Abstract
<title>Abstract</title> <p> Point-of-care ultrasound (POCUS) is increasingly used in clinical practice, although its diagnostic utility for COPD remains unclear. In this prospective multicenter diagnostic accuracy study conducted between August 2023 and July 2024, adults referred for pulmonary function testing (PFT) at two tertiary centers underwent standardized lung and cardiac POCUS performed by blinded operators. Cardiac acoustic windows and anterior lung zones were graded for image quality using a structured 0–2 scale. COPD was defined according to GOLD spirometric criteria. Among 301 participants completing both POCUS and PFT, 80 (27%) met criteria for COPD. Lung ultrasound findings did not differentiate COPD from non-COPD. In contrast, poor parasternal views and high-quality subcostal views were independently associated with COPD (aRR 17.1, 95% CI 7.5–49.9; and aRR 2.64, 95% CI 1.17–7.67, respectively). A combined model incorporating POCUS findings, smoking history, and mMRC achieved an AUC of 0.94 compared with 0.84 without ultrasound. A derived Parasternal–Subcostal Score (0–4) demonstrated an AUC of 0.82, with a cutoff of 3 yielding a NPV of 92% and correlating with higher residual volume, total lung capacity, and greater use of COPD-related therapies. These findings suggest that specific cardiac POCUS patterns, particularly poor parasternal and preserved subcostal views, may serve as practical bedside indicators of COPD. <bold>Clinical Trial Registration</bold> NCT06251271. </p>