Metabolic disturbance affects postoperative cognitive function in patients undergoing cardiopulmonary bypass.

OBJECTIVES Postoperative delirium is a common neuropsychiatric syndrome after coronary artery bypass grafting (CABG). We aimed to assess and compare clinical outcomes of CABG patients with delirium with a specific focus on the blood biochemical parameters. METHODS This investigation was carried out on the 90 eligible patients undergoing CABG. Delirium was measured using the Neecham confusion scale and assessed patients were divided into two groups of delirium (n = 43) and non-delirium (n = 47). Preoperative variables and intraoperative and postoperative outcomes were compared. RESULTS Delirium patients were older (p = 0.003) and had longer intubation time (p = 0.003). Non-delirium patients obtained a significantly higher Neecham confusion score (p = 0.001), and delirium patients experienced a hyperglycemic state at intraoperative (p = 0.004), intubation (p = 0.03), and extubation time (p = 0.02). Lower value of pH was seen at intubation (p = 0.03) and extubation periods (p = 0.001) in delirium group. A significant difference in base excess was observed between two groups at intubation (p = 0.04) and extubation periods (p = 0.004). Potassium level showed a significant decrease in delirium group at intubation (p = 0.01) and extubation periods (p = 0.001). Multivariate regression indicated that aging (OR = 1.08, p = 0.01), narcotic consumption (OR = 3.27, p = 0.05), DM (OR = 3.03, p=0.03), and prolonged intubation (OR = 1.18, p = 0.03) are predictors of delirium. Postoperative hyperglycemia (OR = 1.01, p = 0.002), low pH value (OR = 2.62, p = 0.02), and low potassium level (OR = 3.25, p = 0.03) are associated with development of delirium. CONCLUSIONS Postoperative metabolic disturbance and electrolyte imbalances are closely related to the development of delirium after CABG and need to be considered more carefully. Aging, DM, and preoperative use of narcotics are strong predictors of delirium following CABG.