Asthma Assessment Using Your Most Important Tool: The Power of Observation

Assessing a patient having an asthma attack can be complex. When a patient has audible wheezing and can’t speak, we know they’re in severe distress. There are other times the patient may not realize their own level of distress. There are subtle signs and symptoms that may predict increasing severity or the potential for catastrophic outcome. Assessment and re-assessment are the primary drivers for treatment, and the course corrections we need to implement when they are ineffective.

One of the most confounding circumstances from the COVID-19 pandemic regarding patient presentation had to do with severity. Patients were found at home—who may have been sick for a week—tachycardic, tachypneic, cyanotic, with grossly abnormal pulse oximetry readings. Patients we expected to be unconscious or with a decreasing level of consciousness, would walk outside and meet us at the curb and have full conversations with us. If this was an asthma patient with sudden onset of distress, without rapid intervention we might gear up for intubation and possibly CPR.

Pulse Oximetry

We’ve all heard the phrase “treat the patient, not the monitor.” This is especially true when evaluating the readings on a pulse oximeter. The pulse oximeter is a fantastic tool, but it has limitations. First what is the reading on room air? This is a crucial baseline measurement. Second what does the pulsatile waveform look like? Does it represent a normal, full signal, or does it indicate low perfusion? If it indicates low perfusion that’s an indicator that we shouldn’t put as much confidence into the reading we are obtaining.1-2 In this case where we have a low perfusion waveform if the reading is normal, it may actually be low. If it’s low, it may actually be lower than what appears on the monitor.

There is a lag time with the pulse oximetry reading between what the pulse oximeter is reporting and what is happening at the arterial level. It may be anywhere from 17 seconds to 5 minutes. This makes tracking and trending difficult at best. How well did the patient respond to supplemental oxygen? Is that 88% reading on room air going down further?

Skin Pigmentation and Signs

A study from more than 20 years ago showed skin pigmentation may interfere with readings and give the appearance that patients are “better oxygenated” than they are.3 Tragically this was a problem during the beginning of COVID, where we sent patients home with pulse oximeters to perform home monitoring. Their SPO2 levels were lower, in some cases dangerously lower than the actual reading.4-7 These grossly decompensated patients in many instances had a prolonged clinical course of care—and tragically a portion died.

Skin signs are another important assessment parameter in diagnosis. Warm and dry point more to a stable patient. Pale, cool, moist point to severe distress. Cyanotic skin means your patient is grossly deoxygenated and is in critical condition.2 Evaluation of cyanosis in patients who have darker skin color may be easier to see around the nailbeds or in the mucous membranes, the lips, gums, and around the eyes. When you pull down a patient’s lower eyelid, look at the palpebral conjunctiva, the inner surface of the lower eyelid.1-2

Mental Status

What is the patient’s mentation? This is a key indicator of perfusion and oxygenation of the brain. Even if a patient can’t speak, if they are alert and able to follow commands this is better than a patient who is fatigued or who has a decreasing level of consciousness. If you find a patient slumped over, breathing slowly, with decreased level of consciousness, you should get ready to intubate and you should be prepared to perform CPR.

Heart Rate and Respiratory Rate

A rapid pulse rate points to compensatory mechanisms to maintain adequate oxygenation. How does the patient respond to treatment? Did their heart rate go down or stay the same? Is the patient having PVC’s or other aberrant rhythms because they are so starved for oxygen their heart is incredibly irritable? How do these changes reflect the administration of medication, for example albuterol, which will increase your patient’s heart rate?

Wherever heart rate goes, respiratory rate will follow. Respirations increase to meet the metabolic oxygen demands of the body. Respiratory rates that are too fast, more than 28, 29, 30 breaths per minute, mean we need to track a patient’s breathing and assist his or her respirations. When respirations are too fast and shallow, gas exchange cannot take place. Patients cannot deliver oxygen to the vital organs, and they retain CO2, becoming acidotic.

Intersperse a breath every six seconds where we give the patient a full breath.  It may be difficult to seal a BVM to the patient’s face while giving a forceful breath. Consider CPAP if the patient doesn’t have an altered mental status or is unconscious. If you have a patient who is severely hypercapnic, endotracheal intubation may be the only solution. On the other hand, if your patient is breathing too slow, you need to breathe for them and bring their respirations up to 10 to 12 breaths per minute.

Respirations that are too slow may point to patient fatigue, but if you have an asthma patient, who is wheezing or is not wheezing, and they have a decreased level of consciousness, and they are bradycardic, with slow respirations, this is an ominous sign. You should not be surprised if the patient goes into cardiac arrest. You need to intervene rapidly. Be aggressive.

Phonation/Positioning/Accessory Muscles/Lung Sounds

Ability to speak (phonation) is another assessment tool. Ask the patient to count to 10 on one breath. If the patient can count from one to 10 without stopping to take a breath, they may be in mild distress, but they are not in severe distress. If they can only speak a one- or two-word sentence or they can’t speak at all, you have someone in severe distress.

Positioning is a huge clue. If your patient is sitting and able to answer questions without difficulty, they may be in mild to moderate distress. You may find patients standing upright or sitting in a tripod shape—placing their hands on their knees and bracing forward, trying to optimize their body position to improve maximal respirations. These patients are in severe distress. You may have patients who are in such severe distress that they will pull off a high-flow oxygen mask because they are hypoxic. These patients are not exhibiting an attitude issue; this may be a warning sign that they’ll proceed into respiratory or cardiac arrest. The most serious patient you will encounter is one who is slumped over or worse, who is lying flat because they are in this pre-cardiac arrest syndrome.

Note the use of the patient’s accessory muscles. This is a serious issue for a few different reasons. First, accessory muscle use by patients is meant to optimize inhalation. Patients will attempt to enhance their inhalation by retracting their intercostal muscles, using the sternocleidomastoid muscles to lift their clavicles, and having their diaphragm contract downward. This allows the patient to get the maximum amount of air that they can. Sometimes these changes are subtle, and sometimes they are very pronounced. Increased accessory muscle use further increases metabolic oxygen demand, exacerbating the patient’s asthma attack.

All that wheezes is not asthma. It could be anaphylaxis, cardiac asthma (a precursor to congestive heart failure), or COPD. Wheezing during an asthma attack is generally heard during expiration but may extend into inspiration as well. The most foreboding presentation is a silent chest, where no matter how deeply a patient tries to draw air in, their airways are so constricted you can’t hear any movement at all.

History

The patient’s past medical history will be revealing. Have they been intubated in the past? Have they ever been admitted to the ICU? It may provide clues as to the anticipated progression and potential severity of the patient.

Ask a patient how long they have been in distress; some asthma patients will exhaust every measure possible to avoid the emergency department. They may experience increasing distress for hours or days before they call 9-1-1. They may also be dehydrated from their increased respiratory rate and their medications like bronchodilators and corticosteroids, which can have a diuretic effect. The effort of breathing during an attack, especially in severe cases, can be physically exhausting, requiring more energy and fluid use by the body.

Patient Presentation

Every human being is different, and a patient’s presentation may be different from encounter to encounter. We may come across individuals who are in what we consider mild distress because of their vital signs, presentation, etc., but they’re complaining of being in severe distress. We may meet patients who are in severe distress, but when asked to rate their distress they give it a low number indicating it’s mild to moderate. Respiratory distress has elements of being a subjective phenomenon, one that is based on perception. If your patient is complaining of severe distress, be diligent and make sure you meet their needs.

Re-Assessment

Just as assessment points the way to patient severity, re-assessment of the patient after we begin treatment is crucial. How did the patient make out after we administered oxygen and nebulized medications and treated with steroids, CPAP, and ETI? Are they getting better or worse? If our patient isn’t experiencing any relief, what other tool, technique, or medication do we need to implement?

Conclusion

Effective assessment of asthma in EMS hinges on keen observation, comprehensive understanding, and prompt intervention. EMS professionals must be adept at interpreting both the obvious and subtle signs of respiratory distress, understanding the limitations of diagnostic tools like pulse oximeters, and appreciating the nuances of patient presentation that vary with individual characteristics, including skin pigmentation and history. The importance of continual re-assessment can’t be overstated. Each patient encounter is unique, and what may appear as mild distress could be a harbinger of a more serious condition.

The ability to discern the severity of an asthma attack and act swiftly could mean the difference between life and death. We must remember that asthma, while often manageable, can rapidly escalate to a life-threatening emergency. Our readiness to adapt our treatment strategies based on ongoing assessment and re-assessment is critical. This includes being prepared for rapid deterioration, understanding the implications of a patient's past medical history, and acknowledging the subjective nature of respiratory distress.

References

1. AMLS: Advanced Medical Life Support: Advanced Medical Life Support 3rd Edition by National Association of Emergency Medical Technicians (NAEMT), Jones and Bartlett, 2021
2. “The Paramedic,” McGraw-Hill, NY, NY April 2011
3. Bickler PE, Feiner JR, Severinghaus JW. Effects of skin pigmentation on pulse oximeter accuracy at low saturation. Anesthesiology. 2005 Apr;102(4):715-9. doi: 10.1097/00000542-200504000-00004. PMID: 15791098.
4. Gudelunas MK, Lipnick M, Hendrickson C, Vanderburg S, Okunlola B, Auchus I, Feiner JR, Bickler PE. Low Perfusion and Missed Diagnosis of Hypoxemia by Pulse Oximetry in Darkly Pigmented Skin: A Prospective Study. Anesth Analg. 2024 Mar 1;138(3):552-561. doi: 10.1213/ANE.0000000000006755. Epub 2023 Dec 18. PMID: 38109495.
5. Sylvia E K Sudat, Paul Wesson, Kim F Rhoads, Stephanie Brown, Noha Aboelata, Alice R Pressman, Aravind Mani, Kristen M J Azar, Racial Disparities in Pulse Oximeter Device Inaccuracy and Estimated Clinical Impact on COVID-19 Treatment Course. American Journal of Epidemiology, Volume 192, Issue 5, May 2023, Pages 703–713, https://doi.org/10.1093/aje/kwac164
6. Jamali H, Castillo LT, Morgan CC, Coult J, Muhammad JL, Osobamiro OO, Parsons EC, Adamson R. “Racial Disparity in Oxygen Saturation Measurements by Pulse Oximetry: Evidence and Implications.” Ann Am Thorac Soc. 2022 Dec;19(12):1951-1964. doi: 10.1513/AnnalsATS.202203-270CME. PMID: 36166259.
7. Shi C, et al. “The accuracy of pulse oximetry in measuring oxygen saturation by levels of skin pigmentation: a systematic review and meta-analysis.” BMC Med. 2022 Aug 16;20(1):267. doi: 10.1186/s12916-022-02452-8. PMID: 35971142; PMCID: PMC9377806.