title: A novel method of measuring cardiac output in infants following extracorporeal procedures: preliminary validation in a swine model.
abstract: In infants, technologies for obtaining rapid, quantified measurements of cardiac output (CO) following weaning from cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation are not readily available. A new technique to measure CO based on ultrasound velocity dilution is described. It utilizes reusable probes placed on the extracorporeal circuit that permits convenient measurement of CO prior to decannulation. This report provides preliminary validation data in an animal model. Three Yorkshire pigs (11-14 kg) were fully heparinized and cannulated via the right common carotid artery (cannula advanced to the aortic arch) and right atrium. Both the venous and arterial lines were instrumented with ultrasonic probes connected to a computer-monitoring system. A 'stopcock bridge' between the arterial and venous cannulas provided the access for saline injection and a controlled AV-shunt. For comparison, a vascular flow probe was fitted directly to the pulmonary artery (PA) in both animals and, for the larger animal, a PA catheter was inserted to obtain standard thermodilution measurements. Linear regression analysis revealed a correlation between the CO by ultrasound dilution (CO UD) technique and the vascular probe and PA thermodilution techniques to be R2 =0.94 and 0.81. This pilot study demonstrated that the CO UD technique correlates to other benchmarks of CO measurements. This novel technology has specific application in the field of pediatric open heart surgery in that it would allow the surgeon to accurately and inexpensively measure the CO of neonatal and pediatric patients before and after surgical manipulation of the heart without the need for placement of additional catheters or probes.
authors.affiliation: Department of Cardiovascular Perfusion, Department of Surgery, State University of New York Upstate Medical University, Syracuse, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Melchior
authors.forename: Edward
authors.initials: E
authors.lastname: Darling
authors.forename: Bryan
authors.initials: B
authors.lastname: Terry
authors.forename: Gordy
authors.initials: G
authors.lastname: Gunst
authors.forename: Bruce
authors.initials: B
authors.lastname: Searles
mesh_terms: D000818:Animals; D001011:Aorta; D001783:Blood Flow Velocity; D002302:Cardiac Output; D002315:Cardiopulmonary Bypass; D015199:Extracorporeal Membrane Oxygenation; D006801:Humans; D007223:Infant; D023421:Models, Animal; D011651:Pulmonary Artery; D015203:Reproducibility of Results; D034421:Sus scrofa; D013815:Thermodilution / Q000379:methods* / Q000592:standards; D014463:Ultrasonography / Q000379:methods* / Q000592:standards