Chest pain is probably the number one reason people go to the ED, and it makes up a significant number of 911 calls. Although the chief complaint of chest pain raises red flags for most of us, the majority of the time the pain is actually due to non-life-threatening causes. According to Harrison's Principles of internal medicine, ischemia accounts for only 31% of chest pain patients seen in the ED. Gastrointestinal causes, and chest wall syndromes make up a hefty majority of the discharge diagnosis for patients with the complaint of chest pain. Physicians use a number of criteria to diagnose ischemic vs non-ischemic causes, including patient history, ECG findings, patient age, cardiovascular risk factors, and serum troponin levels are used to risk stratify these patients. Additional tests such as CT angiography allow for further narrowing a diagnosis.
BUT... we don't have most of the definitive tests available in the field. So where does this leave us in the prehospital environment? Well, it leaves us in a position where missing critical features can prove catastrophic for our patients. How do we overcome this? By taking a thorough patient history, assessing for risk factors, and performing a critical physical assessment including 12-lead ECG interpretation.
The standard approach:
All patients presenting with chest pain should be assessed in the same standard way. By following a routine assessment we reduce the risk of making judgement errors and misdiagnosing them. An NOPQRST-ASPN format allows us to get a thorough history of the pain.
N- Is this pain NEW, or has the patient experienced it before? Was there ever a diagnosis made?
O- What was the onset of the pain? Was it sudden or did it develop gradually over hours or days?
P- What PROVOKES the pain? What was the patient doing when the pain started? Has anything improved the pain (positioning, medications, etc).
Q- What is the QUALITY of the pain? Is it sharp, dull, heavy, squeezing. Is it localized or diffuse?
R- Does the pain RADIATE to another area?
S- What is the SEVERITY of the pain. Is it more severe now than when it started?
T- Time. Is the pain constant or does it come and go?
ASPN- Associated symptoms/Pertinent negatives. Is the patient short of breath? Are they nauseated? Have they had a recent cough, and is it productive? Any recent fever or chills? Has the patient travelled recently? Any hospitalizations or surgeries in the past month? Has the patient had any recent medication changes?
This allows us to start working out what the causes may be. In general, we always want to treat for the worst possible cause. The differential of consequence for chest pain includes:
-Aortic dissection
-Myocardial infarction
-Dysrhythmia
-Pulmonary embolism
-Pneumothorax
-Pneumonia
There are other causes, but these are the ones that will kill patients if missed emergently. Our assessment lets us work through them to rule-in/rule-out potential causes of the pain. Conditions that present with sudden onset include: Aortic dissection, MI, Dysrhythmia, PE, and pneumothorax. A gradual onset would lead us toward potential causes such as pneumonia. Pain that is brought on by exertion, and alleviated by rest leads us down a cardiac pathway, whereas pain that is unrelated to exertion, may still be cardiac, but also may relate to other pathologies. The quality of the pain says a lot. Pain that is sharp, pleuritic, and well localized speaks to PE and pneumothorax, whereas sharp, diffuse, pleuritic pain is characteristic of pneumonia. Dull, heavy, or squeezing pain is common in MI, and the patient may hold a closed fist over the sternum (Levigne's Sign) when describing the pain. Sharp, “Tearing” pain is often related to aortic dissection. Radiation to other areas is characteristic of MI, but also present in aortic dissection (felt between the shoulder blades), whereas a PE will be localized to a small area of the chest. Pneumothorax may present with non-radiating pain on only one side of the chest, and pneumonia will be a diffuse pain. Severity varies as pain is a subjective feeling. Pain scale alone should not be used to diagnose. Whether or not the pain is constant or intermittent is important though. MI usually presents with constant pain that may gradually increase over time, while an aortic dissection will reach maximal intensity in seconds and will stay that way. PE, pneumothorax, and pneumonia will all fluctuate with movement and respiration.
You'll notice I haven't discussed dysrhythmia yet. That is because we can assess for this based on 2 things: 1) The description of the pain, and 2) the ECG tracing. Dysrhythmias that are symptomatic usually are very apparent once your leads are placed.
Here are common features of the conditions discussed above:
Aortic dissection:
-Sharp “tearing” chest pain that radiates to the mid scapula
-Reaches maximal intensity at onset
-Possible bilateral BP differences
-Possible pulse deficit on one side
-If the dissection tears anterograde there may be signs of a stroke
-If the dissection tears retrograde, there may be a tamponade, and potential presence of electrical alternans on the ecg.
-Beck's Triad may also occur.
Myocardial infarction:
-Heavy, “squeezing”, or “crushing”, chest pain that may radiate to the arm, neck, or jaw.
-Dyspnea
-Nausea
-Pallor
-Diaphoresis
-Hypertension or hypotension
-Tachycardia or bradycardia
-A history of cardiovascular risk factors (Prior MI, angina, CAD, HTN, DM, Smoking, Obesity)
-Potential 12-lead ECG findings
Dysrhythmia:
-Palpitations
-Dizzyness/weakness
-Pallor
-Syncope/Pre-syncope with possible recent episodes of the same
-Dyspnea
Pulmonary Embolism:
-Sharp “Pinpoint” Pleuritic chest pain
-Dyspnea
-Low SPO2 despite supplemental O2
-Low ETCO2
-Hypotension in massive PE
-Tachycardia
-Hypercoaguable state (Cancer, Hormone use, Smoker, sedentary, recent surgery, recent long distance travel, history of blood clots).
-Presence of or history suggestive of a DVT
Pneumothorax:
-Sudden, sharp, unilateral chest pain
-Dyspnea
-Low SPO2
-JVD if severe
-Diminished or absent breath sounds on the affected side
-History of obstructive airway disease, smoking, or trauma.
-May occur without cause; often in young tall males.
Pneumonia:
-Gradual onset of sharp, diffuse, chest pain
-Fever or chills
-Productive cough
-Rhonchi on auscultation, or hyper-resonant lung sounds over affected area of consolidation (often the right lower lobe).
-Elevated resp rate
-Diminished SPO2
-Diminished ETCO2
-Possible signs of SIRS/SEPSIS
Why diagnosis matters:
Despite the fact that all of these conditions present in a similar manner, they are all treated quite differently. It is important to avoid misdiagnosis as some treatments can worsen certain conditions. For example: Giving nitroglycerine to a patient with a PE can be a fatal error, as it will drop the preload to the right ventricle, and eliminate its ability to overcome the pulmonary hypertension caused by the embolus. ASA should NOT be given in the case of aortic dissection, as this will lead to worsening of a hemorrhagic state. These are just a few examples of why we need to have a clear idea of what is going on with our patient prior to initiating treatment. When forming a diagnosis, we ultimately want to consider the critical possibilities, and then use our assessments to narrow things down to 3 categories:
Most likely diagnosis
Most lethal if missed
Less likely diagnoses
Here is an example case:
At 0430 on a Sunday morning, you are called code 4 for a 68 year old male complaining of sudden onset chest pain approximately 30 minutes earlier. On arrival you enter the residence to find the patient seated on the toilet in the upstairs washroom. From the doorway, you note him to be overweight, leaning forward with his elbows resting on his knees and his face in his hands. After introducing yourself you determine the patient to be alert, speaking full sentences, with a weak, rapid radial pulse. He is pale, and sweating profusely despite the temperature being quite comfortable in the home. The patient reports that his bedroom is on the first floor and at 0400 he had to climb approximately 12 steps to get upstairs so he could use the washroom. He states that he was feeling slightly short of breath when he awoke, and that by the time he had reached the 6th step he had to stop to catch his breath. Since reaching the washroom, the patient has had pain in the centre of his chest that hes describes as “Just tight, you know? Like someone is squeezing a belt around my chest”. He states that resting has not relieved his discomfort, and that he also has an ache in the left side of his jaw that developed since calling 911. He rates his pain at an 8/10 and states that it is getting worse. He says the pain is constant, and it does not change when you ask him to take a deep breath. He denies any nausea, fever or chills, and states that he has not travelled, had any hospitalizations or surgeries in the past month, and that he has no med changes. The patient has a history of NIDDM, HTN, and takes tylenol for chronic back pain. The vitals obtained by your partner are:
Pulse: 120, 3 lead shows sinus tachycardia
Respirations: 22, and shallow
Temperature: 36.8 degrees celsius
BP: 190/100
SPO2 97% on room air
Auscultation reveals clear lungs bilaterally.
Meds: Metformin, Metoprolol, Tylenol
Allergies: NKA
Here we have a patient who presents with exertional chest pain, described as tight and squeezing, with associated dyspnea, pallor, and diaphoresis. The pain had a sudden onset, and is getting worse. Right off the top, we can move aortic dissection to the “less likely” category. The quality of the pain and the fact that it is not pleuritic, or associated with chills/fever, cough, or unilateral breath sounds, allows us to eliminate PE, pneumothorax, and pneumonia. Absence of abnormal ecg findings allows us to eliminate dysrhythmia. This leaves us with MI as our most likely culprit.
A 12-lead ECG is performed and presents with sinus tachycardia, and 3mm elevation in V1, as well as 2mm elevation in V4.
This allows us to confirm a diagnosis of STEMI as the cause of the chest pain.
As stated at the beginning of this post; chest pain is very common, and not all causes are life threatening. That being said, it is not our job to look for benign causes. We need to assume life threatening illness is present, and then begin to work out way back, eliminating potential threats until we reach a provisional diagnosis.
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