A pulmonary embolism is a blockage in the pulmonary artery caused by a blood clot in the lungs. This is a life-threatening condition and results in symptoms that respiratory therapists and medical professionals must be able to identify.
This case study will explore the events leading up to a patient being diagnosed with a pulmonary embolism, as well as the treatment and management of this condition.
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Pulmonary Embolism Clinical Scenario
You are called to the emergency room to treat a 25-year-old, 67 kg female patient. She is experiencing new onset chest pain and shortness of breath. She describes her chest pain as a stabbing sensation that radiates down to her left arm and gets worse during periods of exertion. She also feels lightheaded and highly anxious. In addition, the patient has a history of allergic asthma. Her only home medications are Microgestin Fe 1/20 (i.e., birth control) and albuterol PRN. She has no history of smoking or vaping.
- The patient’s pupils are round and reactive.
- She is mildly diaphoretic.
- She is showing signs of nasal flaring without pursed-lip breathing.
- Her trachea is located in the midline.
- She has no jugular venous distention.
- She has been coughing up small amounts of blood-tinged sputum.
- She has bilateral, decreased chest rise.
- Auscultation reveals crackles and a third heart sound.
- Palpation reveals normal tactile fremitus.
- Her percussion findings are normal at the apexes and decreased at the bases.
- She has a normal anterior-posterior chest diameter.
- Her chest is not tender to the touch.
- Her abdomen is soft and not distended.
- She shows no sign of digital clubbing.
- Her capillary refill time is 4 seconds.
- Her fingertips are slightly cyanotic and cool to the touch.
- She shows no signs of pedal edema.
- She has a moderately sized bruise on her right leg that is tender and warm to the touch.
- Respiratory rate: 30 breaths/min
- Heart rate: 120 beats/min
- Blood pressure: 100/75 mmHg
- SpO2: 85%
- Chest x-ray: Consolidation in both lung bases
Diagnosis and Treatment
Based on the patient’s assessment, history, and vital signs, what condition does the patient have, and why?
The patient is presenting with a pulmonary embolism (PE).
- The use of oral contraceptives is important for the diagnosis because one common side effect is hyper-coagulation.
- A bruise that is accompanied by tenderness and warmth in her leg is a sign of deep vein thrombosis (i.e., blood clot). This is important because blood clots can travel from the legs to the lungs, resulting in a pulmonary embolism.
- Other important signs include hypoxemia (i.e., low SpO2), increased capillary refill, cyanosis, and coolness to the touch. This could be caused by decreased perfusion and/or atelectasis.
- Diaphoresis and anxiety
- The patient has decreased percussion and crackles in the lung bases, which indicates atelectasis. Atelectasis can occur in patients who experience pulmonary infarction due to a pulmonary embolism.
- A third heart sound is sometimes heard in patients with a pulmonary embolism.
- Another important finding is the patient’s chest x-ray, which only shows atelectasis. A pulmonary embolism will not show up on a chest x-ray, but sometimes a wedge-shaped inflate will appear if pulmonary infarction has occurred as a result.
Bonus Point: You should have been able to recognize that, while the patient had a history of allergic asthma, their current presentation did not align with that of an asthma exacerbation. Remember that additional information may be given to you in scenario-based testing. When this happens, take note of the information in case it becomes important later on, but don’t let it distract you from the task at hand.
What tests can confirm the presence of a pulmonary embolism?
- Computed tomography pulmonary angiogram (CTPA): This is the preferred test for confirming a pulmonary embolism. The presence of a blood clot will show as a darkened area.
- V/Q scan: This is the second most preferred radiological test for a suspected pulmonary embolism. It will show a disturbance in gas distribution in the patient’s lungs when a thrombus is present.
- Pulmonary angiogram: This is the least preferred test because it is the most invasive. It involves the insertion of a catheter while dye is injected into the pulmonary artery, which will reveal the presence of an embolism.
You may also wish to recommend specific blood tests, such as D-dimer and platelet count. These will give you clues about the patient’s clotting status. D-dimer is most often used to look for the presence of a blood clot, as it will be increased if a clot is present.
It is important to remember that other factors can cause a patient’s d-dimer and clotting factors to increase; therefore, you should not rely on this test solely to confirm that a pulmonary embolism is present.
Let’s assume that you initiated the patient on oxygen therapy via nasal cannula at 2 L/min to try and correct their hypoxemia. After 20 minutes, you decided to incrementally increase the flow to 5 L/min, but there was no improvement in their oxygenation status.
Why is the patient’s SpO2 and PaO2 unresponsive to receiving supplemental oxygen?
This occurs because blood clots reduce or entirely prevent blood from flowing past a clot. Therefore, any alveoli distal to the clot will receive little to no perfusion. This decrease in perfusion prevents carbon dioxide and oxygen from effectively being exchanged at the alveolar-capillary membrane, even when the patient is ventilating normally.
This prevention of effective gas exchange due to low perfusion is part of what causes patients with a pulmonary embolism to be unresponsive to supplemental oxygen. The development of atelectasis due to pulmonary infarction secondary to a pulmonary embolism can further reduce the patient’s responsiveness to oxygen.
What other treatment methods would you recommend?
- Anticoagulants: The administration of a fast-acting anticoagulant, like heparin, and a slow-acting anticoagulant, like Warfarin should be recommended. This can help stop the existing clot from growing and to prevent new clots from forming. Patients who are prescribed Warfarin will need to have their other medications, dietary supplements, and nutrition plan reviewed. That is because medications, supplements, or food can impact the blood’s ability to clot while potentially negatively impacting the drug.
- Thrombolytic agents: The administration of thrombolytic drugs, such as altepase, streptokinase, or urokinase, can help break down the embolism. Patients who are prescribed a thrombolytic should be monitored for an increased risk of bleeding. This is especially true when prescribed heparin alongside a thrombolytic agent.
- Analgesics: These drugs can be administered for any pain the patient may be experiencing.
- Preventative actions: Ensuring the patient stays active, moves their limbs, is well-hydrated, and wears compression socks can help prevent another clot from forming.
- Pneumatic compression cuffs: These should be placed on the patient’s legs while they’re bedridden to decrease the risk of more blood clots forming.
- Surgical interventions: A pulmonary embolectomy can be performed to remove an existing clot that is not dissolved by medications. The placement of an inferior vena cava filter can also be used to prevent future clots from reaching the patient’s lungs. These filters are usually reserved for patients who are at high risk for developing further embolisms despite receiving pharmaceutical interventions.
A pulmonary embolism is a serious medical condition that can be difficult to diagnose. Respiratory therapists must be aware of the risk factors and symptoms to properly assess and treat their patients. A few key things to remember about patients with a pulmonary embolism include:
- They often present with radiating chest pain.
- They need radiological testing that is more extensive than a simple chest x-ray.
- They are often unresponsive to supplemental oxygen.
Treatment for a pulmonary embolism should be aimed at dissolving existing clots while preventing future clots from forming. Thanks for reading, and, as always, breathe easy, my friend.
John Landry, BS, RRT
John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.
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