Accuracy in Manometry during Cardiac Catheterization in Children (Quantitative Assessment of Damping of the Systems of Manometry Using Various Catheters and Connectors)

Abstruct By using McDonald's pressure transient method, damping of the various systems of manometry at various frequencies was evaluated from the view point of amplitude and phase lag. Damping expressed by the natural frequency (ωo) of vibration of the system of pressure measurement and the relative damping (β) varied widely depending on the combinations of various catheters and connectors. Damping increased as the radius of the catheter decreased and by the attachment of the three way stop‐cock. In view of the fact that intracavitary pressure is composed of the sum of the first 5 to 6 harmonics of the fundamental frequency (heart rate), the degree of damping by two different catheter manometer systems was compared with each other (one with a 5F size NIH catheter, another with a 8F size NIH catheter) using the rectangular pressure contour as a reference input. Based on these results, importance was emphasized of giving sufficient consideration to the kind of catheter and type of connector used in cardiac catheterization of children.