure is finished:
    • Protect the sensor area on the catheter tip by carefully placing it in the foam that came with the telemeter.
    • Return the telemeter to its original packaging.

IMPORTANT: Delays in rinsing a telemeter after removal will reduce cleaning effectiveness!  Examine the pressure sensor active surface (diaphragm) for blood or materials not removed by cleaning.  A dirty sensor may cause baseline drift when used the next time.

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