Although the incidence of delirium after cardiac surgery is high, it is not sufficiently recognized. The long-term effects of delirium are likely to be underestimated. In this study, the investigators aimed to examine the relationship between optic nerve sheath diameter and postoperative delirium in open hearth surgery.

Postoperative delirium is characterized by widespread brain involvement and its incidence is between 6% and 30%. It appears twice as often after cardiac and vascular surgery than other types of surgery. The correlation between optic nerve sheath diameter (ONSD) and invasive intracranial pressure measurement is excellent. ONSD reduction has the potential to indicate intracranial hypoperfusion causing delirium. In this observational study, patients aged 18 years and over who will undergo open heart surgery will be examined. ONSD will be measured using ultrasound five times in the perioperative period (t0: pre-induction, t1: post-induction, t2: onset of cardiopulmonary bypass (CPB), t3: post-CPB, and t4: post-ICU admission). The Confusion Assessment Method for the ICU (CAM-ICU) test will be used to examine delirium in the ICU. Whether the change in ONSD is an independent risk factor for delirium will be evaluated.

Inclusion Criteria:

• ≥18 year old
• Elective open heart surgery

Exclusion Criteria:

• psychiatric illness
• neurological disease
• ophthalmic disease
• previous eye surgery
• perioperative cerebrovascular disease
• need for postoperative intraaortic balloon or extracorporeal support system

Patients over the age of 18 who will undergo elective open heart surgery will be included in the study.