Consciousness Disorders after Elective Surgery in Patients with Cerebrovascular Insufficiency

Objective: to study the impact of cerebral hypoxemia on the indicators of neuroinjury, by relying on the diagnosis of post- operative cognitive impairments, and the neuroinjury marker S100b protein and to examine the relationship of postoperative cognitive mpairments. Subjects and methods. Forty-eight non-cardiac surgical and non-neurosurgical patients with verified cerebrovascular disease, who had been operated on under total intravenous anesthesia with propofol and total myoplegia, were examined. Blood S100b protein levels were determined after cerebral hypoxemia detectable by transcranial oximetry. Postoperative delirium was diagnosed by the ICU-CAM test; postoperative cognitive dysfunction was diagnosed according to the Montreal cognitive assessment scale in the periods: 7 days, 1, 3, and 6 months, and 1 year, by using the control group, the Z scores of these indicators were standardized. Results. Cerebral desaturation led to early postoperative disorders, such as delirium and dysfunctions, in 72.7% of the cases. Cerebral saturation parameters correlated moderately, but significantly with neuropsychological indicators at 30 days of the study and 3 months after surgery and just stronger with S100b protein level. The risk of postoperative cognitive impairments in relation to the values of S100b protein was validly predicted in the models of logistic regression and ROC analysis. The rate of early and persistent cognitive dysfunction differed statistically significantly in patients with prior delirium; the logistic regression model validly predicted a relationship between this event and the neuropsychological indicators on 7 days postsurgery. Conclusion. In the patients with cerebrovascular diseases, cerebral hypoxemic episodes are dangerous. When they occur, there is an increased risk of postoperative cognitive impairments, including long-term problems. The above-threshold S100b protein concentration of 0.26 ng/mg is an early predictor of postoperative cognitive disorders.