Also, according to the AHA, continuous waveform capnography along with clinical assessment is the most reliable method of confirming and monitoring correct placement of an ET tube.
What is Waveform Capnography
Quantitative waveform capnography is the continuous, noninvasive measurement and graphical display of end-tidal carbon dioxide/ETCO2 (also called PetCO2). Capnography uses a sample chamber/sensor placed for optimum evaluation of expired CO2. The inhaled and exhaled carbon dioxide is graphically displayed as a waveform on the monitor along with its corresponding numerical measurement.
As an assessment tool during CPR, capnography can help the ACLS provider determine a number of things. It is a direct measurement of ventilation in the lungs, and it also indirectly measures metabolism and circulation. For example, a decrease in perfusion (cardiac output) will lower the delivery of carbon dioxide to the lungs. This will cause a decrease in the ETCO2 (end-tidal CO2), and this will be observable on the waveform as well as with the numerical measurement.
Normal ETCO2 in the adult patient should be 35-45 mmHg.
Two very practical uses of waveform capnography in CPR are: 1.) evaluating the effectiveness of chest compressions, and 2.) identification of ROSC. Evaluating the effectiveness of chest compressions is accomplished in the following manner: Measurement of a low ETCO2 value (< 10 mmHg) during CPR in an intubated patient would indicate that the quality of chest compressions needs improvement.
High quality chest compressions are achieved when the ETCO2 value is at least 10-20 mmHg.
When ROSC occurs, There will be a significant increase in the ETCO2. (35-45 mmHg) This increase represents a drastic improvement in blood flow (more CO2 being dumped in the lungs by the circulation) which indicates circulation.
For the intubated patient in cardiac arrest, quantitative waveform capnography is now considered the desired method for monitoring the quality of chest compressions and determining when the patient has a ROSC.
This video explains waveform capnography, it benefits, and various applications.
Orly says
If a pulse is felt and the person is ventilated through a breathing machine but the etco2 is sub 30 do we need to perform cardiac compressions? Or rely on the pulse thatan there is adequate circulation?
Jeff with admin. says
It is unlikely that you will be able to palpate a pulse before you see a rise in ETCO2. The sudden increase in ETCO2 is typically the first sign of ROSC and will be seen prior to being able to palpate a central pulse. If you see a rise in the ETCO2 finish the round of CPR and perform a pulse check.
If you cannot palpate a pulse then continue for another cycle of CPR. Then recheck the pulse. Also realize that the initial ETCO2 reading might be higher than normal (35-45 mm Hg) because of the accumulation of CO2 in the cardiopulmonary system during cardiac arrest.
Rely on the pulse check, but if ETCO2 is available, it can be used to assess CPR quality and monitor for ROSC.
Kind regards,
Jeff
Jennifer says
If we see a spike in etco2 is that enough to stop compressions and do a rhythm /pulse check? Or do we finish our round of compressions and check after our 2 mins as usual?
Jeff with admin. says
You finish the round of CPR and check the pulse after the two minute cycle. It can take time for the heart to begin to pump efficiently and completing the cycle of CPR helps to ensure that adequate circulation has been established. Kind Regards, Jeff
Sarah says
If we had a code situation and a physician was not present to intubate but we were able to deliver excellent ventilation so via BVM, could we attach the ETCO2 device between the mask and the bag to give an indication of our chest compression and ventilation adequacy, until such time intubation was able to take place ?
Jeff with admin. says
This is possible but the equipment to do this type of monitoring is fairly new, not in wide use, and under development. Here is an article about the topic:
Bag mask ventilation and ET CO2 monitoring
Kind regards,
Jeff
Eric Amistad says
Do we need to actively decrease EtCO2 to 35-40 during ROSC? Like bringing back 50 to 35-40? How do we ventilate? Do we increase the rate of ventilation?
Jeff with admin. says
An EtCO2 level of 35-45 indicates that ventilation is adequate. An elevated EtCO2 level is typically an indication of hypoventilation or increased metabolic activity.
If you are delivering a normal number of ventilations and your EtCO2 level is high then you would want to identify why the EtCO2 level is remaining high and treat that cause.
Here are a couple of articles that go a little deeper on the subject if you would like to read:
Waveform Capnography 1
Waveform Capnography 2
Kind regards,
Jeff
Sharon says
I have heard instructors state that the ETCO2 will show a sudden rise to 50-70 when rosc occurs and then decrease to 35-40. Is this accurate information?
Jeff with admin. says
It is likely that the ETCO2 may be higher than normal when ROSC occurs. This is because there is a buildup of CO2 in the lungs and body during the cardiac arrest when metabolic processes are not functioning optimally. Once ROSC occurs and the CO2 is washed out of the lungs with the reestablished metabolic processes the CO2 will drop down to the normal level of 35-40 mmHg.
Kind regards,
Jeff
Toban says
Since it is now considered standard of care, will waveform capnography be incorporated into the Megacode simulations?
Jeff with admin. says
Yes this is correct. For any scenario in which the patient is intubated, there will be questions about waveform capnography.
For the purposes of cardiopulmonary resuscitation, the patient must be intubated for proper measurement of ETcO2.
Kind regards,
Jeff
Steven Chadwick says
Does administration of bicarb during acls effect the ETCO2 ranges given for good compressions?
Just looking at it from a physio standpoint you would think you would get an increase in ETCO2 throwing off the ranges.
Jeff with admin. says
Bicarbonate given during CPR could potentially give a slight increase in the end tidal CO2. I do not think that it would be significant enough to give you a false reading of good or bad compressions.Kind regards, Jeff
Coty says
You won’t note any significant change (~5mmHG) but the big thing is recognizing when to give Bicarb and when not to. We no longer administer Bicarb for acidosis secondary to extended down time, now it’s usage is limited to tricyclic antidepressant overdose and suspected electrolyte imbalance. Studies have actually shown that when given IVP there is an initial decrease in pH due to cellular metabolism often lowering the patient’s pH below the threshold for sustainable life before the bicarbonate begins to slowly raise the pH, hence why it is now often referred to as a drip. In drip form this noted drop is not present.
Jeff says
It’s important to remember that the CV system does not function well in a severely acidotic state. Therefore, there’s nothing “wrong” with IVP of bicarb, however improvements in cardiovascular function are transitory as bicarb is rapidly metabolized. Anecdotally, IVP w/gtt probably achieves best results in my experience. Honestly, while I’m a “data driven” practitioner (RT) I’m not familiar with any well executed (randomized, blinded, controlled) trials which have looked at this.
Gail says
So before ROSC the waveform capnography ETCO2 will be 35-45mmHg (normal)?
Jeff with admin. says
That is correct. When ROSC occurs The end title CO2 Will go to normal range which is 35–40 5 mmHg. Kind regards, Jeff
Coty says
You’re not necessarily looking for an increase to norm range with ROSC. In my experience I’ve noted EtCO2 increases to around 25mmHG with ROSC. The important thing is to note the time of change, complete your round of CPR and then assess for pulse. If you have a perfusable rhythm and increase in EtCO2 with good capnography then chances are you have ROSC.
Jeff says
Agree – Please don’t focus on numbers; especially “normal values.” If someone is performing compressions CPR and your EtCO2 is 6; you switch practitioners and it’s 50, you now have effective compressions, (and likely need better ventilation). Furthermore, we will never magically see a return to normal values with ROSC for two reasons:
1.) ROSC may occur DURING compressions, and;
B.) It’s highly likely that ANY lab value is going to be “normal” after requiring CPR.
Kim says
I wish I would have discovered this site a week ago. My recert is this morning. I’ve learned more in the last 12 hours from your site than I did from the AHA book all week. I’ve written the URL inside my ACLS book cover for the next go round. Wish me luck for this morning!
Jeff with admin. says
Good Luck with your certification! Kind regards, Jeff
Michele Dembin says
Excellent information for ACLS recertification. A friend of mine said this was an excellent resource, and she was 100% correct.
Thanks,
Michele
Elaine12 says
It’s a great feeling whenyou understand the material. thanks
SEDIVA says
?
bakir1 says
Thanks Jeff! I never understood this until now!
GabrielMolina says
Excelente
Deepa George says
nicely explained
mongezi says
Nicely explained
anna says
Thanks.Understood better now.