Opening the cardiac chambers does not make any difference in p300 measurement.

OBJECTIVE

Cognitive brain dysfunction after open heart surgery is a serious complication caused by cardiopulmonary bypass (CPB). The presence of gaseous and/or particulate emboli in the CPB circuit and cerebral hypoperfusion may be the causes of neurologic problems after cardiac operations.

METHODS

In this prospective study we examined 42 consecutive cardiac surgery patients (24 mitral valve replacement [MVR] and 18 coronary artery bypass grafting [CABG] patients). In addition to determination of clinical measurements, cognitive brain function was measured objectively by P300 auditory-evoked potentials before operation, at day 7, and at 4-month follow-up. Electroencephalographic evaluations were also performed.

RESULTS

In preoperative measures there was no difference between the groups (peak latencies in the MVR group were 324 +/- 8 milliseconds; CABG group, 318 +/- 6 milliseconds; P > .05). At day 7, cognitive P300 auditory-evoked potentials were significantly impaired (prolonged) in both groups compared to preoperative values (MVR group, 347 +/- 7 milliseconds; CABG group, 342 +/- 7 milliseconds; P < .05). P300 measurements almost returned to normal at 4-month follow-up (MVR group, 331 +/- 6 milliseconds; CABG group, 319 +/- 8 milliseconds; P > .05 compared to preoperative values). One week and 4 months after surgery no difference between the 2 groups could be found (P > .05).

CONCLUSION

Postoperative patients had prolonged P300 values according to the preoperative measurements and we have not found any difference between the groups whether cardiac chambers were opened or not.