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.
pijush says
What is imCO2, and what is its significance in the waveform.
Jeff with admin. says
imCO2 means (inspired minimum CO2). The end of inspiration on the capnography waveform is referred to as phase 1 and represents dead space gases. If you notice that the waveform baseline is elevated it can mean a couple of things. The two most common are rebreathing CO2, and contamination of the capnometer. First, ensure that the patients not rebreathing CO2. Second, trouble shoot capnography sensor and replace if contaminated. Here’s a great resource for learning about PetCO2.
anna says
Does the Joint Commission now have a standard that addresses the use of end-tidal co2 monitoring in intubated, sedated patients?
Jeff with admin. says
As far as I know, the Joint Commission has no standard that addresses ETCO2.
Kind regards,
Jeff
sepea says
I would have loved to see this video but could not hear a single word
Jeff with admin. says
I checked on the video and the sound seems to be working ok. There are a couple of things you might try. On the actual video screen in the lower right-hand corner there is a volume control This may have been muted. Also your own PC may have muted. You might double check those settings.
Kind regards,
Jeff
nint says
The video worked on my iPad. Excellent.
bgriggspeacock123 says
thanks this explains a lot
Terry says
When using Capnography in an arrest situation how often should it be documented on the code blue record? Is there a standard?
Chris with admin. says
There is no set standard but typically it should be recorded at a minimum at the end of each cycle of CPR (every 2 minutes)
Kind regards,
Chris
Laura says
Since we know that ETCO2 levels consistently below 10 during CPR (“with proper ventilatory rates of 8-10/min”) can be a good indicator of poor viability, it is good practice to print out a waveform if it’s included on your monitors. Therefore, at the 2min mark, when you stop COMPRESSIONS to evaluate the patient’s rhythm, continue ventilations and print a strip (if your equipment allows this)…this strip will demonstrate the patient’s underlying rhythm along with the ETCO2 reading and a capnogram hopefully demonstrating appropriate ventilation. Thus, if/when the code is called due to poor prognosis/outcome, you have proof that you have done everything appropriately and effectively and that despite your best efforts this patient was not going to improve. (information obtained from physio-control’s university course on waveform capnography)
Susan says
If ETCO2 levels are consistently < 10 mmHg it seems there has not been adequate compressions delivered. Totally agree with proper ventilation rates (and volume for that matter) during the event to keep intrathoracic pressures ideal for venous blood return, but it is the ability of the rescuers to deliver excellent compressions to enable the proper gas exchange to achieve appropriate ETCO2 readings. Poor viability related to low end-tidal is related to poor compressions and low CO so I don't think this will prove everything was appropriate – might just be hard to explain why the compressions were not adequate along with the excellent ventilatory effort…
narkose says
If you palpate the endotracheal cuff upon inflation,
you have precluded its placement in
either the esophagus or mainstem bronchus.
Easy to feel – even on resusci-Annie.
Try it & do not fret about high tech gadgetry.
Ali B. says
You must ellaborate on this narkose…never heard of this technique.
frober30 says
Wouldn’t rely on this. Good luck with a 500lb pt.
Josegimenez says
Excelent
Janelle says
Are we supposed to intubate when the patient is in the hospital during ACLS or wait until ROSC? I was taught that the new thinking is not stop compressions to intubate but cannot find any rules regarding such in the ACLS book.
Jeff with admin. says
There is no set answer to this question. The decision to intubate should be based on clinical judgment and experience of the emergency team that is working. I have seen intubation occur more often after ROSC. Recently since implementing rapid response teams, I have seen intubation occurring in the pre-arrest setting so as to thwart an arrest.
Making the decision to intubate can be difficult because chest compressions must be stopped and the intubation process can be very time consuming. There is no easy answer.
Kind regards,
Jeff
Rach says
Why do chest compressions have to stop? Chest compressions don’t really affect visualization of the vocal cords at all! I have intubated my last 4 codes while compressions were being performed by both another medic as well as by an Auto Pulse. Try it! You may be surprised.
Jeff with admin. says
Thanks for the feedback. I definitely will pass this on to providers who intubate regularly.
Laura says
I agree completely with Rach! All of our pre-hospital paremedics go through extensive training and our protocols clearly state that we will not stop compressions to intubate (we are currently at about a 78% success rate through compressions). If your providers are not experienced or confident enough to intubate through compression they need more practice and simulations.
Waveform capnography is the gold-standard for monitoring CPR quality and determining patient viability during CPR…however, if providers are unable to intubate without detrimental effects of the patient, you can use capnography with BVM ventilations (just not as reliable/effectve).
Susan says
Totally agree, Jeff. If the code is spontaneous V-fib on a POD 3 bypass patient shock and move on – just like with an ICD they won’t have suffered much hypoxia so restoring the rhythm quickly and deciding what precursed the v-fib (electrolytes, volume, etc.) will be paramount. On the other hand, the patient who has been bradying down and is discovered in PEA with a slow response is most likely hypoxic and will not respond until the airway is secured and oxygen restored.
Jeff with admin. says
Susan, thanks for the input. Kind regards, Jeff
Susan says
Isn’t it true that the only reason we stop compression to provide breaths in the first place is to avoid bagging emesis, blood, etc. into the lungs? Async CPR is commenced with the advanced airway in place when there is no risk for creating aspiration – it would always be better not to stop due to the loss of coronary and cerebral perfusion during the pause in compressions. Once again, on an asphyxial or hypoxic scenario it would be essential to get the O’s on board; otherwise, especially in witnessed arrests shock and high quality compressions are paramount to ROSC and survival. Thanks for the input
jonathanjung says
What is the normal/good value of ETCO2 during compressions/advanced aw at 1 breath/6-8sec?
Jeff with admin. says
12.5-25 mmHg. See pg. 69 of the AHA ACLS provider manual.
Kind regards,
Jeff
greertm says
Would have loved to have viewed the video because I would like to understand better. Unfortunately, the volume was barely audible.
Thanks,
Thomas Greer, RN
Nashville, TN
Jeff with admin. says
You may want to view the waveform capnography video on another computer. I have never had anyone complain about not being able to hear the video.
Kind regards,
Jeff
gary crain says
I am wondering how accurate are petco2 values when compared to abg co2 levels? What would petco2 values become in a pt who is over- ventilated say on an assist control mode. I have used petco2 a couple of times in transport with our monitor, and the values don’t seem to correlate with recent abgs
Chris with admin. says
Typically there is a 4-5 mmhg difference with Petco2 being the lower value. As long as the physiologic dead space is within the normal range, there should be good correlation between the PetCo2 and the PaCo2. When physiologic dead space increases, the difference or gradient between the PaCo2/PetCo2 will be greater. Over ventilation with shallow breaths will increase physiologic dead space leading to elevated PCo2 and low or normal PetCo2.
Regarding ACLS, PetCo2 is reliable to detect ROSC and quality of CPR.
Kind regards, Chris
Greg Morris says
We are looking to purchase an EtCo2 device that is very small and inexpensive. The device only gives a numeric EtCo2 value and respiratory rate but does not have EtCo2 waveform. Will a numeric EtCO2 value be sufficient for determining effectiveness of chest compression and identification of ROSC?
Thank Greg
Jeff with admin. says
Yes, the machine that only has the numeric readout can be sufficient and effective for identification of ROSC if those who are using it know how to us it properly.
Proper and regular training are essential for this type of equipment to be used effectively.
As these devices become more the standard of care, I’m sure that they will get cheaper and more user friendly, but proper and regular training will still be of utmost importance.
Kind regards,
Jeff
pratibha.varma says
Thanks CM Jack.
Very well explained.
Untill now I knew of only the left shift phenomenon.
Now everything is crystal clear, scientifically.
pv
JayB says
I just started in an ICU and during a code the heart rate wasn’t picking up on the monitor and it was difficult to find a pulse, however the patient still had adequate end tidal. Does that mean the patient is still pulsating?
Jeff with admin. says
It would be hard to determine without seeing the waveform, but if the waveform was appropriate and the number continued read 35 to 40, I would try to palpate a carotid pulse. If unable to find a pulse within 10 seconds, i would resume CPR and try to palpate a pulse while CPR was in progress. That would help me to confirm that I have a correct location. Was there a particular reason why they could not find a pulse? Obesity can make it very challenging to asses pulses.
Kind regards,
Jeff
JayB says
The patient was morbidly obese and the at the time the code was initiated one of the leads were off. Thanks for the advice!
jonas says
Hi Jeff! This is very helpful i just want to know the difference between Waveform Capnography and the PetCO2?
as stated above, your doing good compressions if you have between 10-20 PetCO2, but what if its 35-45mmHg? is that ROSC?
so it means the NORMAL range of PetCO2 while doing compressions should be 10-20mmHg, then the NORMAL range for ROSC is 35-45mmHg…(stop doing compressions)
Jeff with admin. says
Waveform Capnography is another name for Monitoring PetCO2 using a waveform monitor readout. PetCO2 of 35-45 mmHG would indicate ROSC. If you see a PetCO2 of 35-45 when using waveform capnography you may assume ROSC. If you see a PetCO2 of 10-20 then you are performing effective chest compressions.
Kind regards,
Jeff