In-line leukocyte filtration during bypass. Clinical results from a randomized prospective trial

Leukocyte mediated pulmonary injury may delay recovery after cardiac surgery, and leukocyte depletion during bypass has been suggested. Two groups of patients were randomly, prospectively assigned from 50 sequential patients to undergo open heart surgery using cardiopulmonary bypass, either with (n = 25) or without (n = 25) leukocyte filters. The two groups were not significantly different regarding age, gender, race, pre-operative ejection fraction, pump time, or cross-clamp time. Post operative arterial blood gases (pO2: 173 +/- 66 vs 192 +/- 107; pCO2: 30.2 +/- 8.2 vs 30.8 +/- 8.0), pulmonary vascular resistance (PVR 105 +/- 45 vs 112 +/- 50 dyne cm-5), time on ventilator (17.8 +/- 6.4 vs 19.7 +/- 8.6 hr), and length of hospital stay (7.65 +/- 4.57 vs 8.52 +/- 5.87 days) were not different between groups (mean +/- SD, with vs without filters, respectively). Arterial oxygenation was somewhat poorer, and PVR was somewhat lower in the leukocyte filtered group. However, these trends did not produce significant decreases in total ventilator time or length of hospital stay. In-line filtration did remove leukocytes, but did not reduce circulating leukocyte count. In effect, leukocyte filtration produced an effective leukocyte concentration at the filter site. These data do not support routine incorporation of in-line leukocyte filtration during bypass.