Focused Cardiac Ultrasound by Nurses in Rural Vietnam

Abstract

Multiple studies investigating the use of focused cardiac ultrasound (FCU) in lower and middle-income countries and in medically underserved areas of the United States have demonstrated utility in echocardiographic screening algorithms performed by a variety of operators at different levels of training. No study to date has employed previously untrained nurses in a medically underserved setting to identify older adults with cardiac disorders. The aim of this study was to assess the accuracy of nurse-performed FCU to screen adult subjects at a village health center in Vietnam. Vietnamese nurses (N=8) underwent structured training conducted by sonographers and physicians during an outreach event sponsored by the American Society of Echocardiography Education and Research Foundation. The nurses were trained to detect abnormalities from a single echocardiographic view (parasternal long-axis) with a laptop-sized device and underwent pre- and posttraining testing. Following training, cardiac ultrasound examinations were performed on subjects >50years of age at a village health center. First, the nurses performed focused cardiac ultrasound using two-dimensional and color Doppler imaging in the parasternal long-axis view using the M7 device and recorded their assessments. Two-dimensional color and spectral Doppler echocardiography was thereafter performed using the same machine by a sonographer (n=5) or a Vietnamese echocardiography-trained cardiologist (n=1). Interviews and electrocardiography were performed at the time of FCU. Each nurse improved from pre- to posttraining (average improvement in correct answers, 21%; range, 2%-31%). During the scanning phase, nurses' sensitivity, specificity, and accuracy for identifying subjects with any abnormality were 51.5% (85 of 165), 78.1% (82 of 105) and 61.9%, respectively. There were 60 subjects with significant findings (22.2%); all of these subjects had significant abnormalities visible on parasternal long-axis images. Overall sensitivity, specificity, and accuracy for identifying subjects with major abnormalities were 83.3% (50 of 60), 78.1% (164 of 210), and 78.6%, respectively. Nurse-performed FCU demonstrated much higher sensitivity with lower specificity than electrocardiography alone. The combination of nurse-performed FCU plus ECG identified all of the significant findings on echocardiography and increased accuracy to 91.5%. Nurses with no prior echocardiographic experience and with limited training can identify patients with significant cardiac abnormalities using FCU with acceptable accuracy. Screening strategies involving FCU may play a role in improving access to health care and triage in underserved areas.