Elimination of fat microemboli during cardiopulmonary bypass

Abstract

Background: Fat emboli have been implicated in cerebral dysfunction after cardiopulmonary bypass (CPB). We sought to identify the source of fat emboli during CPB and devise a technique for their elimination.

Methods: Patients undergoing CPB were prospectively randomized to either cardiotomy suction (n = 7) or cell-saving suction device (n = 6). Blood was collected at various intervals during CPB, and the fat emboli were identified using oil red O stain. These emboli were grouped based on their diameter into 10- to 50-microm and more than 50-microm particles. The number of fat emboli per slide examined was graded according to the following scale: 1 (1 to 10), 2 (11 to 20), 3 (21 to 30), and 4 (> 30 emboli). In the second phase of the experiment, a 21-microm filter was attached in series, distal to the cardiotomy reservoir (n = 6), and fat emboli were quantified.

Results: Blood from the pericardial well was saturated with fat emboli of both sizes. Patients randomized to the cardiotomy suction had a significantly higher number of fat emboli at the end of CPB when compared with those randomized to the cell-saving suction device and dual-filter group. Processed blood from both the cardiotomy reservoir and cell-saving device was noted to have an abundance of fat emboli when compared with blood processed through the dual filters.

Conclusions: Processed blood from both the cardiotomy reservoir and cell-saving device appear to have an abundance of fat emboli that are completely eliminated by using a 21-microm arterial filter in series with the cardiotomy reservoir. This intervention could potentially reduce neurocognitive dysfunction associated with CPB.