Micro-Prime Circuit Facilitating Minimal Blood Use during Infant Perfusion

Abstract

(J. Extra-Corpor. Technol. 19[3] p. 352-357 Fall 1987, 24 ref.) There is considerable concern about the use of blood products during cardiac surgery on the part of adult patients and the parents of pediatric patients. It has been fairly easy to eliminate blood usage in most adult patients but difficult to impossible in infants and small children. Most infant perfusion circuits require a priming volume of 500-850cc which may be cut to 400cc with substantial effort. These volumes are far in excess of the blood volume of most newborns requiring cardiac surgery. We have developed and refined a circuit using commonly available components that can be primed with as little as 265cc. The circuit consists of a Capiox II 0.8m2 lung, with a Terumo 1 OOcc venous reservoir bag and 1/4″ lines. It incorporates a level sensor, bubble detector, recirculation line, arterial GasSTAT™ sensor, and sampling and pressure monitoring lines. A priming volume this low facilitates minimal blood usage in even the smallest infants. This circuit is especially applicable for use with children of Jehovah's Witness parents. It is unique from a safety standpoint in that it not only allows level sensing and bubble detection, but the lung is inverted so the inlet is at the top and the outlet is at the bottom. This configuration causes the lung to act as a bubble trap which may decrease gaseous microemboli. We will describe this “microprime” circuit allowing minimal or no blood usage in this age group, including a review of the literature concerning the safe limits of hemodilution.