Pulmonary Embolism Diagnostic Tool (PEDT)

The Pulmonary Embolism Diagnostic Tool (PEDT) is a clinical decision support tool designed to help healthcare providers assess the likelihood of a pulmonary embolism (PE) in patients presenting with symptoms such as shortness of breath, chest pain, cough, or hemoptysis. A pulmonary embolism is a potentially life-threatening condition that occurs when a blood clot (usually from the deep veins of the legs or pelvis) travels to the lungs and obstructs a pulmonary artery, causing a reduction in blood flow and oxygenation. Early detection and appropriate management of PE are crucial to prevent complications, including death.

What is Pulmonary Embolism?

Pulmonary embolism is a blockage in one of the pulmonary arteries in the lungs, most often caused by blood clots that travel to the lungs from the legs or other parts of the body (deep vein thrombosis, or DVT). It is a serious condition that can lead to significant morbidity and mortality if not diagnosed and treated promptly. Risk factors for PE include prolonged immobility, surgery, cancer, smoking, obesity, pregnancy, hormone therapy, and genetic predisposition to clotting disorders.

How the Pulmonary Embolism Diagnostic Tool (PEDT) Works

The Pulmonary Embolism Diagnostic Tool (PEDT) utilizes a combination of clinical criteria, patient history, and symptoms to estimate the pre-test probability of PE. The tool incorporates well-established clinical decision rules such as the Wells Criteria or Revised Geneva Score to stratify patients into low, intermediate, or high probability categories for PE. The tool also integrates other diagnostic information, such as D-dimer levels, a blood test used to measure fibrin degradation products that can indicate the presence of an abnormal blood clot.

Components of the PEDT

The PEDT incorporates various clinical criteria to assess the likelihood of PE. The most commonly used scoring systems within the tool include:

• Wells Criteria for Pulmonary Embolism: A widely used scoring system that assigns points based on clinical factors such as signs and symptoms of DVT, heart rate, recent surgery or immobilization, and alternative diagnoses being less likely than PE. Patients are classified as having low, moderate, or high probability of PE based on their total score.
• Revised Geneva Score: Another validated clinical decision rule that evaluates factors like age, heart rate, recent surgery, and hemoptysis, but without relying on subjective clinician judgment. It also categorizes patients into low, intermediate, or high risk.
• D-dimer Testing: The PEDT incorporates D-dimer testing as a rule-out test for patients with low or intermediate probability of PE. A negative D-dimer test can help exclude PE in these patients without the need for further imaging.

How to Use the PEDT

To use the Pulmonary Embolism Diagnostic Tool (PEDT), the healthcare provider enters the relevant patient information and clinical findings into the tool:

• Input basic patient data, including age, gender, and any known risk factors such as recent surgery, immobility, cancer, or previous history of DVT or PE.
• Evaluate clinical symptoms and signs, such as shortness of breath, pleuritic chest pain, leg swelling or tenderness, tachycardia (heart rate > 100 bpm), and hemoptysis (coughing up blood).
• Based on the Wells Criteria or Revised Geneva Score, assign points to each factor and calculate the total score to determine the pre-test probability of PE.
• Consider ordering a D-dimer test if the pre-test probability is low or intermediate. If the D-dimer test is negative, PE is unlikely, and no further testing may be needed.
• If the pre-test probability is high, or if the D-dimer is positive in low or intermediate-risk patients, further imaging is warranted, such as CT pulmonary angiography (CTPA) or ventilation-perfusion (V/Q) scan, to confirm or rule out PE.