Evaluation of cognitive function and P300 in patients undergoing cardiac surgery.

Objective: This study reports cognitive, P300 and MRI changes in the patients undergoing open heart surgery.

Design: 18 patients undergoing open heart surgery were included who were aged > or = 18 years of age and educated at least up to 5th standard. Patients with preoperative neuropsychiatric, and metabolic illnesses were excluded. The operative and post operative events wer recorded Cognitive tests included Mini Mental State examination (MMSE), forward and backward digit span, trail making test (TMT), motor speed and precision test (MSPT), Luria's 3 step, Benton visual retention test (BVRT) and hospital anxiety and depression (HAD). P300 study was carried out using auditory oddball paradigm and recording from Cz, Fz and Pz referred to mastoids. Clinical psychometry, MRI and P300 studies were repeated after 6 weeks.

Results: The median age of the patients was 51 years and 7 were females. Coronary artery bypass graft (15) was done off pump and valve replacement (7) and atrial septal defect (2) were done on pump. Clinical psychometric tests did not change significantly after surgery except BVRT and MSPT were improved significantly after the surgery. The pre and post surgical P300 latency and amplitude were also not different. Follow up MRI in 10 patients also did not reveal any additional findings.

Conclusion: Cognitive decline was not observed after open heart surgery as assessed by clinical psychometry and P300 studies.