['Postoperative cognitive dysfunction (POCD) is a well-known complication after cardiac surgery and may cause permanent disabilities with severe consequences for quality of life. The objectives of this study were, first, to estimate the frequency of POCD after on-pump cardiac surgery in patients randomized to remifentanil- or sufentanil-based anesthesia and, second, to evaluate the association between POCD and quality of recovery and perioperative hemodynamics, respectively.', 'Randomized study.', 'Postoperative cardiac recovery unit, University Hospital.', 'Sixty patients with ischemic heart disease scheduled for elective coronary artery bypass grafting ± aortic valve replacement.', 'Randomized to either remifentanil or sufentanil anesthesia as basis opioid. Postoperative pain management consisted of morphine in both groups.', 'Cognitive functioning evaluated preoperatively and on the 1st, 4th, and 30th postoperative day using the cognitive test from the Palo Alto Veterans Affairs Hospital. Perioperative invasive hemodynamics and the quality of recovery was evaluated by means of invasive measurements and an intensive care unit discharge score.', 'No difference between opioids in POCD at any time. A negative correlation was found between preoperative cognitive function and POCD on the first postoperative day (r=-0.47; P=.0002). The fraction of patients with POCD on the first postoperative day was statistically greater in patients with more than 15minutes of Svo2 <60 (P=.037; χ(2) test). Among patients with postoperative ventilation time exceeding 300minutes, more patients had POCD on postoperative day 4 (P=.002).'] Is ultrashort acting remifentanil superior to long-acting sufentanil in preserving cognitive function-a randomized study?