Capnography

[firedoc5]

I think your question has been covered in legnth. Just get to learn your acid/ base balance and it'll all make sense. But I wouldn't waste time doing vents. if there is a problem with the cap device itself. Actually I hated using them. If you have them tubed, and the tube is placed right you'll know it.

[chbare]

I think your question has been covered in legnth. Just get to learn your acid/ base balance and it'll all make sense. But I wouldn't waste time doing vents. if there is a problem with the cap device itself. Actually I hated using them. If you have them tubed, and the tube is placed right you'll know it.

I have to disagree. All of the subjective methods of tube confirmation are unreliable. In addition, ETCO2 can provide us with crucial information about the hemodynamic status and in many cases, sudden changes in the patients condition may be noticed by the provider who uses continuous waveform capnography before a provider who does not use this tool. ETCO2 is also great to have on inter-hospital transfers where you have ABG results and can actually correlate the ETCO2 to the PaCO2. Remember, CO2 is not only an indicator of gas diffusion at the alveolar level, but it is an important indicator of cardiac output.

"-70-100 % of patients intubated with an ETT have PH and PCO2 changes in transport." 8th Annual SLAM 2006. If CO2 is such an important indicator of overall status, would it not be considered a sort of vital sign with intubated patients? If so, we would never transport somebody without checking their pulse and respirations frequently, why not ETCO2? I never knew how easy it was to screw somebody up when they are intubated; however, it can happen quickly and impact patient outcome.

Take care,

chbare.

[firedoc5]

ETCO2 is also great to have on inter-hospital transfers where you have ABG results and can actually correlate the ETCO2 to the PaCO2. Remember, CO2 is not only an indicator of gas diffusion at the alveolar level, but it is an important indicator of cardiac output.

"-70-100 % of patients intubated with an ETT have PH and PCO2 changes in transport." 8th Annual SLAM 2006. If CO2 is such an important indicator of overall status, would it not be considered a sort of vital sign with intubated patients? If so, we would never transport somebody without checking their pulse and respirations frequently, why not ETCO2? I never knew how easy it was to screw somebody up when they are intubated; however, it can happen quickly and impact patient outcome.

Take care,

chbare.

I was referring to the field with short term treatment. In my experience we usually had no greater time to a hosp. of more than 20min. Our main concern was to tube the patient, get adequate ventilations established, and try and get PaO2 up to normal or even high levels. If using or attempting to use a CAP and having problems with the CAP itself, then it can be a hindrance that can interfere with establishing sufficient ventilation. In short, it can potentially be something else that can get in your way. I'm not against it's use. If you've got it, use it if you want. Just don't let it interfere with getting ventilations started.

I agree on the long term where there is time for changes to occur, especially with a inter-hospital transfer. But even then you are still pulse and resp. frequently.

[chbare]

I can agree, that if you have total device failure, you will not be able to use it. However, I do not agree that you will know if the tube is in place. Inadvertent esophageal intubations are well known and documented. Simply using subjective assessment techniques without adding at least one objective method into the mix will set a dangerous precedent. I also say if you have the ability to monitor ETCO2 and waveform capnography, you SHOULD use it.

Again, it does not take long to alter CO2 in some cases. Respiratory alkalosis is documented in patients who have been intubated in the field. Simply looking at the pulse oximeter and skin color will not tell us about CO2. In fact, it will not tell us what the PO2 is. When we consider any condition that will shift the curve, the PO2/SAO2 difference can be quite profound. Remember, CO2 levels can tell us important information about the ventilatory status of our patient.

Perhaps we are on the same page; however, I want to be clear that I do not think using capnography should be optional if you have it.

Take care,

chbare.

[ccmedoc]

...would it not be considered a sort of vital sign with intubated patients? If so, we would never transport somebody without checking their pulse and respirations frequently, why not ETCO2? I never knew how easy it was to screw somebody up when they are intubated; however, it can happen quickly and impact patient outcome.

I have to agree with chbare on this and his other comments..If you have it then you should use it. Especially with intubated patients..long or short transport.

Perhaps we are on the same page; however, I want to be clear that I do not think using capnography should be optional if you have it.

Absolutely!! :thumbleft:

[VentMedic]

While I do agree capnography is important for IFTs, it should never replace physical assessment. I also argree with firedoc5 that a visual of the tube going through the cords should ensure the cuff is also below the cords. Breath sounds are still a good standard for placement below the cords and above the carina. Skin color and quality of pulses or BP are still important. Unless you have a thorough understanding of capnography and all of its many components, you could chase the wrong numbers or read too much into it especially if you have too little info to correlate with the numbers. If you are not accustomed to reading the wave forms, you again may read the wrong things into a situation if you are not watching the patient more than the monitor.

Just like the pulse ox, too much or too little can be read into the results especially with all the factors that can also affect ETCO2. Some of those listed below concern us more in the hospital, but if you do interfacility transport you must be aware of factors that can give less than optimal waves and normal numbers. This is especially true with some of the portable transport ventilators with single limb circuits and external PEEP/exhalation valves.

Sudden drop in etCO2 reading to close to zero :

Complete deconnection

Totally obstructed tube

Esophageal intubation

Complete malfunction of the respirator

Sudden drop in etCO2 reading to low value :

Partial obstruction

Leak in respirator system

Emboli (Air, Fat, Thrombus)

Exponential drop in etCO2 reading :

Pulmonary embolism

Sudden hypotension (blood loss, caval compression)

Cardiac arrest

Esophageal intubation (respiration of the stomach!)

Persistently low etCO2 without a good plateau :

Bronchospasm

Partial obstruction (kink in tube, cuff hernia)

Secretion in tube, respiratory tract

Discharge rate from capnograph too high

Breathing frequency too high (Children, tidal volume too small)

Persistently low etCO2 with a good plateau :

Large dead space (in respiratory tract) (Chronic Obstructive Pulmonary Disease, COPD)

Non-calibrated equipment

Pulmonal hypoperfusion with hypovolaemia and high positive pressure respiration

Gradual decline in etCO2 :

Hyperventilation

Hypothermia

Reduced systemic or pulmonal arterial perfusion

Gradual increase in etCO2 :

Hypoventilation (Leak)

Rising body temperature (malignant hyperthermia)

Absorption from external CO2 source (Laparoscopy)

Sudden increase in etCO2 :

Beginning of partial deprivation of blood supply

Injection of "Nabic" *(sodium bicarbonate)

Gradual increase in both base line and also etCO2 :

Rebreathing (valves, bypass, breath calcium, fresh gas flow)

Flattening out of the decreasing side (inspiration) and increase in the base line :

Defect inspiration valve with large counter/contrary flow

Increase in the base line and artifact between the single capnograms :

Defect expiration valve with rebreathing

Short dip in plateau

Patient fights against the ventilator

Leak at the cuff of the tube

Gradually increasing expiration side :

Bronchospasmus caused, for example, by COPD

Secretion in respiratory tract

Kink in tube

'Shoulder' in the plateau phase :

Uneven emptying of lungs (lateral positioning or surgery, lungs leaning on the thorax)

Source:

http://www.medana.unibas.ch/eng/amnesix1/lungmain.htm

[rogue medic]

One reason for the patients with unrecognized esophageal tubes is often the mistaken belief that the medic, nurse, or doctor, is so good that they don't need it. This is the most important EMS device available. Look at the cases from the Star-Telegram article. Nobody checked end tidal CO2 by any method. These killers are not people to copy.

Waveform capnography is the most important prehospital assessment of tube placement. It is far more important than the little piece of litmus paper used in colorimetry (color change CO2 assessment) or the hand held capnometry (number measurement without a waveform).

Capnography is not perfect. I have had a false positive that lasted much longer than 6 breaths with minimal change in pattern or numbers. This was a patient with a very distended belly following aggressive mouth-to-mouth prior to EMS arrival.

Although capnography is not perfect it is far more reliable than "I saw it go through the vocal cords." This is the lie that accompanies almost every esophageal tube. Whether it is a doctor, a nurse, or a medic telling the lie, it is a lie. The "Wandering Tube Foundation" has plenty of members who swear the tube was in the trachea. You can recognize them when tube placement is checked and they call out to other members - "WTF!"

Any magician will tell you "seeing is deceiving." Proper tube management and use of capnography will prevent this self-deception.

Not using capnography, instead relying on inferior assessments, when capnography is available is just bad patient care. Capnography is just a part of competent airway assessment.

Absence of sounds over the belly is probably the next most important assessment. Too many people want to hear the sounds over the lungs and waste time that could be spent ventilating the patient. The sooner you realize that the tube is in the wrong place, the sooner you can correct the problem. Listening over the lungs delays this. How many gurgling breaths over the stomach does it take to know that the tube is in the wrong place vs listening over the lungs again and again and again because you "just know you saw it go through the cords."

The EDD is not something that I have used, but it has good research to back it up. SLAM recommends its use.

Improvement in patient condition is also an important assessment. Chest rise, amount of belly rise, mucus membrane color changes, heart rate, . . . .

Obviously, you should have training on the use of capnography, if you are going to use it on patients. That is a no brainer, but having capnography and not using it is just bad medicine. You have the ability to accurately document that the tube is not in the esophagus, but you don't? Why would anyone do that?

Capnography will also let you know when there has been an important change in the patient's condition much sooner than any other assessment.

Through compressions and artifact capnography will quickly pick up on a change in cardiac output. What else does?

Capnography can be very helpful in assessing for capture with a transcutaneous pacer, when there is so much muscle spasm that you cannot tell if it is a pulse or a muscle twitch from the pacer.

Differentiating between CHF and pneumonia, so that the protocol monkeys can be discouraged from giving Lasix to pneumonia. Not that they should be giving it to anyone who doesn't have peripheral edema, but some doctors are a bit slow on changing their protocols to follow the research.

Differentiating between CHF and COPD exacerbations, so the same protocol monkeys are not following the wrong protocol.

When moving a patient with a tube that is hard to keep in place, capnography is the most important tool you can have. As long as your waveform does not change, assuming you have a good waveform, you know the tube is still where you want it to be.

At the hospital, the waveform is more reliable than direct visualization by the emergency physician.

And waveform capnography is cheaper than a lawyer. :-)

[VentMedic]

Nice post.

But, too many spend more time troubleshooting the machine before the patient.

It also still gives you a false sense of security as the tube's cuff migrates or stays above the cords if you didn't see it pass. The problem with accidental extubations is not assessing for proper placement of the tube in the airway . Is the cm mark appropriate for the height and neckline of the patient? You can still get a waveform with the cuff laying on the cords being used as an "LMA". After that, the tube is haphazardly secured. If I nickel for every tube that was placed by recipe and not by commonsense, assessment or cord marks, I would have been in retirement long ago.

No piece of equipment is going to magically correct imperfections in how one places or secures the tube. Nor, is it going to make someone who already lacks assessment and intubation skills any better. That has already been "discovered" with the pulse oximeter. I think those that have understood intubation and assessment have not had those experiences mentioned above when they get to the ED.

I'm not arguing against capnography but rather for a better educational system that fosters intubation skills before capnography is used as a crutch rather than a diagnostic adjunct.

[rogue medic]

But, too many spend more time troubleshooting the machine before the patient.

This is not to be encouraged. Capnography is there to assist with assessment of airway management. It is only one part of the full airway assessment, but it is the most reliable part.

It also still gives you a false sense of security as the tube's cuff migrates or stays above the cords if you didn't see it pass.

If I must choose between a tube that is placed with the cuff above the cords and an esophageal tube, that is an easy choice. If the tube is not through the cords and does not stay in place, capnography will let me know this more reliably and more quickly than any other method of assessment. The goal of airway management is ventilation, not intubation.

The problem with accidental extubations is not assessing for proper placement of the tube in the airway . Is the cm mark appropriate for the height and neckline of the patient? You can still get a waveform with the cuff laying on the cords being used as an "LMA". After that, the tube is haphazardly secured. If I nickel for every tube that was placed by recipe and not by commonsense, assessment or cord marks, I would have been in retirement long ago.

An LMA is an acceptable means of securing an airway. Anyone repeatedly attempting intubation, instead of securing an alternative airway is not providing patient care, but protocol care. Even if the tube is haphazardly secured, the capnography will let you know, better than any other method of assessment, if things change.

Since capnography is the most sensible part of airway assessment, the use of capnography must be what keeps you from collecting those nickels. Who's paying these nickels out, anyway?

No piece of equipment is going to magically correct imperfections in how one places or secures the tube. Nor, is it going to make someone who already lacks assessment and intubation skills any better. That has already been "discovered" with the pulse oximeter.

I am not a fan of gadgets, but capnography is the one gadget that is most important to EMS. Oximetry is rarely an assessment that is significant. The one true benefit of oximetry is recognizing covert hypoxia, which is not so common. Capnography does not make the person better at intubation, but better at assessing the placement of the tube. The person who lacks intubation and assessment skills should not be treating patients by ALS means. If the incompetent are allowed to treat patients, then the medical director is the problem.

I think those that have understood intubation and assessment have not had those experiences mentioned above when they get to the ED.

I think the research is quite clear on the value of capnography.

I'm not arguing against capnography but rather for a better educational system that fosters intubation skills before capnography is used as a crutch rather than a diagnostic adjunct.

Capnography is a diagnostic adjunct that is far more useful than a "National Registry mandatory phrase," such as "I saw the tube go through the cords." The one thing I do not want to hear is the recitation of a NR mantra when the patient needs an airway. The tubes that are in the esophagus are almost always accompanied by that NR monkey phrase.

Yes, we need to have medics much better educated. NR's teach to the test is the opposite of education.

Seeing the cords is nice on all of the easy tubes. What do you do when you can't visualize the cords? What do you do with your higher grade Cormack-Lehane views? Should you not use a bougie, since it is incompatible with seeing the tube go through the cords?

I have no problem with using crutches to manage the airway. LMA, King LT, CombiTube, BVM, . . . , are all crutches. Other crutches that I think are important to use are Bimanual Laryngoscopy, the bougie, placing the tube above the arytenoid cartilage (much easier to recognize in a difficult airway than any of the other structures), using suction, looking for bubbles in the liquid in the airway that is coming out faster than suction can manage, surgical cricothyrotomy, RSI, . . . . Crutches allow me to deliver better care, they are not an alternative to it.

If I want to know where the tube is, capnography is the most important assessment, but it is not the only assessment.

When I arrive at the ED and they pull the capnography tubing that they do not like, they are only demonstrating profound ignorance. The ED personnel would not do that in the ICU, but they are removing equally valuable equipment.

Someone should not be using any equipment unless properly trained. If your people are not properly trained in capnography, the problem is not the capnography, but the person who allows this to happen and the medical director who doesn't stop it.

[VentMedic]

People have also been intubating successfully for almost 4 decades now in prehospital without the use of an ETCO2 monitor. Not everyone is trained equally or has a good medical oversight in place. Not every service has the same tax base. Not everyone is doing RSI yet or even a lot of sedation. Not everyone is working in comfortable environments with lots of extra help to carry lots of equipment.

If your intubation skills suck, capnography is not going to improve that. It may not mean you are an incompetent provider but if the company thinks buying more tools is going to improve that instead of getting your skills up to par....

As I mentioned before, capnography does have its place. I am definitely not against it.

However, before you make blanket statements, you must take into consideration all the different levels of training and skills abilities as well as the frequency of intubation per month or even per year for different services. Sometimes one tends to get very self absorbed in their own perfect world that they can not see all the issues surrounding something as what you perceive to be as simple as capnography.

When I arrive at the ED and they pull the capnography tubing that they do not like, they are only demonstrating profound ignorance. The ED personnel would not do that in the ICU, but they are removing equally valuable equipment.

In both the ED and the ICU, it is used as a diagnostic tool and not an expensive tube sitter.

It will definitely be removed in many ICUs across the country if that patient did not warrant ETCO2 monitoring. Experienced ICU personnel do not need another piece of equipment to add to all the other bells and whistles just to tell them a tube is here or there. Since they have ventilators, CR monitors and educated professionals at bedside, they know where their tubes are. They also have diagnostic tests to tell them what is going on with the patient. If there is an ETCO2 on the pt, the pt may be a difficult wean or they are expecting the lungs to worsen or maybe improve or predicting mortality by the deadspace ratio. It also does not have to be used for simple ventilator weans.

So no, these people in the ICUs or EDs may be not ignorant, just better educated and more confident in their training and skills as well as their adjuncts which you may not be aware of.

As high tech as many ICUs are, they also know they may have to triage out their less needed electrical appliances in a disaster. Quess where the ETCO2 monitor ranks as must have equipment by experienced ED and ICU personnel?

Someone should not be using any equipment unless properly trained. If your people are not properly trained in capnography, the problem is not the capnography, but the person who allows this to happen and the medical director who doesn't stop it.

The problem starts at the "training" institution and continues throughout the medical oversight.

I have used capnography in various situations many times over the past 25 years. I have learned its limitations as with any technology.

It sounds like you are putting alot of faith into a piece of equipment that can fail you. The wave may not change at the slightest movement. I listed other variables that also mimic similar wave patterns.

What are you going to do the day your piece of equipment doesn't light up?

Are you going to pull what could be a perfectly good tube if your monitor still says flat line because you don't trust your own self with watching it "pass through the cords". Or, will you ignore the patient and "work the machine" instead?

Should you not use a bougie, since it is incompatible with seeing the tube go through the cords?

Are you not using another assessment skill and sense of "feel" for this procedure and relying a little on your human qualities to do this?

Just curious, who sold you on capnography and who trained you? How long ago?