Uses of Pulse Oximeter in Rhythm Monitoring

[Jerry_NJ]

Most (all?) of you have seen the small clip-on-the-finger over a finger nail used in doctor offices to measure the Oxygen Saturation level in your blood (target 95% or better I believe).  These doctors don't have a pulse display on their units or simply prefer the manual method to measure pulse rate, which both the nurse and doctor do, the doctor of course also listens to my heart with a stethoscope.

It is difficult for me to feel my pulse (a blessing in many respects) and I have for years used a stethoscope to count my pulses, heart rate.  The only indication I have of the blood oxygen saturation is if I am dizzy or breathless more than what I recall as normal.  I have thought that it would be helpful to be able to measure the O2 level at those times and even to run a DIY sleep test (this in general would require a recording meter).

When I saw this type instrument with a combined HR and O2 plus a pulse intensity readout for under $25 delivered I ordered one.

Here's what I learned for my profile and what I have concluded about a number of aspects of my AFib condition on my physical being.  I compared/checked the device HR by counting my HR while using the clip on, good agreement.  I checked my wife who does not have any diagnosed heart conditions and found reaso6 nable readings and a smoother more uniform heart intensity readout than I got for myself with AFib.. as expected.  I take the intensity differences between her and me indicative, not quantitative even though it is provided via a 6 bar readout scale.  

I found my O2 consistently obove 95% even when I was feeling O2 starved, like when standing up quickly.  I also found my HR reasonable and in the 70s when resting and typically around 100 when in light physical activity.  

Now for sleeping, or really maximum rested times.  

I did not get a recording meter for $25, but as I wake up often during the night it is easy for me to clip the device on with minimum physical effort when I wake up.  Some interesting findings (to me) - I am on a normal release Metoprolol (BB) and Calcium CB which is taken at about 10:30 PM, so by 1:30 AM I am still in the fully medicated area of the BB concentration (half life of 4 hours assumed).  

Early in the morning (around 2 AM) I found my fully relaxed in bed HR as low as upper 50s and O2 levels as low as 90%.  Later in the morning (around 5 or 6 AM) I found my HR around 70, suggesting the BB had lost a considerable % of its strength (now in its 2nd half live, about 75% metabolized) and the O2 levels over 95%.  This seems reasonable and in fact during the day my seated and fully resting HR runs in the 70s to 80s.    The lower O2 level of 90%, which is the threshold of trouble as I understand, at 2 AM is a minor concern to me.  This many not be a trouble indicator under the condition of being under BB and CCB near full strength and just in/out of sleep resting state.  I continue to check and see if my results are consistent/repeated.

In any case I find having this testing device affordable and quick way to check my HR, and also get the O2 saturation  -  the value of the heart intensity readout is not clear, but does give me some concern... guess it is the variations I hear with the stethoscope.

[ireneo]

Sounds interesting. I don't worry much about my O2 except when my asthma flares up. Then I use my peak flow meter to see how my lungs are working. I have a strong pulse so I can check rate any time: either wrist or carotid.

I'm being stupid here but what is "heart intensity?"

[Jerry_NJ]

The device I have has a 7bar element stacked vertically (so to speak) and this stack of bars is triggered by each ventricle beat.  In my case the the number of bars seldom exceeds 4 bars.  Using the device to check my wife numbers more pulses went the full 7 bars... best I can recall at the moment.  I simply check on her finger to see what a healthy heart would register.  The "intensity" display was very regular and strong.  No so in my case.  On the other hand my O2 was as good or better and her resting HR was in the 80s, higher than mine, mine being held down with beta and calcium channel blockers.

My cardiologist has agreed with my request to change my Metoprolol to Atenolol which I learned in another thread has a longer half life (slower release for regular non-SR tablets) and had a lower penetration.  I have read other "good things" about Atenolol.  I'll see if I have more steady HR (it is very easy to check now and I will confirm while still on Metoprolol that my sleepy rest rate changes significantly between 2 AM and 6 AM, given my sleeping problems Im sure I'll be awake.  As noted, last night I saw a HR much lower at 2 AM about 3 hours into the BB dose run down, to the HR at 6 AM 7 hours into the BB dose run down.  Then too, if the change in BB lets me sleep more restfully I may not be waking up at these wee hours times.

[itdood]

I have one of those as-well!  very cool to get a better understanding.  Your resting pulse is excellent for having afib.  So is you O2 sat.  the variance you are seeing at night could also be due to your own natural circadian rhythm.  I'm not medicated at all, and I find that my average HR varies throughout the night.  IN the wee hours, respiration slows down greatly which to me would have the greatest affect on o2 sat.

anything > 90 is fine.

[itdood]

p.s., O2 sat is a lot more affected by respiration then HR, in my humble opinion.  For instance, when I was on top of pikes peak my heart rate didn't change and I didn't feel short of breath, but I was dizzy at times and that's from low 02 sat.

[Jerry_NJ]

I have in recent years chronic nasal congestion, but almost only when lying down, as in bed time.  While I can breath through my mount, and dry mouth in the night says I'm doing that more than I'd like, it is better to breath through the nose.  

The congestion sometimes causes me to feel like I am suffocating...mental? many be.  This is another condition driving my interest in the O2 sat level.  

I took my 25 mg BB about an hour ago, so I assume my BB level is near maximum and my resting HR (sitting in front of my computer and TV) is about 80.  It will be interesting to see if it drops again into the upper 50s in the early hours, just after waking up form a couple of hours of sleep.

I'll be on Metoprolol for my BB for another 10 days or so.  I plan to use up the pills I have before changing to the new brand I requested.  My cardiologist is likely just humoring me by agreeing to my request to try a different BB.  He had been reluctant in the past saying why change anything you are doing well.. and I say I'd like to do better.  I have read not all BB are equal, they are somehow different, including the half life on concentration in the blood, and in how "selective" they are in not affecting the brain operations.

[ireneo]

Thanks for the explanation on "intensity." So more bars is higher intensity which is a good thing. Palpitations which feel like a pounding heart seem like a bad thing. I wonder if they register on the meter.

Then lower bars mean the heart isn't beating as effectively as it should.

Interesting.

[Jerry_NJ]

I'm not sure the "intensity" is a measure of efficiency.  My echo measured EF is over 60% which is considered good, yet the intensity readout goes most of the time to only 4 bars.  

The device itself appears to get its data by shinning a very bright LED through the finger to a receiver on the opposite side of the finger.  I have no idea how that can determine the % saturation but it seems possible to me that the light signal is modulated by the pulsating pressure/blood in the finger.  The height (number of bars) may be more affected by the blood pressure and the difference between the upper/lower values. If that is the case the high bar reading would suggest high BP, maybe too hight.  I looked briefly at the instructions that came with the device to learn more about the intensity reading, and understanding what it tells.  The instructions were silent - I'll see if I can find some explanation on the web.

[helyanna]

I have used a pulse oximeter for many years. I use it when I have some blood circulatory problems. I think that the intensity may be affected by many things. When I go out and there is a cold weather, the blood circulation  to my fingers decreases. Then the intensity may be low. It can sometimes be low (two bars) even in the room temperature, and on the other hand, sometimes can show all the bars (I cannot count them). One reason for low bars could be the position of the arm (the artery can be compressed). But often I cannot find any cause. The variation can result form the normal autonomous regulation.

[Jerry_NJ]

Thanks for sharing your experience, I find it helpful as I am sure others who have or are considering such a device find your reply helpful.

The "Intensity" may have come out of my "head"... a Jerry-creation.  I can not find that term used in my brief search of the "literature".  Clearly, it is more than a pulse indicator, a simple single bar flashing would accomplish that.

I have struggled to determine the number of bars in the pulse "indicator" (I'll now call it).  I rarely hit the top and when I do it is a very brief flash, but I am sure it is at least six, and I see much of my indication being up;down between bar 2 and bar 4.  I have AFib, and am in AFib all the time.

I did look a little deeper into the technical details and learned that the device uses to (high intensity - my term again) LED light sources (top over finger nail) one is visible Red the other invisible Infra-Red.  With these light sources passing through the finger and picked up by detectors on the bottom of the device. a read-out of the color of the arterial blood is determined. then with the wonders of a micro processor with data base and firmware it can computer the O2 saturation, which is indicated by the color of the hemoglobin carrying oxygen, or not carrying.  I believe through this detection the device also "sees" the pulsing and thus can display the HR.  As for intensity, not sure that is a good term for the bar readout.

[ireneo]

This is confusing, isn't it?  So the oxygen level is shown by a digital readout (97 for example) and pulse rate is shown by number as well. The big mystery is the purpose of the bars. Funny the instructions don't clearly explain what that's for.

I like the other response about how things can change due to circulation: being cold, hot, position of arm. Another question: is there a difference between a skinny finger and a chubby finger? LOL Seriously. Can the LED and infra red read as easily on a chubby finger? Will a hand swollen by fluid retention make a difference in readings?

Ah well. Sweet mysteries of life.

[Jerry_NJ]

The reading I've done says "yes" to your question... the bone and finger do make a difference, and "stuff" like nail polish may prevent the device from working.  

I did the one calibration check I could make, the HR, I counted my pulse and over a period of time, 15 seconds minimum, and the count method gave a HR within a count or two f what the monitor displayed.  Here I assume the device "sees" the movement in the vein (artery - whatever its called) and counts each expansion as a pulse.  Just a guess, but continuing it seems to me an older person, for example, would on average have harder/stiffer veins/arteries and thus less expansion, which is reflected by the number of bars displayed - if this is true it the number of bars has nothing to due with the blood flow beyond the variations it displays on an individual - and that variation may be due to movement of the hand/finger or other external causes. I have decided to accept the HR and O2 are good-enough and the number of bars a curiosity of the device. .

[helyanna]

Although I am using atenolol (Tenoblock 75 + 25 mg per day), I can hit the other margin of the screen during some time of the day. I have got accustomed to atenolol, because of using it since the eighties.

Nail varnish or othervise coloured or very thick nails may cause error.

Because it was thought that I could have exceptional hemoglobin (which I don't have), I read about hemoglobins in the internet. Some hemoglobin variants can bind oxygen very firmly and do not give it easily to tissues. Such hemoglobins may give false information about the state of oxygenation of the tissues, although the Hb's O2 saturation is good. But the percent of an exceptional variant may be low among the normal variant, so it may not cause a bad error (I don't know). Some people can also have higher amounts of methemoglobin. Its colour is different from the normal hemoglobin, and therefore it might cause error.

[Jerry_NJ]

I am working on health issue that may or may not be related but one of the main reasons I purchased the Oximeter was to see if I could get any hard data suggesting I press for a sleep study - apnea.  This comes more from my nasal congestion battle than from my AFig condition.  I do wake up at night with some congestion panic, and wonder is my blood oxygen low.

Last night I had a bout of the waking in the early hours of the morning and feeling short of breath, or even suffocation.  I immediately took a deep breath through my mouth and realized I had some "dry mouth" feeling so I know I was breathing through my mouth while asleep.  I also checked and determined my left nostril was clear, only the right one was plugged.  Checking the Oximeter I found my pulst in the low 70s (good) and the O2 was in the low 90s, even saw one 89%... then it started to increase into the 95% or higher range.  

My data is subject to device and application error and my memory, I didn't write anything down.

Does a O2 of 89%, even if rare, when just sleeping, just woke up, something to be concerned about, perhaps the O2 saturation can be lower when in a deep rest state - the HR goes to its lowest point at that time.  

[helyanna]

You may have sleep apnea. My pulmonologist has said that sleep apnea may predispose atrial fibrillation. In 2010 I had sleep polygraphy - fortunately I did not have sleep apnea.

I think that over 90% is considered normal, or sometimes over 95. I spent only 5 minutes between 90 and 95%, and no minutes under 90. Mean SpO2 was 96.7, median 97.

Sometimes, when I am falling asleep I wake up and take a deep breath. I think that my heart rate falls to fairly low and therefore I feel shortage of breath. Or it may be caused by some panic.

Has anybody noticed that you have sleep apnea? My husband probably had it 20 years ago, He has rarely also nowadays some short periods of apnea. But he does not fulfill the criteria for real disease. He is using a tennis ball in a pocket on the backside of his pyjamas shirt to hinder sleeping on his back. It is working well.

Have you noticed that sometimes, when you put the oximeter on your finger, it first gives a lower reading? It may result from the device. The error time is, however, very short. Your nighttime readings may be true.

You are doing very interesting experiments with your device. I love my pulse oxymeter - I call it as my tamagochi. A sleep polygraphy, if you could get such a holtering, would be monitoring your heart rate and oxygen saturation all the night.

[Jerry_NJ]

A 24 hour recording device is available for about $100.  Given my interesting and credible results with my real-time-only device I may invest.

The state of microelectronics, including inexpensive electronic memory, makes it very possible to make sophisticated electronics at low cost --- just look at your home computer.  What we buy today, I am talking function/capacity not miniaturization, for $500 could not be purchased for less than $50,000 twenty years ago (1993).  

Yes, the meter often comes up with an unlikely low reading for a cycle or two (not sure how long a cycle is, perhaps 5-10 seconds).  I have seen 2 AM readings of a HR in the 60s, very low for me that move into the 70s when watched for several cycles.  

I don't recall clearly when I got the 89% O2 reading but it wasn't at the end of my watch period.  I watched for a minute or two and the O2 came up closer to 95% average.

I always sleep on my side, and when I wake I can say what side I had been sleeping on as the other side of my sinus will be stopped... roll over and the stop shifts sides.  So whatever is causing the swelling is liquid based and moves to the low energy side prescribed by gravity.  It is this sinus stoppage that gives me the suffocating feeling, not a stop of breathing altogether.  My wife has trouble sleeping and she said she has never noticed me not breathing when she is awake.  Then too, I sometimes wake her with snoring, another sign of Apnea, but I go months without snoring or at least without her hearing it.

I'll talk with my GP later this month.  

[Jerry_NJ]

My ongoing learning leads me to doubt the first reading displayed, I watch for at least two or three updates (a few seconds) before taking the reading of either HR or O2%.  With this "Filter" I have not seen any O2% below the low 90s and usually 95% or above as should be the case.

The meter has been helpful in my watch on my BB change from Metoprolol to Atenolol, the subject of one or more other posts.  It has also been nice to have in my shirt pocket when I get a dizzy spell, I can stop and make a quick check of HR and Oxygen.  In most cases I see a lower than needed (apparently) HR to handle the activity change.

[Jerry_NJ]

I discussed my use of my personal Oximeter with m Primary Care doctor today at my annual physical exam.  I told him I measured a couple of reading in the very low 90s and evern 89% when I awake in the early morning hours.  

I asked if he could prescribe a home Oximeter recording test for a mini-Sleep Study. He said, yes.  I got a telephone call shortly after getting home from the testing service .  They will bring the equipment to my home on Wednesday, check me out, and pick up the equipment the next day.  They will forward the result to my doctor, I believe, immediately - assume by end of week.

I hope they don't fine me stopping breathing during sleep,wearing a CPAP mask to sleep in would be hard to adapt to.  But I feel I have enough symptoms that I need to be checked, the doctor agreed.  

I think Medicare/Insurance pays the major part of the cost, I will learn on that issue.  I'd guess it can not be more than a few $ hundred at he most anyway. I suppose one could ask, my normal mode of operation, never order something before knowing what it costs, but in this case, as is true for most medical matters, I have to  do it whatever it costs.  One really can't shop around.

[Jerry_NJ]

Prescribed Oximeter over night run made last night 11:30 PM to 7:30 AM this morning. The unit is a compact finger unit (just the Modem) with a flexible 6' or so cable connecting it to a small (about size of a medium human hand) recording and display unit.  It displays heart rate and oxygen % in real time.  The finger unit was secured by me with supplied "No stick" medical tape. I put tape around the cable and around the "clamp on" Modem.

While my concern expressed to my PM Doctor was sleep apnea, the test service is about COPD, which is the test that was run, I now understand.  I suppose if I stopped breathing for brief periods that too would show a  sudden drops in % oxygen.  I will ask my doctor about that.

An immediate concern to me was that I observed a O2 reading in the low 90% many times during my awake times. These did pass with the reading returning to 97% or more for most of the time.  I could not associate the lower readings with any sense of suffocation, our difficulty breathing.  As always I struggled with nasal congestion.

This experience is yet another experience I have with the wonderful USA medical system that I fear we will lose as the new governmental takeover of our healthcare rolls out. Here's this example of the VIP medical service we get in the USA, even those of us on Medicare with its lower payment schedule:

Monday my annual physical - doctor prescribes over night oximeter record
Wednesday equipment delivered into my hands
Thursday I have the unit packaged for a pick up by the testing company
The COPD service will read out my unit today and report today to my primary care doctor... all done in one "work week".

I believe my symptom and the prescription of testing for COPD is considered time critical, patient is at some risk of sudden complications, even death. This thinking (mine) may be what puts this test service on a "fast track", still, from what I read on this Community and in the general news this type of expedited service is not provided in many or (all?) the countries in which the government manages the delivery of health services.  I believe the USA is on a path to diminished health care, a deep sadness to me for my children and all our citizens.

[helyanna]

I hope that you will get help and be well.

I have had a couple of times nasal congestion when suddenly woken. I have postnasal drip, and my eye pain is continuying.

Recently I have found oxygen readings slightly lower than during AF. When I was walking outside during AF, my ox.% went often to99 or 100. Now it often goes to 96 during walking and I don't feel well during walking.

I have the result of a spirometria test done on March 4. There I see that MEF50 is too low, 47% before and 56 after Ventoline inhalation. The result is similar to that from a few years ago, when they said to me that I have some obstruction in my smaller bronchioles. No cause is known for this. I don't smoke. Could there be some connection with the obstruction and AF? Could AF have damaged my lungs and therefore I don't feel well during walking? I have not yet had a doctor's consultation about the spirometria result. It has to be noted that I had a long-lasting respiratory infection in January-February of this year.

[Jerry_NJ]

I would be surprised if a O2 o 96% would cause any symptoms, or "feeling bad".  I just checked mine an it reads 97%, I don't recall ever seening 100% and a 99% is very rare for me.  

As for feeling bad when walking, I can no longer walk up a hill without stopping... I think it is more a question of my legs feeling very tired/stiff, not of being breathless.  I attribute all of this to my AFib and my beta blocker med.  

This being a weekend and Easter as well today, I have nothing back from my doctor on my overnight O2% recording.  I will ask for a copy of the data to look at myself and will have a few questions if he says all looks okay.

One question is about the 02% going down to 90% or lower, even if just for brief periods... or asked another  way, is it normal when one is asleep for the O2% to drop as the need for oxygen is much reduced when in t sleeping state.

My wife said this morning that she awoke an noticed I was breathing very softly, then more normally.  She said she put a hand on my side to feel for breathing as the sound was too low even for her excellent hearing.  

I man need ot go in for a "sleep study" if there are any questions from the Recording Oximeter test.

[Jerry_NJ]

The US Health Care system is still working great.  Look at the progress in under 10 days.

Monday March 25, Annual Physical Exam.  I mention to my doctor my continuing congestion problem and my sense of suffocation sometimes when I awake form sleep.  Told him I have my own Oximeter and have observed oxygen saturation levels below 90% for brief periods.

Wednesday/Thursday March 27/28 I wear a recording Oximeter with results reported to my primary care doctor Thursday or Friday.  The equipment was delivered and picked up form my home by the COPD service company.

Monday April 1, I get a telephone call form the COPD company suggestion delivery of oxygen, I said "hold on" I haven't yet discussed with my doctor.l

Tuesday April 2,  my doctor agrees supplementary oxygen is not yet confirmed as needed, refers me to a Pulmonary specialist.  Gives me a copy of the report that shows I logged over 8 minutes in the 85/86% saturation level.  I telephone the Pulmonary Specialist for an appointment, one was set for Thursday morning, April 4, and I was sent to hospital for chest X-rays which were completed within minutes of my arrival.

Bad news, is it appears I may have COPD or Apnea problems.  I may undergo a full Sleep Study, that has not yet been determined.

The value of the Oximeter I purchased has proven to be high, I would not have asked for a recording oximeter at home test if I hadn't observed the low reading when waking during my sleeping period.

[Jerry_NJ]

I had chest X-rays and when with them to a Pulmonary Specialist. He said no lung problems were indicated from the X-ray images.  But visible inspection of my throat (wind pipe) and the Oximeter record he prescribed a Sleep Study.  That will take place tomorrow night at my local hospital.

I sent a friend (fishing buddy of the past who is about 10 years younger than me) my story about the upcoming sleep study. He wrote back that he has been using a CPAP for about 4 years, and LOVES IT.  He said it showed him how good he can feel when he gets a good night's sleep.  I still hope to avoid, the Pulmonologist said some of the minor constriction in my throat could be due to being overweight, the standards says I am obese at 250 and 6'5"  I find that term obese an overstatement of my case, I weighted about 230 when I was still a runner. But, I'd rather try to lose 25 pounds than have to deal with a CPAP.   So, some good news:  Lungs look okay (in spite of my history as a past smoker) and the purchase of the Oximeter put me on the path of getting this health problem examined.  Yes, and my new doctors have all accepted me as a Medicare patient - thus my personal out-of-pocket cost will be no more than 20% of the reduced Medicare rate schedule.  I do have a secondary insurance plan but my health is so "good" I have not even paid the deductible in recent years. My secondary pays nothing until I pay the deductible as is normal.

I am not sure how much this tracks "Heart Rhythm" but as the subject says, I purchased the Oximeter to help me adjust my beta blocker (now Antenolol) that is use the heart rate reading, which I have.  I am now up to the full prescribed beta blocker dose of 25 mg every 12 hours.  I think I have adjusted to Antenolol sufficiently for that level to not "too much" dizziness when I stand.  I will report here too on the results of the Sleep Study.

[DeltaDawn23]

Jerry -- if you indeed have sleep apnea, it could be contributing to your ongoing afib.  My ep thinks my afib was caused by my (undiagnosed) sleep apnea over a number of years.  

I have used the cpap for 10 years and after a period of adjustment, it is not too bad.  I would prefer not to need it, but it is tolerable and I can't imagine trying to get along without it.  I was exhausted all the time without knowing why before I got the machine.  They do have a Nasal Aire II cannula type device that makes it possible to use with out having a mask sitting on your face, something I could not tolerate.

I just purchased a pulse oximeter and have notice when waking my oxygen is low, then slowly comes up.  I am due for a pulmonary consultation and perhaps another sleep study, so will inquire then whether this is an issue I need be concerned with.

I am in the process of switching from Norpace (been off of it for 3 days) to Rhythmol (start tomorrow).  I have been using my Atenolol and Xanax and have had just a few flutters after the first day, when I had some irregular beats.  Makes me wonder if the Atenolol alone might control it.  I see my ep in 2 weeks for an ekg and a visit to determine how I'm feeling.  I hope the Rythmol works, altho reading the precautions is the stuff of nightmares:P  I will be interested to see how it all shakes out.

Take care and keep us posted on how the sleep study goes.  Cpap is not all that bad if it comes to that and you may well feel a lot better stamina-wise.  Good luck.

[Jerry_NJ]

Hope the Rythmol works... as I think I have already told you I didn't have any side effects from Rythmol, but I didn't get any benefits either, it couldn't even hold me in NSR following an electrocardioversion.

On the sleep study:  I got home bright and early this morning from the hospital, my sleep study was done overnight.  I had some trouble sleeping, felt like I was wired for a trip to Mars if not further into space.  I think I did enough sleeping for the test to record critical data... bet I have a confirmed mild (hope mild) obstructive sleep apnea problem.  I don't know it that is related to my night time nasal congestion, but it seems possible, and for some reason I had far less over night congestion - maybe I have something in my bedroom to which I am allergic.  I don't think so, as I have had congestion when traveling and staying in hotels.   I had a breathing monitor attached to my face, looks like the supplementary oxygen feed devices, but it was to measure breathing, not provide oxygen.  I though maybe that helped keep my sinus open, the technician didn't think so, but that's a question for the doctor, not the tech.

I sent an email to a fishing buddy, who no longer lives near me, about my upcoming sleep study.  He is about 10 years younger than me and I figured I'd get some sympathy.. not so, better, he said he's been using a CPAP for about 4 years and "loves it".. said he immediately felt better due to much better sleeping and doesn't find wearing it a problem.    The above note on the sleep study also appears in a post by me on the ENT Community. I see a possible connection between AFig, Dreaming problems, and my yet to be diagnosed apnea.