Dyspnea, the subjective experience of difficult breathing, is a common complaint in the ED and prehospital setting. As a presenting complaint it comes with a wide differential, ranging from benign causes to life threatening ones. It is the goal of the EMS provider to look for and rule out life threats first, and then formulate a working diagnosis that fits the patient's presentation and history. There are 3 potential causes we need to consider when approaching a patient who is “short of breath”:
Cardiovascular causes.
Pulmonary causes.
Metabolic causes (acidosis, or infections).
In general, the lethal differential to work through includes:
-Acute Cardiogenic Pulmonary Edema
-COPD exacerbation
-Myocardial infarction
-Pulmonary Embolism
-Metabolic acidosis
-Infection (Pneumonia or sepsis)
Other causes exist that may present acutely, such as an asthma attack, or anaphylaxis. However, these conditions are usually known to the patient and don't typically require much digging into history to identify.
Assessment of the patient with dyspnea:
Primary assessment includes an assessment of the patient's work of breathing. So, before we even get to history taking we need to determine the presence, and severity, of respiratory distress. Our main priority is to address the patient's respiratory distress before it progresses to respiratory failure. My general approach is to look for obvious accessory muscle use, pallor, cyanosis, and “head bobbing”, or tripod positioning as I approach the patient. As I assess the pulse I slide the pulse oximeter onto the patient's index finger. Bear in mind that several conditions can lead to poor perfusion, and the oximeter may not be reliable; treat the patient not the monitor. During the primary assessment, if the patient is noted to be in moderate respiratory distress, apply supplemental oxygen. If respiratory distress is severe, PPV with a BVM may be necessary. In general mild respiratory difficulty, in a patient who can speak full sentences, does not require urgent intervention. Once the ABCs are taken care of, have your partner get vitals, while you get a history of the presenting illness, and perform your secondary assessment. In this case we want to know:
-What are the patient's symptoms? We know they are short of breath, so assess for associated chest pain, dizziness or weakness, nausea, cough, and fever.
-Does the patient have a history of respiratory problems? This may be evident if the patient is on home O2, but it may not always be so clear. If the patient does have breathing problems, what are those problems?
-Is the patient on puffers? Have they taken them and did it help?
-When did the shortness of breath begin? Did it start suddenly, or did it develop over a period of time?
-If it started suddenly, what was the patient doing when it began? Was the patient jogging, gardening, lifting heavy boxes, or were they sitting on the cough doing nothing? We want to see if exertion is a provoking factor?
-Has the patient travelled recently, been hospitalized, or had any surgeries in the past month? This is important because it allows us to look for 2 possible causes: Infection, and potentially DVT.
-What is the patient's medical history?
-What medications is the patient currently taking?
-Does the patient have any known allergies.
Physical assessment should be performed concurrently with the history. This begins with auscultation of the posterior chest, looking for any adventitious sounds. We also want to assess chest wall movement for symmetry, and AP diameter. There is benefit to listening to heart sounds at this point if you are considering cardiac causes. Doing so in a loud ambulance is usually futile. Also, assess distal extremities for edema or cyanosis.
Working through the differential:
Starting with auscultation, we should be able to appreciate obvious adventitious sounds. Wheezes indicate bronchoconstriction, which is consistent with COPD/Asthma exacerbation, but also may be an early sign of pulmonary edema. If the patient has a history suggestive of CHF, assess the feet and ankles for edema. If the patient is hypertensive (usually quite high with a SBP >180mmHg), there is a good chance that you have cardiogenic pulmonary edema. If you hear diffuse course crackles (rales) you may also want to consider this diagnosis. If, however, you only appreciate wheezes, and the patient lacks additional indications of CHF, and has a history of COPD, especially if they have had a recent infection, you would most likely be dealing with a COPD exacerbation. If the patient has associated chest pain, we want to perform an OPQRST assessment to determine if the pain began at the same time as the shortness of breath, if it is localized or diffuse, and if it is pleuritic or not. Localized, pleuritic chest pain should raise concerns about pulmonary embolism. In this case we want to consider the patient's answers to questions about travel, surgery, or hospitalizations. We also want to ask about other risk factors such as hormone use, smoking, or cancer. In general, most of these patients will also have a DVT, or history of DVT. If, on the other hand, the patient's pain is sharp, pleuritic, and diffuse, with recent fever/chills, and a cough, pneumonia should be considered. Auscultation over the affected lung tissue should reveal rhonchi, and possibly hyper-resonant breath sounds. If the patient has pain that is non-pleuritic, we should be considering myocardial infarction as a possibility. This is especially true if the patient is diaphoretic, or complains of nausea (both are actually more sensitive findings for MI than chest pain alone). If the patient has an elevated respiratory rate, with deep inhalation, and a history of diabetes, we should be considering DKA as a potential cause. Although acidosis is not truly a respiratory problem, it often gets called in as one.
All patients who present with dyspnea without a known etiology (ie: a history of COPD), should receive a 12-lead ECG. 1/3 of MI do not present with chest pain, although its presence should be a red flag.
REMEMBER YOUR VITAL SIGNS:
Although it is obvious that we need to keep an eye on SPO2, the other vitals matter too. Using ETCO2 is valuable because it helps to determine if the problem is a ventilation one or a perfusion one. Elevated ETCO2 indicates CO2 retention, consistent with obstructive lung disease, and will present a characteristic “shark fin” waveform in the presence of bronchoconstriction. In contrast a condition such as PE will often present with a very low ETCO2 despite apparently adequate respirations. This is because the lung tissues are not being properly perfused. Hyperventilation in conditions such as DKA will also demonstrate a low ETCO2, however PE usually has a much lower readout (<24mmHg). As mentioned above, BP is important in looking at potential ACPE, and MI. It is worth noting that the most common cause of ACPE is left sided MI, which is why we do a 12 lead. Heart rate, and ECG provide a lot of information about the cause of our patient's dyspnea too. Various tachydysrhythmias and bradydysrhythmias will cause dyspnea. Sinus tachycardia may also be present as a compensatory mechanism in left ventricular failure, secondary to MI, in the setting of PE, or in the septic patient.
In general a full set of vitals, combined with the patient history is useful in ruling in/out variables in the differential.
Presentations for different causes of Dyspnea:
ACPE:
-Rales, or wheezes auscultated diffusely
-Lower extremity edema
-Tachycardia, and HTN
-Potentially a wet productive cough of frothy sputum (maybe pink tinged)
-Worsened by lying flat, and the patient may have woken from sleep short of breath. May sleep with several pillows.
-Usually a cardiac history (MI, CAD, HTN, DM)
-May report recent weight gain.
COPD:
-Usually the patient has a known history
-Often on home O2
-May have chronic cough (bronchitis), and usually have SPO2 88-92%
-Exacerbation is typically brought on by recent infection, abnormal amount of exercise, or a hot dry environment.
MI and PE: Both were covered in the chest pain post, so it seems silly to repeat myself here.
DKA:
-History of type 1 DM
-Non-compliance with insulin use, or a recent infection.
-Altered LOA
-Kussmaul's respirations
-Abdominal pain or nausea
-Warm dry skin.
-High BGL
Pneumonia:
-Sharp, diffuse, pleuritic chest pain
-Cough (may or may not be productive
-Rhonchi and crackles on auscultation of the affected region.
-May be febrile.
-May have signs of SIRS
As you can see, there are a variety of causes that present similarly. A good history is your friend here. It gives us many clues as to potential causes for the patient's condition. The physical assessment, review of vitals, and the 12-lead allow us to narrow and confirm our diagnosis. It is important to not that WE MAY STILL BE WRONG. Thats okay, as long as you have used sound judgement and a good clinical process to reach your conclusions. Dyspnea is a very non-specific symptom, and a hard one to fully diagnose in the prehospital environment. Ultimately, imaging, ultrasound, ABGs, and various other tests can be performed in the hospital once we get there. The goal of our assessment is to allow us to choose a treatment path that we feel will benefit our patient, and help them until we can get to definitive care.
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