TRANSTRACHEAL DOPPLER IN INFANTS AND SMALL CHILDREN FOLLOWING SURGERYFOR CONGENITAL HEART-DISEASE - RATIONAL USE OF AN IMPROVED TECHNOLOGY

Objective: To compare measurements of cardiac output utilizing an impr oved transtracheal Doppler technology with measurements obtained using two-dimensional echocardiography. Design: Prospective, descriptive st udy. Setting: Cardiovascular intensive care unit at a university medic al center. Patients: Fourteen children ranging in age from 14 days to 3 yrs (mean 1.3 +/- .97 yrs) following surgery for complex congenital heart disease. Interventions: Simultaneous cardiac output determinatio ns using transtracheal Doppler and two-dimensional echocardiography we re compared. Cardiac output was determined using measurement of blood velocity and diameter of the ascending aorta following surgery. Direct aortic diameter measurements made at operation were compared with mea surements obtained by transtracheal Doppler, two-dimensional echocardi ography and angiography. Results: The mean difference in aortic root d iameter between measurements made directly at operation and transtrach eal Doppler was 5%, compared with 13% by two-dimensional echocardiogra phy, and 21% by angiography, a significant difference by analysis of v ariance (F[3,31],p < .007). Post hoc comparisons demonstrated signific ant (p < .05) differences between echocardiography and angiographic ao rtic diameters. The mean difference between transtracheal Doppler and echocardiographic determination of cardiac output was 10.9% (t[10] = - 1.37, p = .007). Conclusions: An improved transtracheal Doppler techno logy compares favorably with echocardiographic determination of cardia c output in infants and young children. This improved technology may p rovide a useful means to assess cardiac output and may allow titration of therapy in critically ill infants and children.