Likely one of the top five advancements in EMS within the past decade or two has got to be the introduction and adoption of capnography. Hands-down, this valuable assessment tool has proven its versatility, validity and value on a number of scales.
But it’s often still misunderstood. Capnography still has many different connotations within our industry, from the colorimetric device to the number or the waveform.
Our job as educators, administrators and clinicians is to set the record straight. Capnography is the gold standard, and it starts with the waveform.
Just as the “graph” part of the word indicates, we want (and need) to be interpreting the waveform. From there, we can also get the number – end-tidal carbon dioxide value or peak expiratory pressure. Relying solely on the color change is outdated practice, something that should be No. 4 or 5 into the equation of advanced airway verification, certainly not No. 1.
Considering this development, let’s break down three EMS training scenarios where capnography is a must.
1. Dyspnea
Bob Page would tell us that “if your patient has a pulse and a problem, then you need a 12-lead,” and if they’ve got difficulty breathing, you need to “slap the cap!”
Along this line, let me emphasize this additional point: If you’re interpreting (or even obtaining or monitoring) a capnograph on your monitor, then you must print out the waveform!
In short, the capnograph is the airway equivalent of the 12-lead. You would never walk into an emergency department with a chest pain patient without a 12-lead EKG, and you should never walk into that ED with an airway patient without a printed capnograph.
Aside from lung sounds, what other tools do you readily have available to you that can help to diagnose (that’s right, diagnose) and treat dyspnea? What else do you have that can help to build your case for a certain treatment – an advanced intervention?
Let’s take wheezing, for example. Remember, not all that wheezes is asthma, so if you’re simply administering “just” a nebulizer to your wheezing patient, you really need to be asking yourself whether or not this is appropriate or enough.
If the waveform shows a sloping upstroke or a shark fin, then sure, an albuterol and ipratropium nebulizer is a good start. But if that waveform appears normal or has a sloping or steep downslope, then your nebulizer is exactly that – “just” a nebulizer. You need more power. You need CPAP.
Regardless of the exacerbation extent of your patient’s respiratory complaint, why not provide receiving hospital staff with the best information possible to help guide the patient’s overall treatment course? Interpreting the capnograph, in all dyspnea cases, provides you with the information you need – both graphic and numerical.
2. Altered mental status
Syncopal episode, seizure, stroke, hypoglycemia, narcotic overdose, pain management, behavioral sedation, sepsis – pick a scenario, any scenario, and capnography has an application.
SIRS criteria with an infection and suspected hypotension: Your end-tidal carbon dioxide number (obtained from the capnograph waveform) can help to build your case for sepsis.
A sleepy patient post-100 micrograms of fentanyl can have his or her ventilatory status monitored via livestream capnography evaluation, which is significantly more effective than watching the pulse oximetry value gradually decline.
Snoring respirations, diaphoresis and a blood sugar of 32 routes you toward the need for dextrose (ideally 10%) and warrants capnograph monitoring while you obtain IV access, provide supplemental oxygenation and consider the need for bag-mask ventilations or even glucagon administration.
Quite simply, if your patient’s ABCs are at risk, then monitoring his or her capnograph is a must.
3. Preparing for an advanced airway
Whether you’re working a scenario following the concepts of cardiocerebral resuscitation (CCR) or cardiopulmonary resuscitation (CPR), applying a nasal cannula with end-tidal monitoring capabilities and high-flow oxygen can accomplish two tasks:
- Increased supplemental apneic oxygenation.
- Ventilation/perfusion evaluation.
While you prepare your patient for endotracheal intubation or supraglottic airway insertion, providing increased supplemental oxygen can help prevent desaturation during your intubation timeframe. Also, monitoring the end-tidal carbon dioxide during this process can provide you with a better benchmark than what pulse oximetry may have to offer. After all, you can’t create carbon dioxide without ventilation and perfusion.
Once your patient is intubated, whether it’s in a cardiac arrest or respiratory arrest, this should be followed by auscultating for the absence of stomach sounds, then positive lung sounds, and then verified by a capnograph (waveform plus end-tidal numeric value) assessment, not simply by applying a colorimetric carbon dioxide assessment device. We need the waveform.
Capnography is not only the “wave” of the future, it’s the gold standard, both in the field and in the training room.
