Pulmonary Embolism Case Study: Diagnosis and Treatment

A pulmonary embolism (PE) is a life-threatening condition that occurs when a blood clot blocks one or more arteries in the lungs, leading to impaired blood flow and oxygenation. The condition often develops suddenly and can cause severe complications if not diagnosed and treated promptly.

Risk factors for PE include prolonged immobility, surgery, and certain medical conditions that increase the likelihood of blood clot formation.

This case study examines the presentation, diagnosis, and treatment of a patient with a pulmonary embolism, highlighting the critical interventions required to manage this emergency.

Pulmonary Embolism Clinical Scenario

You are called to the emergency room to assess a 25-year-old female patient weighing 67 kg who presents with new onset chest pain and shortness of breath. She describes the chest pain as a stabbing sensation that radiates to her left arm and worsens during exertion. The patient also reports feeling lightheaded and extremely anxious. Her medical history includes allergic asthma, and her home medications include Microgestin Fe 1/20 (birth control) and albuterol PRN. She has no history of smoking or vaping.

Patient Assessment

HEENT

• Pupils are round and reactive
• Mildly diaphoretic
• Signs of nasal flaring without pursed-lip breathing
• Trachea is midline
• No jugular venous distention
• Reports coughing up small amounts of blood-tinged sputum

Chest and Abdomen

• Bilateral decreased chest rise
• Auscultation reveals crackles and a third heart sound
• Normal tactile fremitus on palpation
• Percussion findings are normal at the apexes and decreased at the lung bases
• Normal anterior-posterior chest diameter
• Chest is not tender to the touch
• Abdomen is soft and non-distended

Extremities

• No signs of digital clubbing
• Capillary refill time: 4 seconds
• Fingertips are slightly cyanotic and cool to the touch
• No pedal edema present
• A moderately sized bruise on her right leg that is tender and warm, raising concern for deep vein thrombosis (DVT)

Vital Signs

• Respiratory rate: 30 breaths/min (tachypnea)
• Heart rate: 120 beats/min (tachycardia)
• Blood pressure: 100/75 mmHg
• SpO2: 85% (hypoxemia)

Radiology

• Chest x-ray: Consolidation in both lung bases

Diagnosis and Treatment

This clinical presentation raises strong suspicion for a pulmonary embolism (PE), particularly with the combination of chest pain, shortness of breath, hypoxemia, and the tender bruise on the leg, suggestive of a possible DVT, a common source of PE.

Immediate diagnostic testing, such as a CT pulmonary angiogram, and prompt treatment are critical to manage this life-threatening condition.

Key Components Leading to the Diagnosis:

• Oral contraceptive use: The patient’s use of oral contraceptives is a significant risk factor, as these medications can increase the risk of hypercoagulation, leading to the formation of blood clots.\
• Signs of deep vein thrombosis (DVT): The bruise, tenderness, and warmth in her right leg strongly suggest DVT, which is a common precursor to PE. Blood clots in the leg can travel to the lungs, causing a pulmonary embolism.
• Hypoxemia and circulatory issues: The patient’s low SpO2 (85%), delayed capillary refill, cyanosis, and cool extremities indicate poor perfusion, likely caused by a blocked pulmonary artery reducing oxygen exchange and blood flow.
• Diaphoresis and anxiety: These are common signs of a pulmonary embolism, as patients often experience increased anxiety and sweating due to the sudden onset of chest pain and difficulty breathing.
• Hemoptysis: The presence of blood-tinged sputum (hemoptysis) is another indication of a pulmonary embolism, as the clot may damage blood vessels in the lungs.
• Atelectasis and lung sounds: The patient’s chest assessment revealed decreased breath sounds and crackles in the lung bases, indicating possible atelectasis (collapsed lung tissue). Atelectasis is a potential complication of pulmonary infarction, which can result from a PE.
• Third heart sound: The presence of a third heart sound may be heard in some patients with a PE, reflecting cardiac stress due to the embolism.
• Chest x-ray findings: While a chest x-ray typically does not show the presence of a pulmonary embolism, it did reveal atelectasis, which is consistent with pulmonary infarction. Occasionally, a wedge-shaped infiltrate may be seen if the embolism has caused infarction.

Diagnostic Tests to Confirm Pulmonary Embolism

• Computed tomography pulmonary angiogram (CTPA): This is the gold standard for confirming a pulmonary embolism. A blood clot will appear as a darkened area within the pulmonary arteries.
• Ventilation-perfusion (V/Q) scan: This test is an alternative to CTPA and measures air and blood flow in the lungs. A mismatch in ventilation and perfusion can indicate the presence of a thrombus obstructing blood flow.
• Pulmonary angiogram: Though rarely used due to its invasive nature, this test involves inserting a catheter and injecting dye into the pulmonary arteries to visualize an embolism.
• D-dimer test: A D-dimer blood test can help detect the presence of a blood clot, as elevated levels suggest clot formation. However, D-dimer can be elevated for other reasons, so it should not be relied upon as a definitive test for PE.
• Platelet count: Checking the platelet count can provide additional clues about the patient’s clotting status, although it is not the primary diagnostic tool for PE.

Note: While the patient has a history of allergic asthma, the clinical presentation in this scenario does not align with an asthma exacerbation. It’s essential to take note of all the patient’s background information, but stay focused on the current symptoms and findings that point to the most likely diagnosis—in this case, a pulmonary embolism.

Additional Treatment

Let’s assume the patient was started on oxygen therapy via nasal cannula at 2 L/min to address hypoxemia.

After 20 minutes, the oxygen flow was increased incrementally to 5 L/min, but there was no improvement in oxygenation.

Why is the Patient’s SpO2 and PaO2 Unresponsive to Supplemental Oxygen?

The lack of response to supplemental oxygen is due to the blood clot blocking or significantly reducing blood flow past the embolism. As a result, alveoli distal to the clot receive little to no perfusion, meaning that even though air is reaching the alveoli, blood is not available to pick up oxygen or remove carbon dioxide.

This impairs gas exchange at the alveolar-capillary membrane, rendering oxygen therapy ineffective.

This type of ventilation-perfusion mismatch is common in pulmonary embolism. Additionally, atelectasis can develop due to pulmonary infarction caused by the embolism, further reducing the patient’s responsiveness to supplemental oxygen.

What Other Treatment Methods Would You Recommend?

• Anticoagulants: Heparin (fast-acting) and Warfarin (slow-acting) are recommended to prevent the existing clot from growing and to reduce the risk of new clots forming. Patients on Warfarin require careful monitoring of their medications, supplements, and diet, as these can affect the body’s clotting ability and the effectiveness of the drug.
• Thrombolytic agents: Such as alteplase, streptokinase, or urokinase can be administered to actively break down the embolism. Patients on thrombolytics should be closely monitored for increased bleeding risk, especially if they are also receiving heparin.
• Analgesics: Pain management with analgesics is important for relieving discomfort caused by the embolism.
• Preventative actions: Encourage the patient to stay active, move their limbs, stay hydrated, and wear compression socks to reduce the risk of further clot formation.
• Pneumatic compression cuffs: Applying pneumatic compression cuffs to the legs while the patient is bedridden can help reduce the risk of developing additional clots.
• Surgical interventions: A pulmonary embolectomy can be performed to surgically remove a clot that does not respond to medication. An inferior vena cava (IVC) filter can be placed to catch clots before they reach the lungs. This option is reserved for patients at high risk of future embolisms who are not responding adequately to pharmaceutical interventions.

Note: These treatments aim to dissolve the clot, prevent further clot formation, and manage the complications associated with a pulmonary embolism, improving the patient’s prognosis.

Final Thoughts

Pulmonary embolism (PE) is a critical medical condition that can be challenging to diagnose due to its varied symptoms. For respiratory therapists, understanding the risk factors and recognizing the key symptoms are essential for accurate assessment and timely intervention.

A few important points to keep in mind when treating patients with PE include:
 

• Radiating chest pain is a common symptom.
• Extensive radiological testing, such as a CT pulmonary angiogram, is often required for diagnosis, as a chest x-ray alone is insufficient.
• Unresponsiveness to supplemental oxygen is typical, as the underlying issue is a blocked blood supply rather than a ventilation problem.

Note: Effective treatment focuses on dissolving existing clots and preventing future clots to reduce the risk of complications.