Good afternoon! Today’s educational topic: What ACTUALLY happens when you lose a limb lead during transcutaneous pacing?
We place limb leads on patients to determine rate and rhythm. Once we determine that a patient meets the criteria for pacing, we rely on those limb leads to confirm “electrical capture” of the heart, telling us the heart has responded to the electricity. We increase the milliamps to ensure there are corresponding peripheral pulses – otherwise known as “mechanical capture” which ensures us that there is also contractility of the heart present with every electrical impulse. This is ultimately how we know TCP has been effective in restoring perfusion.
All of our lifepak monitors are set up with default settings of TCP as a DEMAND pacer. A DEMAND pacer takes any underlying rhythm into consideration as you set the rate. For instance, if you set the TCP to a standard rate of 80 – the pacer will not “fire” during an underlying intrinsic rate, but rather supplement it to a total rate of 80.
So…what happens when we “lose” or disconnect a limb lead during TCP? Do we also “lose” the pacer?
No.
Our monitors are also set up in a way that allows the pacer to continue despite limb lead removal – the default settings recognize a loss of rhythm recognition and the monitor automatically switches to “non-demand” pacing. Non-demand pacing does not take any underlying rhythm into consideration and paces strictly at the rate at which you have set. It will pace “over” any intrinsic rate.
If you notice on the strips I have attached, the first strip you will see the limb leads are on – you can see pacer spikes in the ECG and the arrows indicating a TCP delivery at the bottom of the strip, with pauses for intrinsic beats. You will also note an upside down triangle in the rhythm itself denoting each intrinsic beat. At the top right, you will see “sensing lead II Demand pacing”.
The second strip, you will notice a lead has been pulled off the patient. In the corner, you see the monitor has automatically switched to non-demand pacing, and there is no pause in the pacer arrows at the bottom. The only thing you are not able to see or verify is underlying rhythm and electrical capture. However, the monitor is still actively pacing the patient.
The moral of today’s education: if you lose a limb lead during TCP – do not panic, and do not automatically stop or pause the pacer! It is still functional. Reach over and check for mechanical capture via pulse check while you reattach your leads. (Or switch your lead to paddles on your monitor if you think about it.) Either way – the misconception that you NEED your limb leads on to pace – is a common EMS fallacy.
Once you replace your limb leads, your monitor will again automatically sense a rhythm and switch back to “demand” pacing at the same rate and milliamps you already have set.
As always, if you have any questions, let me know!
Melanie Higgins, BS, NRP Captain – EMS Quality Assurance Division of Emergency Services 16232 Elliott Parkway Williamsport, MD 21795 (cell) 301-491-2454 (office) 240-313-4376 (fax) 240-313-4375
We place limb leads on patients to determine rate and rhythm. Once we determine that a patient meets the criteria for pacing, we rely on those limb leads to confirm “electrical capture” of the heart, telling us the heart has responded to the electricity. We increase the milliamps to ensure there are corresponding peripheral pulses – otherwise known as “mechanical capture” which ensures us that there is also contractility of the heart present with every electrical impulse. This is ultimately how we know TCP has been effective in restoring perfusion.
All of our lifepak monitors are set up with default settings of TCP as a DEMAND pacer. A DEMAND pacer takes any underlying rhythm into consideration as you set the rate. For instance, if you set the TCP to a standard rate of 80 – the pacer will not “fire” during an underlying intrinsic rate, but rather supplement it to a total rate of 80.
So…what happens when we “lose” or disconnect a limb lead during TCP? Do we also “lose” the pacer?
No.
Our monitors are also set up in a way that allows the pacer to continue despite limb lead removal – the default settings recognize a loss of rhythm recognition and the monitor automatically switches to “non-demand” pacing. Non-demand pacing does not take any underlying rhythm into consideration and paces strictly at the rate at which you have set. It will pace “over” any intrinsic rate.
If you notice on the strips I have attached, the first strip you will see the limb leads are on – you can see pacer spikes in the ECG and the arrows indicating a TCP delivery at the bottom of the strip, with pauses for intrinsic beats. You will also note an upside down triangle in the rhythm itself denoting each intrinsic beat. At the top right, you will see “sensing lead II Demand pacing”.
The second strip, you will notice a lead has been pulled off the patient. In the corner, you see the monitor has automatically switched to non-demand pacing, and there is no pause in the pacer arrows at the bottom. The only thing you are not able to see or verify is underlying rhythm and electrical capture. However, the monitor is still actively pacing the patient.
The moral of today’s education: if you lose a limb lead during TCP – do not panic, and do not automatically stop or pause the pacer! It is still functional. Reach over and check for mechanical capture via pulse check while you reattach your leads. (Or switch your lead to paddles on your monitor if you think about it.) Either way – the misconception that you NEED your limb leads on to pace – is a common EMS fallacy.
Once you replace your limb leads, your monitor will again automatically sense a rhythm and switch back to “demand” pacing at the same rate and milliamps you already have set.
As always, if you have any questions, let me know!
Melanie Higgins, BS, NRP Captain – EMS Quality Assurance Division of Emergency Services 16232 Elliott Parkway Williamsport, MD 21795 (cell) 301-491-2454 (office) 240-313-4376 (fax) 240-313-4375
ECG-TCP-loss-of-limb-lead.pdf