Difference between pulse and HR

InArduisFidelis · Jun 4, 2016

I am assuming HR in this case means that number of QRS complexes detected on the ECG. When it comes to pulse are you seeing a difference in an auscultated pulse, palpated pulse, or what is picked up on a pulse oximeter?

romantic · Jun 4, 2016

Yes. HR is ventricular response; while pulse was picked by pulse oximetry. And every time the pulse was in 140s, the Sats remained OK, in 93-95%.

Thank you for asking to clarify.

InArduisFidelis · Jun 4, 2016

Pulse oximetry can be notoriously inaccurate, especially with Afib. I would trust the ECG rate over pulse oximetry. That said being said, a couple pointers with discrepancies:

1) Make sure that the monitor lead that your HR is being monitored off of has a good tracing. If you have a low voltage QRS, tall T-waves, or the baseline is all over the place you can't really trust the HR number that the monitor displays. When these things persist you should either attempt new stickers/lead placement or switch your lead on the monitor. Your arrhythmia alarms are most likely going to be based off of that as well so crummy tracing=erroneous alarms. Don't be afraid to look at a strip and count out the QRS complexes to double check, because the software is only so smart on the monitoring systems.

2) I've heard a good rule of thumb that if your pulse wave count on the pulse oximetry and your ECG HR are off by more than 10bpm that you shouldn't really trust that sat reading, so be cautious when you see big discrepancies and consider troubleshooting the sat probe (placement, warming the extremity, alternate site)

RescueNinjaKy · Jun 4, 2016

If your patient has arrhythmia, do not go by pulse ox to get the hr, especially atrial fibrillation. The pulse ox will at times count the p waves as a beat and give you an inaccurate number. Always go by your tele box over that pulse ox. This is a very common mistake that I've seen with newer nurses or nurses who aren't familiar with arrhythmia/telemetry.

MunoRN, RN · Jun 4, 2016

Heart rate and pulse are two different measurements, so it's possible for them to be different without one of them being inaccurate. Heart rate is the number of presumed ventricular contractions usually by EKG, Pulse is the how many of those contractions result in detectable pulsatile flow which can vary depending how and where the pulse is being assessed. A person may have a heart rate of 90, a radial pulse of 80, a palpable pedal pulse of 60 and a doppler pedal pulse of 70, for instance.

romantic · Jun 4, 2016

Thank you.

However My question was why pulse is higher than HR? patient has afib. On telemetry. Lower pulse than HR makes sense.

In my case on telemetry Pulse was higher than HR episodically. HR 80-100b/min; however, pulse went up to 140b/min. patient was asymptomatic; Sats were 93-95% on RA. The patient was on continuous pulse oximetry. That is how I noticed the difference.

romantic · Jun 4, 2016

Thank you for your reply.

I don't think that pulse oximetry can count p waves or can react to atrial contractions.

However, Your post made me curious to find out how pulse oximetry works. I am reading the manual.

Hopefully I will get the answer to my question.

NotAllWhoWandeRN, ASN, RN · Jun 6, 2016

Thank you.
However My question was why pulse is higher than HR? patient has afib. On telemetry. Lower pulse than HR makes sense.
In my case on telemetry Pulse was higher than HR episodically. HR 80-100b/min; however, pulse went up to 140b/min. patient was asymptomatic; Sats were 93-95% on RA. The patient was on continuous pulse oximetry. That is how I noticed the difference.

They did answer your question: the pulse reading was inaccurate. Heart rate is the number of cardiac contractions. Pulse rate is the number of detectable waves of coursing blood that get pumped through wherever you are checking. When you are feeling a pulse you are palpating for that expansion in a large vessel as blood is pumped through. As has been mentioned, with impaired cardiac function you can have pulse deficits, leading to a pulse rate lower than the heart rate. The pulse ox measures blood volume variation in smaller vessels in your finger/toe/earlobe/whatnot. It is not foolproof.

AspiringNurseMW · Jun 6, 2016

I can't answer the question but did you take a manual pulse to see if the pulse ox was accurate?

Lev, MSN, RN, NP · Jun 6, 2016

The pulse can never be higher than the heart rate. The peripheral pulse rate can be lower than the HR. I will make sure to chart both if there is a discrepency. Sometimes when a patient is in a Bigeminy pattern or having frequent PVCs, the PVCs won't perfuse and cause a peripheral pulse for those beat. Kind of the same with pulseless vtach or vtach with a pulse. I've had patients in Bigeminy with a HR of 80 and a peripheral pulse of 40.

The patient probably had a fine tremor which created an artificial waveform.

akulahawkRN, ADN, RN, EMT-P · Jun 6, 2016

As others have said, the pulse rate and heart rate can be different but the actual pulse rate (in normal physiology) can never be higher than the heart rate. The ecg and SpO2 units probably have different "rolling windows" for determining their rate values. The "rolling window" for an ECG unit may be just 6 seconds while an SpO2 window may be 10 seconds, and if a heart rate changes acutely within the window, you may see that change first happen in the ECG and if there's a little variation, say 1-4 beats per minute, you might not have the two devices show exactly coupled rates. Both types of units are going to look for certain waveforms, in particular, that's a spike that is definitely above or below some point. (With ECG units, it's possible for the unit to count really peaked T-waves in addition to QRS complexes, doubling the rate.) With SpO2 units, if the patient's fingers are moving around at just the right time and generally repeatable amplitude, the unit will pick that up and interpret that as a pulse when all it's actually doing is picking up patient movement artifact. Trust me when I say that I can (quite literally) grab a couple of ECG leads and very easily simulate V-Tach or (much easier) V-Fib, with all of it being induced artifact. Modern ECG machines have such sensitive electronics that they'll pick up induced voltage from simple movement of the leads.