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PA Catheter Interpretation — FRCA Final MCQ

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HardIntensive Care MedicinePA Catheter InterpretationFRCA Final

A 70-year-old man undergoes pulmonary artery catheterisation in the ICU. Correctly zeroed, end-expiratory measurements are: right atrial pressure 8 mmHg, right ventricular pressure 55/8 mmHg, pulmonary artery pressure 55/28 mmHg with a mean of 37 mmHg, pulmonary arterial wedge pressure 10 mmHg, and thermodilution cardiac output 4.0 L min−1. What is the most likely haemodynamic diagnosis?

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Correct answer: A — Pre-capillary pulmonary hypertension

The correct answer is A. The mean pulmonary artery pressure is elevated at 37 mmHg, the wedge pressure is normal at 10 mmHg, and the calculated pulmonary vascular resistance is 6.75 Wood units. This fulfils the haemodynamic definition of pre-capillary pulmonary hypertension: mean pulmonary artery pressure greater than 20 mmHg, wedge pressure 15 mmHg or less, and pulmonary vascular resistance greater than 2 Wood units. Left ventricular failure and mitral stenosis cause post-capillary pulmonary hypertension with an elevated wedge pressure. Tamponade typically produces elevated, near-equal diastolic filling pressures and reduced cardiac output. Hypovolaemia does not explain the markedly elevated pulmonary artery pressure and resistance. These measurements classify the haemodynamics but do not distinguish pulmonary arterial hypertension, lung disease-associated pulmonary hypertension, or chronic thromboembolic disease.

Reference: Humbert M et al. 2022 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension, haemodynamic definitions, 2022. https://pubmed.ncbi.nlm.nih.gov/36017548/