POSTOPERATIVE DELIRIUM IN CARDIAC SURGERY

Abstract

Currently, cardiovascular diseases remain the leading ones in mortality among other causes. Increasingly, interventional methods are used in their treatment. In the postoperative period, complications in the form of somatogenic psychoses, including postoperative delirium, are not uncommon. The purpose of the review is to study the prevalence, pathophysiological hypotheses and mechanisms of delirium, as well as risk factors and outcomes associated with the development of this complication in cardiac surgery. Materials and methods. Information was searched in the PubMed database by Key words: delirium, postoperative period, cognitive dysfunction, cardiac surgery. The search yielded a total of 57 results. During the review of titles and abstracts, 47 articles were selected for detailed consideration. Results. There are three forms of postoperative delirium: hyperactive, hypoactive, mixed. The frequency of confused mental state development after heart surgery is 26-52%, and its hypoactive form dominates. Delirium is considered as an acutely developing, reversible nonspecific syndrome of multifactorial etiology, characterized by a combined disorder of consciousness and attention, perception, thinking, memory, sleep–wake rhythm, psychomotor disorders with alternating hypo- and hyperactivity. The factors influencing the onset of delirium include increased inflammatory response, changes in the concentration of neurotransmitters (especially acetylcholine), electrolyte and metabolic and hemodynamic disorders, and the presence of a genetic predisposition. There is a number of preoperative, intraoperative and postoperative risk factors for the development of delirium in patients after cardiac surgery. Delirium after cardiac surgery is associated with such adverse outcomes as increased mortality, stroke risk, sepsis development, more frequent repeated hospitalizations and persistent severe cognitive impairment during 1 year after the surgery. Differential diagnosis is carried out for depression, dementia, psychogenic psychoses and organic lesions of the central nervous system. Delirium treatment is aimed at eliminating the underlying cause; it includes supportive therapy, correction of agitation, elimination of water-electrolyte disorders and elimination of provoking factors (discontinuation of the causal drug), replenishment of nutritional deficiencies, vitamins B12 or B1 (thiamine) with adequate dietary regimen and fluid intake. Conclusions. Taking into consideration that delirium is a dangerous condition that develops in the postoperative period, the following main provisions are important: 1) eliminate correctable risk factors in every period of surgical intervention in outpatient and inpatient settings; 2) carry out drug prevention and, if necessary, delirium therapy; 3) increase alertness regarding the occurrence of confused mental state episodes in patients in the postoperative period; 4) conduct screening in patients over the age of 65 to assess the main risk factors of delirium, cognitive impairment development.