Influence of patent ductus arteriosus and ventilators on electrical velocimetry for measuring cardiac output in very-low/low birth weight infants

Objective:we evaluated electrical velocimetry, a noninvasive method for continuous cardiac output measurement, in very-low and low birth weight infants and the influence of patent ductus arteriosus (pda) and ventilators on this method.study design:this prospective study compared 81 pairs of simultaneous cardiac output measurements by electrical velocimetry and transthoracic echocardiography in 28 patients. data were compared by correlation, bland–altman analysis and two-way analysis of variance.results:the two methods exhibited a high correlation (r=0.859, p<0.0001). the bias (mean difference of the methods) and percent error (100 × 1.96 × s.d./mean cardiac output) were −6 ml min−1 and 29.2%, respectively. pda significantly affected the bias (p=0.0004), but ventilators did not (p=0.14). hemodynamically significant pda had a larger bias (−36 ml min−1) and higher percent error (38.6%).conclusions:although influenced by pda, electrical velocimetry was generally interchangeable with transthoracic echocardiography even using ventilators.