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To determine the usefulness of the noninvasive pulsed Doppler in critically ill children, we calculated cardiac output by using this technique and compared the results with values obtained by the thermodilution method. Ten critically ill children who required invasive hemodynamic monitoring with a flow-directed Swan Ganz catheter were selected for this study. The subclavian vein was catheterized in all patients and a #5 Swan Ganz catheter was introduced in 5 patients (ages 8 to 16 years). Fifty-two cardiac output determinations were performed with a Gould SP 1435, 115 VAC, 50-60 Hz thermodilution computer. Simultaneously, patients' ascending aortic blood flows were determined using a Cardioflo (R) pulsed Doppler cardiac output computer (105-125V, 60 Hz by Cardionics, Inc.). A pediatric 3.5 MHz transducer, 6mm diameter, with bidirectional nonfocused capabilities was utilized via a transcutaneous suprasternal approach. After determining Doppler probe position and penetration depth, maximum velocity signals were obtained and a Hewlett Packard adapted flouroscope was used to determine adequacy of ascending aortic wave forms. The diameter of the aorta was measured by m-mode echocardiography and dialed into the computer, which calculated crosssectional diameter of the aorta (A = πd2 T 4cm2). Ascending aortic blood flow (cardiac output) was then derived by using the formula, FLOW = VELOCITY × CROSS-SECTIONAL DIAMETER. Thermodilution cardiac output values were compared with aortic flow calculated from Doppler signals. Linear regression analysis of cardiac output measurements showed to correlate significantly. Linear regression = 0.98, Y intercept = 0.98105X + 0.0687, with a range of 1,620-7,610 ml/min. We conclude that pulsed Doppler determination of cardiac output is a reliable, effective and safe noninvasive method to measure cardiac output in critically ill children.

Thirty-six hearts of patients who died with indwelling Swan-Ganz catheters in place were prospectively examined to assess the incidence and extent of localized lesions in the right side of the heart. Bland mural thrombosis in the superior vena cava, the right atrium and the pulmonary artery was found in 22 of 36 cases (61%). Patients with catheter periods greater than 2 days had a greater incidence and extent of bland mural thrombosis (79%) than patients with short-term catheterization (41%, p less than 0.01). Anticoagulation had no influence on bland mural thrombosis. Valvular hemorrhage occurred in 31% and aseptic valvular vegetations in 8% of the hearts. No case of infective endocarditis was found. Four of 36 cases (11%) had evidence of pulmonary infarction that appeared to be unrelated to the lesions in the right side of the heart. Endocardial lesions were common complications of indwelling Swan-Ganz catheters but had no significant impact on the clinical courses of the patients.