[The effect of two different glycemic management protocols on postoperative cognitive dysfunction in coronary artery bypass surgery]

Abstract

Introduction: Postoperative cognitive dysfunction (POCD) is an adverse outcome of surgery that is more common after open heart procedures. The aim of this study is to investigate the role of tightly controlled blood glucose levels during coronary artery surgery on early and late cognitive decline.

Methods: 40 patients older than 50 years undergoing elective coronary surgery were randomized into two groups. In the "Tight Control" group (GI), the glycemia was maintained between 80 and 120mg·dL^-1 while in the "Liberal" group (GII), it ranged between 80-180mg·dL^-1. A neuropsychological test battery was performed three times: baseline before surgery and follow-up first and 12th weeks, postoperatively. POCD was defined as a drop of one standard deviation from baseline on two or more tests.

Results: At the postoperative first week, neurocognitive tests showed that 10 patients in the GI and 11 patients in GII had POCD. The incidence of early POCD was similar between groups. However the late assessment revealed that cognitive dysfunction persisted in five patients in the GII whereas none was rated as cognitively impaired in GI (p=0.047).

Conclusion: We suggest that tight perioperative glycemic control in coronary surgery may play a role in preventing persistent cognitive impairment.

Keywords: Cirurgia de revascularização do miocárdio; Cognitive dysfunction; Controle glicêmico; Coronary artery bypass surgery; Disfunção cognitiva; Glucose control.