Cardiopulmonary limited ultrasound examination for "quick-look" bedside application

Abstract

Although taking a "quick look" at the heart using a small ultrasound device is now feasible, a formal ultrasound imaging protocol to augment the bedside physical examination has not been developed. Therefore, we sought to evaluate the diagnostic accuracy and prognostic value of a cardiopulmonary limited ultrasound examination (CLUE) using 4 simplified diagnostic criteria that would screen for left ventricular dysfunction (LV), left atrial (LA) enlargement, inferior vena cava plethora (IVC+), and ultrasound lung comet-tail artifacts (ULC+) in patients referred for echocardiography. The CLUE was tested by interpretation of only the parasternal LV long-axis, subcostal IVC, and 2 lung apical views in each of 1,016 consecutive echocardiograms performed with apical lung imaging. For inpatients, univariate and multivariate logistic regression analyses were performed to assess the relations between mortality, CLUE findings, age, and gender. In this echocardiographic referral series, 78% (n = 792) were inpatient and 22% (n = 224) were outpatient. The CLUE criteria demonstrated a sensitivity, specificity, and accuracy for a LV ejection fraction of ≤40% of 69%, 91%, and 89% and for LA enlargement of 75%, 72%, and 73%, respectively. CLUE findings of LV dysfunction, LA enlargement, IVC+, and ULC+ were seen in 16%, 53%, 34%, and 28% of inpatients. The best multivariate logistic model contained 3 predictors of in-hospital mortality: ULC+, IVC+ and male gender, with adjusted odds ratios (95% confidence intervals) of 3.5 (1.4 to 8.8), 5.8 (2.1 to 16.4), and 2.3 (0.9 to 5.8), respectively. In conclusion, a CLUE consisting of 4 quick-look "signs" has reasonable diagnostic accuracy for bedside use and contains prognostic information.