Arterial microemboli, which may be reduced by arterial line filtration, have been proposed as a factor con tributing to cardiopulmonary bypass (CPB)-related cerebral dysfunction. The authors report on a study investi gating the effects of arterial line fil tration on the incidence of microemboli and the neuropsycho > 50mmHg, flow 1.8-2.4L/m2/min) was standardized and continuously monitored. Transcranial Doppler measured middle cerebral artery blood velocity and the incidence of microembolic events (MEE). Forty patients (median age fifty-six years, range forty-three to seventy) have completed the protocol. MEE oc curred in all patients during aortic cannulation and at inception of by pass. During bypass, patients with filtered CPB had fewer MEE (0-10 per thirty minutes) than nonfiltered CPB patients (30- > 250 per thirty minutes) did. Seven of 20 nonfiltered CPB patients showed soft neurologic signs on the first postoperative day compared with 3/20 in the filtered CPB group (P = 0.27, Fisher's). The filtered CPB patients performed bet ter on a verbal memory test (P < 0.01, Wilcoxon) at eight weeks than the nonfiltered CPB group did.
