Pulmonary Mean Transit Times in Normal Children and in Those with Heart Diseases with Left-to-Right Shunts

Early since the original application of indicator dilution methods to determine the circulation time by Hering in 1829 measurement of the total (systemic plus pulmonary) circulation time has become a common diagnostic procedure useful for recognition and assessment of heart failure. Nevertheless, informations concerning the more specific circulation time, the pulmonary mean transit time (PMTT), are still not adequate. Most of the past studies on PMTT were limited to experimental animals and adults. To the best of our knowledge, no data on PMTT in he heart diseases with left- to-right shunts have ever been published in the literature. The present study was designed to determine PMTT in normal children and in those with atrial septal defect, ventricular septal defect, patent ductus arteriosus or other congenital heart diseases with left-to-right shunts utilizing a new indicator dilution technique10. The relation of PMTT to the body weight, body height, body surface area and other hemodynamic factors were evaluated by means of regression analysis. Discussions on some special problems involved in the determination of the circulation time in infants and children were also made.