Microemboli during Extracorporeal Circulation

Summary

Though filtration of the blood return from the coronary suction line has become widely accepted, there is still some question about the benefits of arterial line filters and combinations of different filter positions. Blood was sampled at 5, 15 and 30 minutes on extracorporeal heart-lung bypass (ECC) and at the end of bypass in 23 patients. All added donor blood was filtered through microporous filters (F₁). In 11 instances a coronary suction line filter (F₂) was in place. Blood was sampled before and after the arterial line filter and in the venous blood. All samples were studied for screen filtration pressure (SFP), and particle count, using apertures from 8 to 120 microns. Simultaneously white blood cell count, platelet count, hematocrit and level of free hemoglobin were done.

The particle counts were summarized in 2 groups: large particles ranging from 12,8 to 120 microns and small particles ranging from 8 to 12.7 microns. The filter combinations F₁ F₂ F₁F₃ and F₁F₂ F₃ were studied. All of the filters were found to be capable of filtering large-sized particles. Slight improvement was seen by using the F₁F₂ F₃ combination. A high gradient for the count of the large particles was found across the arterial line filter. Small particles were noted to derive predominantly from the coronary suction line filter. While the low-flow coronary suction line filter was well capable of removing particles of small size, there was no difference in the number of small particles found proximally and distally to the arterial line filter. Combinations of filters did not improve the results in removing small particles.

Key words

Microemboli - Extracorporeal Circulation