A question about pulse ox readings.

[ERDoc]

Good havin ya around, Doc.

You dont happen to have AIM do ya? I wanted to pick your brain a bit if youve got a sec...

No I don't. Shoot me a PM. I'll be aorund.

[DwayneEMTP]

Thanks guys, that's awsome.

And Doc, that's interesting about pulse ox being so valuable! I've seen it argued on here that it should be removed from ambulances..

Perhaps that is because of misuse? Cold hands, poor circulation, nail polish, etc. not being taken into consideration? Sorry, I can't remember the arguments, it just seems that after your comments that misuse would be the most likely argument against them...

Thanks again!

Dwayne

[ERDoc]

Thanks guys, that's awsome.

And Doc, that's interesting about pulse ox being so valuable! I've seen it argued on here that it should be removed from ambulances..

Perhaps that is because of misuse? Cold hands, poor circulation, nail polish, etc. not being taken into consideration? Sorry, I can't remember the arguments, it just seems that after your comments that misuse would be the most likely argument against them...

Thanks again!

Dwayne

I'm not making an arguement for or against them in the ambulance. It should help you in your assessment, but not be the end of your assessment. They do have real use in the hospital.

[DwayneEMTP]

Got it...Thanks Doc.

Dwayne

[OzMedic]

Pulse Ox readings are used as a crutch for providers that cannot properly evaluate a pt. If their lips are blue I am betting that they are going to need oxygen. Pulse Ox is going out the doors in hospitals too. In acute care settings Co2 output is measured and is a better way of assessing how much oxygen the patient really needs.

I agree with you, anyone who makes a post like this should not have it! :roll:

[akroeze]

I've seen medics say "Oh, you're breathing is fine! Look at your oxygen level! We don't need to put this mask on you"

(Not an exact quote)

THAT is the real danger with SpO2.... improper use.

[windsong]

I've seen medics say "Oh, you're breathing is fine! Look at your oxygen level! We don't need to put this mask on you"

(Not an exact quote)

THAT is the real danger with SpO2.... improper use.

That happened to me, when the medics came to my house, they said my sats were fine, but, when I got to the ED, the nurse there was pissed at the medics. Having asthma is nothing compared to someone with copd, because I guess they look and sound alot worse than I did.

So I guess judging from this, why worry, it's really nothing, right?

[VentMedic]

I am very tough on my students when they try to give me numbers from technology before "What the pt looks like and what iis he/she is telling you?"

COPDs that are still smoking will have a COHb of 6 - 12%. Thus if the SpO2 is 95%, O2 is not readily given even though the actual SaO2 is 83-89% and pt is short of breath. "They can't be short of breath...their SpO2 is 99%!" If they smell of smoke..yes they can, even with second hand smoke. Some signigicant others will have close to the same COHb if one is always smoking close by.

Patients on nitrates carry a higher MetHb, again presenting a higher SpO2.

And, the anemic pt who's SpO2 is 100% but their Hb is 6. Do you know what their O2 carrying capacity is?? I can only hope all Hb stay well saturated until definitive treatment. Yes, so one bleeding out may have an SpO2 of 100%, their Hb is laying on the ground. Would you "titrate" the oxygen on this patient?

The pts with higher MetHb and COHb will also not look "blue". Their Hb is still saturated although not with O2. Even regular blood gases will not give you the accurate picture until cooximetry is done (hopefully with the blood gas but is not always ordered in the ER). Then again there are other factors determining the Hb's affinity for the oxygen. But that is a whole different matter in itself that ICUs have to worry about daily on some patients.

COPD pts who are air-trapped, low on Hb and high on COHb can be very hard to "titrate by SpO2".

If an EMT or Paramedic can not readily identify "shortness of breath, trauma", then ..... Even in the hospital setting we do not rely on SpO2 solely. Perfusion, medication, lighting, smoking, temperature...just to name a few can skew the readings. Do you know how much of a laugh the ER/ICU staff gets watching an EMT or EMT-P totally focused on "getting a sat" on someone who hasn't had good perfusion below the elbows in 20 years..."it was a 100% a minute ago" as they're coding the patient.

Of course this doesn't just happen in EMS, hospital workers get caught in their technology and forget to "assess" the pt.

The pulse ox can be the last sign to deteriorate on an air-trapped asthmatic. The trapped air will actually give a "PEEP" effect for a short time thus increasing oxygenation slightly. This is also what gives the BP some instability in asthmatics. Many asthmatics will actually desat for a period when they start to open up. Only by "looking" at the pt will you know if they've turned the corner for improvement OR have reached the "last sign to deteriorate" part.

The hospital/ambulance lights, muscle tremors, bed vibration on pneumatic beds, blood, dirt, metalic flecked nail polish (good pleth but is it counting the metalic flecks?)...all could can give a false reading. I can always take the oxygen off...I can't replace oxygen starved cells in the brain.

Thus, the number on the pulse ox can mean very little by itself.

Goals are good EMERGENCY CARE and to to save yourself from being a topic of laughter in the ER.

[OzMedic]

I am very tough on my students when they try to give me numbers from technology before "What the pt looks like and what iis he/she is telling you?"

COPDs that are still smoking will have a COHb of 6 - 12%. Thus if the SpO2 is 95%, O2 is not readily given even though the actual SaO2 is 83-89% and pt is short of breath. "They can't be short of breath...their SpO2 is 99%!" If they smell of smoke..yes they can, even with second hand smoke. Some signigicant others will have close to the same COHb if one is always smoking close by.

Patients on nitrates carry a higher MetHb, again presenting a higher SpO2.

And, the anemic pt who's SpO2 is 100% but their Hb is 6. Do you know what their O2 carrying capacity is?? I can only hope all Hb stay well saturated until definitive treatment. Yes, so one bleeding out may have an SpO2 of 100%, their Hb is laying on the ground. Would you "titrate" the oxygen on this patient?

The pts with higher MetHb and COHb will also not look "blue". Their Hb is still saturated although not with O2. Even regular blood gases will not give you the accurate picture until cooximetry is done (hopefully with the blood gas but is not always ordered in the ER). Then again there are other factors determining the Hb's affinity for the oxygen. But that is a whole different matter in itself that ICUs have to worry about daily on some patients.

COPD pts who are air-trapped, low on Hb and high on COHb can be very hard to "titrate by SpO2".

If an EMT or Paramedic can not readily identify "shortness of breath, trauma", then ..... Even in the hospital setting we do not rely on SpO2 solely. Perfusion, medication, lighting, smoking, temperature...just to name a few can skew the readings. Do you know how much of a laugh the ER/ICU staff gets watching an EMT or EMT-P totally focused on "getting a sat" on someone who hasn't had good perfusion below the elbows in 20 years..."it was a 100% a minute ago" as they're coding the patient.

Of course this doesn't just happen in EMS, hospital workers get caught in their technology and forget to "assess" the pt.

The pulse ox can be the last sign to deteriorate on an air-trapped asthmatic. The trapped air will actually give a "PEEP" effect for a short time thus increasing oxygenation slightly. This is also what gives the BP some instability in asthmatics. Many asthmatics will actually desat for a period when they start to open up. Only by "looking" at the pt will you know if they've turned the corner for improvement OR have reached the "last sign to deteriorate" part.

The hospital/ambulance lights, muscle tremors, bed vibration on pneumatic beds, blood, dirt, metalic flecked nail polish (good pleth but is it counting the metalic flecks?)...all could can give a false reading. I can always take the oxygen off...I can't replace oxygen starved cells in the brain.

Thus, the number on the pulse ox can mean very little by itself.

Goals are good EMERGENCY CARE and to to save yourself from being a topic of laughter in the ER.

Great Post and I agree with all that you say. I think that we need to look at this issue from a couple of perspectives. In reality, should every EMS provider that has access to a SpO2 monitor be educated to the above level before they use it?........ I think so yes, however, to understand the above and interpret SpO2 readings in the context of each patients presenting condition is another matter. From what I understand about the sad state of EMS education in the US there is not much point in learning the above info if the EMT/Medic does not have the background anatomy/physiology/pathophysiology knowledge to put it to use. Does this mean SpO2 should be reserved for clinicians that can interpret the values?........ Maybe not. The fact is that EMS providers of all levels are performing all kinds of advanced interventions (rightly of wrongly) on these patients before they reach hospital or are backed up by ALS of a higher level. As we all can testify at times, the patient that we wheel into an ED may as well be a completely different person to the one that we were first presented with. The ED nurse then rolls her eyes and makes some comment like I thought you said this person was sick, in extremis etc. Then the poor ER doc has to come along and make sense of the whole issue and try and decipher the clinical picture that he is presented with compared with the handover/runsheet from the EMT's (which let's face it can be worthless depending on who gave it and who took it). An initial room air SpO2 value on the runsheet may assist the ER doc in some way to interpret what is going on with the patient and what to do with them now. I guess the point of what I am saying is yes SpO2 can be dangerous when wrongly interpreted by poorly educated EMS personnel. However, it is an easy, safe, non-invasive measurement of a value that MAY be of value to a clinician when they interpret it later on.

By the way Vent, you say "you can always take oxygen off" and once again I agree with you as I do it all the time, but how often do you see it done in EMS and how often do you see it used inappropriately?

[JPINFV]

Youre also correct that the under reduced oxygen saturation, the body's production of energy -- ATP -- through the Kreb's cycle is slowed down. The Kreb's cycle is a process of producing energy using oxygen, called aerobic metabolsim. When the body is short on oxygen, it it is unable to use the Kreb's cycle and must use an anaerobic metabolsim (that is, "without oxygen"). The main producer of energy in this case is the process of glycolosis, which is basically the breakdown of sugars in order to produce energy. This method is WAY less efficient (something like 30 times less efficient) at producing ATP compared to the Kreb's cycle, and at the same time an offproduct of the cycle is lactic acid. This is what causes the burning sensation in your muscles when you are exerting yourself completely. Long term produciton of this acid causes problems in and of itself, not to mention the fact that you are producing less energy as well.

Close, but the majority of ATP is produced in the Electron Transport Chain (32 ATP/glucose), not by the Krebs (2 GTP/glucose) or Glycolysis (net of 2) [note, ATP numbers are for each glucose that goes through aerobic respiration. Glucose only enters during Glycolysis]. That said, the majority of NADH and FADH2 which runs ETC is produced during Krebs. This is why, for example, you get a "false" SpO2 reading for patients suffering from cyanide poisoning. ETC is disrupted in the cell causing aerobic respiration to halt. While the Sp might really be 100%, the body just can't use the oxygen anymore.