A common thing that can happen with any ECG is a patient connectivity problem. This is usually either between the metal banana plug on one or more of the patient electrode patches or the patch/clip itself, particularly on the limb electrodes (LL, LA, RL and RA).
Note that these issues can happen even to the most experienced ECG operators and is rarely due to the way the electrodes have been affixed to the patient; most often there is something going on with the patch or the parts connecting it to the patient.
Note: The most important thing to remember is that all four limb electrodes (LL, LA, RL and RA) must be making contact with the patient properly to get a tracing from this ECG device. If ANY of the limb electrodes aren’t making contact (either between the clips and the banana plug) or through the patient patches, there will be no tracing or the tracing will be unstable or have a lot of “noise”. Be sure to focus any troubleshooting efforts on these four limb leads first.
¶ Run a quick test of the ECG leads
The following process can be done with most ECG devices in the market to help quickly identify where the connection issue is happening.
1. Unplug the clips from the end of the banana plugs for the following leads: LL, LA, RL and RA (the limb leads).
2. Start an ECG capture (without a patient present, just the ECG device connected to the computer).
3. Touch the four limb lead connectors together, metal on metal. This requires all of the four leads (mentioned in step 1) to be touching each other at the same time by the metal part of the banana plugs.
4. Look at the screen; the ECG tracing should show what appears to be a flat line. If the banana plugs are held together nicely, then it should be a clean flat line or close to it. Some ECGs (such as the Amedtec Cardiopart ECG or Norav PC-ECG) may have a large amount of noise present in the trace even when holding the pins together, though all of the limb leads should show a reading that is still useful in identifying if there is a physical fault. If you are having problems with one of the V1 to V6 leads, introduce any of those leads to the four limb leads and it should flatline too.
If this works nicely, then the problem is likely with the contact with the clips/patches and/or the patient. Try turning the banana plug a little bit when the clip is on the end to ensure that the metal parts are making good contact. Also, try cleaning the metal banana plugs with an alcohol-based solution and try testing again. Also, see Ambu Bluesensor M electrode issue with ECG banana plugs for the solution to issues that may arise from the use of those electrodes.
Faulty and/or expired patches can sometimes cause this issue, as the gel on most modern patches can deteriorate over time, particularly if left in a hot/sunny area. Please check the ECG electrode's expiry dates just in case they have expired! Many customers choose to store their patches in a sealed bag/container in the fridge to prolong their life. If none of the above works, try to use a few new patches.
Faulty clips can also cause this. We have found that some brands of ECG clips are more prone to internal cracked plastic and conductors causing intermittent contact issues. If you do find any physical damage has occurred to the clips, try another clip/patch combination that suits the ECG (talk to your usual clip/patch distributor(s) about the best combination to use). You can also swap the clips (not the patches or lead positions) from the V1-V6 leads to the limb leads for working out where the problem resides. An example of clips with cracks in the hard plastic can be found below; in this case, the internal conductor had been broken leading to the outer hardened clear plastic to also be cracked.
If the above process does not result in similar results to above or you still have problems, it could point towards a physical problem with the device or its electrode leads, though this would need to be confirmed. Please contact LEMR Support if further assistance is required.
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LEMR customers can get help by contacting LEMR Support.