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.
jasper57 says
Passed….see you in two years.
Thanks so much,
JTJasper
Andy says
Excellent article and comments. A special population to consider on this topic: LVAD patients. Most LVAD patients will not have a palpable pulse, even with adequate perfusion + A&O x3. (The continuous flow pump drowns out the weak heart function). We rely on auscultating for the “hum” sound of the pump and a doppler blood pressure greater than 50. Trouble for EMS is I do not know of any rigs that carry dopplers. Maybe this is something that will change in the future. Without a doppler we rely on cap refill to assess for adequate perfusion. If a LVAD patient has pump sounds and good cap refill, they don’t need chest compressions. But when in doubt, start chest compressions.
Jeff with admin. says
Thank you for the feedback. That is good to know. Kind regards, Jeff
Marc says
Chest compressions with an LVAD are contraindicated given they can cause dislodgement of the LVAD from the major vessels and the heart. It’s recommended to compress the abdomen instead or only do chest compressions as a very last resort in this scenario. If you disrupt the continuity of the circuit, the patient won’t make it regardless.
Danielle Hawke says
We are a hospital-based EMS service with LVAD placement (Heartmate) at our home hospital. Per the surgeon, dead is dead. We will perform chest compressions on an LVAD patient who is unresponsive, apneic (or gasping), and the pump is not audibly running, per a specific LVAD protocol. He adds the risk of dislodging a VAD “I put in” is very low if compression depth is kept at about 2 inches or less in adults. We use ZOLL’s Stat-Padz to monitor depth during all arrests, so this is an achievable goal. Marc is correct in that tearing the vessels/dislodgement is certain death. So, we use kid gloves with these patients and monitor depth very closely, but if the pump is not running and the heart is not pumping, they are dead unless we do something about it.
Karen Risley says
Hi. As the only RRT( 40 yrs experience, only 3 here) at a small community hospital I am having trouble convincing our EMS that during resuscitation one will not get the “normal” 35-45 ETCO2 during a cardiac arrest situation. While I am bagging the patient, they will routinely come over and say ” slow down” if the ETCO2 is in the twenties, bagging at a rate of 10 bpm While I will show them your column, any other advice?
Another problem is, they will always expect me to place the CPR in progress patient on the vent which I politely decline. Has something changed in the last 3 yrs that I have missed ?
Thank you.
Jeff with admin. says
A patient should not be placed on a ventilator machine while CPR is in progress. Manuel use of bag mask ventilation is used for best practice and recommended by the AHA.
If ROSC occurs the vent can be used.
Kind regards,
Jeff
Aj Torres says
Why do we keep Co2 just below normal 35-40 instead of 35-45 post arrest?
Jeff with admin. says
This is done in an effort to reduce the chances of hyperventilation. Keeping the CO2 at a low normal will help ensure that the patient is not being hyperventilated.
Kind regards,
Jeff
Mike says
The 2015 ECC guidelines for respiratory care post arrest recommends: “maintaining EtCO2 of 30-40 or PaCO2 of 35-45 may be reasonable.”
clarissa says
If the patient is being monitored for ETC02 during a code. Do you still stop chest compression to assess for pulse?
Jeff with admin. says
At this time, the cardiac arrest algorithm does not replace the pulse check with any other form of assessment to determine ROSC.
You would still stop chest compressions and assess for a pulse.
Kind regards,
Jeff
Riviraj Warnakulasooriya says
Hi Jeff
Could cardiac arrest patients shows capnography over 40 with active CPR but still they are dead ?
Jeff with admin. says
No. If a patient is clinically deceased then they cannot have a end tidal CO2 level greater than 40 mmHg. With high-quality CPR you can expect a end tidal CO2 level around 20 mmHg.
Kind regards,
Jeff
brandon says
What are the reasons that we would get a reading above 30 while doing cpr? We had a patient go into arrest, tubed and ventilated and were getting readings 35-60 during CPR but we felt no pulse. They were in PEA. we worked them for 30 minutes. Multiple people checked multiple locations for pulses because we couldn’t believe it. We checked heart tones and heard nothing. When we stopped doing CPR, the numbers fell below 10. we were always told we’d never get numbers above 25 if we were doing CPR. is this incorrect information? what’s your thoughts on this?
Thanks so much
Jeff with admin. says
This could have been caused by a heart that was in complete failure but a body system that still had and intact metabolism. In other words, everything was working except for the pump.
Your patient’s metabolic processes were intact but his heart was not working. When you provided your patient with high-quality chest compressions and he was being adequately ventilated, this resulted in a close to normal ETCO2 unless chest compressions were stopped.
I have seen this happen one time before. It sounds almost like the same scenario. We had a normal ETCO2 as long as we continue chest compressions. After 45 minutes of chest compressions, it was determined that this guy’s heart just was not going to start and the wife decided to stop efforts for resuscitation. This patient had complete heart failure, but it was just a bad heart. The rest of his body was still working relatively well. He had a long history of heart problems.
Kind regards,
Jeff
Troy says
Thank you for this answer. The same thing happened during CPR in my ambulance yesterday. We were seeing ETCO2 between 50-80. We achieved ROSC 2 times, but the Pt’s heart finally gave out at the hospital. The ETCO2 was the topic of conversation last night, and it was driving us nuts.
Jason says
I just got on an ambulance with portable ultrasound and twice in the last month have pulled it out on a pt that medics could not feel a pulse during PEA and sure enough there was cardiac activity. We got both pts to the hospital without feeling a pulse just relying on ultrasound and end tidal and both pts made it out of the ed and to the icu with stable ROSC. Point is take a gamble with end tidal and a strong PEA and get them to the hospital.
Jeff with admin. says
Thanks for sharing that Jason. Very interesting account.
Kind regards,
Jeff
Kyle Lonesky says
Our department has started using Dopamine in early PEA pts during a code. It may not have truly been PEA but only appeared to be because we were not able to feel the pulse due to low BP. We have also been using waveform capnography during our codes because along with normal range numbers or a significant spike in numbers, a true waveform can only occur when there is ventilation (autonomic or assisted) and cardiac output to cause gas exchange for the capnography to read.
Michelle says
Do you recommend using an ETCO2 monitor during a code when ventilation is being performed with a BVM?
Jeff with admin. says
In the situation when there is no endotracheal tube in place, using ETCO2 monitoring is very difficult and has possibilities for being very in accurate. Until better monitoring treatments are available for ETCO2, endotracheal intubation provides the best method for monitoring.
Kind regards, Jeff
Mduduzi Mbuyisa says
An ETCO2 above normal range (35 – 40), what would it mean? And if it is a problem, what should be done?
Jeff with admin. says
An ETCO2 of 35-45 mmHg is normal. It means that the cells of the body are producing CO2, and that the CO2 is been exhaled with ventilation.
It is a good thing and this should be maintained.
During cardiac arrest, if this value is seen then it means that return of spontaneous circulation (ROSC) has occurred.
Kind regards,
Jeff
Natalie L says
Is the reason that CPR-generated EtCO2 (15-20mmHg odd) is lower than usual circulation EtCO2 (35-45mmHg) because the body is in anaerobic cellular respiration or because the venous content of CO2 is less or none of the above? Has it anything to do with VQ mismatching or increased dead space?
Jeff with admin. says
It has everything to do with v/q. Cardiac output is only 25-50% of what it normally is with CPR. So we would anticipate a drop in CO2 production. The higher the co2 the better the cardiac output. Kind regards, Jeff
Elaine McKinney says
Good reading and great video
Krysia says
If you notice a spike in ETCO2 during arrest, should you stop to check for a pulse, then continue with ROSC care, or continue cpr until the next rhythm check?
Jeff with admin. says
You will continue CPR until the next rhythm check. This ensures that the heart is given time to fully begin to perfuse blood again. I can take several minutes for the heart to fully recover and to achieve a sufficient ejection.
Kind regards,
Jeff
Shaz says
Is oxygen saturation a good indicator of adequate chest compressions , if you have a saturation of >94 can you assume you are doing effective CPR and therefore perusing peripherally?
Jeff with admin. says
Oxygen saturation will not be an effective way to determine the effectiveness of chest compressions. This is because it is very unlikely that you will see an oxygen saturation any where near even 90%.
I have helped with many codes, and I cannot recall a single person that was experiencing cardiac arrest and the oxygen saturation greater than 70%.
If you do not have a way to monitor ETCO2 (waveform capnography) then having someone visually monitor the chest compressors while they perform CPR is probably the best way to gauge effectiveness.
Kind regards,
Jeff
Michelle says
If a patient with a trach goes into arrest and Co2 detector does not provide a reading does this confirm the pt has been dead for a while?
Jeff with admin. says
This confirms one of 4 things. 1. The trach is obstructed and needs to be cleared. 2. The patient is not breathing. 3. If this lack of a CO2 reading is occurring with CPR and the trach is not obstructed, it means that there is no exchange of CO2 which would indicate complete cardiopulmonary failure (no gas exchange). or 4. The CO2 monitor is not functioning properly. It is not likely that you could accurately determine how long a patient had been in cardiopulmonary failure.
Kind regards, Jeff
Brenda says
Could it mean the intubation tube is in the esophagus instead of the airway if you don’t get a CO2 reading?
Jeff with admin. says
yes, you’re absolutely correct. Thanks for pointing out that I did not include this reason in my reply. The reading probably would not be zero, but you definitely would not see a waveform and the reading with be extremely low.
Kind regards,
Jeff
davedani777@gmail.com says
usually within how many hours the ETCO2 will return to 35-40 in ROSC.
Jeff with admin. says
When return of spontaneous circulation (ROSC) occurs, the ETCO2 should return to normal within 0-120 SECONDS.
This is why you finish a cycle of CPR before performing a pulse and rhythm check even if there is a change in ETCO2.
It may take a few moments for the heart to reestablish effective cardiac output.
Kind regards,
Jeff