Diagnosis of Pulmonary embolism is confirmed by?

Appeared in: SCTIMST Staff Nurse - 2015 (Set-B)

Explanation

A positive D-dimer test is a highly sensitive screening tool for venous thromboembolism, including PE.
While not a confirmatory test itself, its primary role in the diagnostic algorithm is to identify patients who require definitive imaging.
A positive result, combined with clinical suspicion, triggers the use of confirmatory tests like CT Pulmonary Angiography (CTPA).
Among the given options, it is the most directly involved laboratory marker in the pathway to diagnosing PE.

Option A: Troponin T is a cardiac biomarker that becomes elevated due to myocardial injury. In PE, it indicates right ventricular microinfarction from acute pressure overload.
Option B: Pro-BNP (B-type Natriuretic Peptide) is released from the heart muscle in response to stretching, which occurs with right ventricular strain in a significant PE.
Option D: ECG findings in PE are highly variable, often non-specific, and frequently normal. The classic S1Q3T3 pattern (S wave in lead I, Q wave in lead III, inverted T wave in lead III) is seen in only a minority of cases.

Clinical Relevance

Nursing practice connection: Use the key finding related to Diagnostic workup for Pulmonary Embolism (PE) to guide bedside assessment, documentation, and the next nursing action.
The key takeaway is that no single blood test confirms PE; it's a clinical diagnosis supported by labs and confirmed by imaging.
A nurse's crucial role is preparing a patient for a CTPA, which includes assessing for contrast allergies (iodine, shellfish) and checking renal function (creatinine levels), as the contrast dye can be nephrotoxic.
Nurses must continuously monitor patients with suspected PE for signs of deterioration, such as worsening dyspnea, hypotension, or tachycardia, and be prepared for emergency intervention.

How to Approach the Question

First, identify the core of the question: it asks for a test that confirms the diagnosis of Pulmonary Embolism.
Recall or look up the 'gold standard' for PE diagnosis, which is CT Pulmonary Angiography (CTPA). Notice that this is not an option.
Evaluate the given options based on their role in the diagnostic process. Differentiate between screening tests, confirmatory tests, and prognostic markers.
Eliminate options that are primarily for prognosis (Troponin, pro-BNP) or are merely suggestive (ECG).
Select the remaining option (D-dimer) and recognize its role as a critical screening test that, when positive, leads directly to the confirmatory imaging step.
Conclude that in the absence of the true confirmatory test, the most integral diagnostic marker provided is the correct choice.

Concept Tested & Keywords

QrszFwZf9J2nKzHYxIsCkq

E6 Medicine Harrison 22e Part 2 p. 64-66

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 483-485

Practise the full SCTIMST Staff Nurse - 2015 (Set-B)

Attempt every question from this paper in a timed mock, then review the full solution for each one.