Psychiatric complications following cardiac surgery: Part II. A working hypothesis—the chemical approach

Abstract

Summary The increased incidence of psychiatric complications following open-heart surgery with the use of cardiopulmonary bypass presents an interesting speculation in view of the extremely high level of circulating amines resulting from the use of the bypass apparatus. Abnormal metabolic pathways of all amines can produce hallucinogenic substances. Further, direct oxygenation of blood may enhance the formation of large amounts of adrenochrome in the bypass apparatus with its effects on the central nervous system detected as the patient recovers. Enzymatic aberrations allowing for abnormal methylation could explain the higher incidence seen and may be a heredity factor, explaining the relationship of complications to a familial history of mental illness and a previous history of emotional problems. The lack of symptoms in children may be related to differences in the need, metabolic pathways, or ability to handle the biological amines. This may explain the “paradoxical reaction” one sees with the use of amphetamines or antidepressant compounds used in the treatment of hyperkinetic children. The role of the phenothiazines used for the successful management of patients with psychiatric complications may present another clue to etiology.