Factors associated with quality of dreams during general anesthesia: a prospective observational study.

Patients frequently report having dreams during general anesthesia, and the dreams are often reported to be pleasant dreams. However, factors associated with the quality of dreams during general anesthesia have not been clarified. The aim of this study was to determine the relationships between the quality of dreams during general anesthesia and perioperative factors. This prospective observational study included patients scheduled for elective surgery under general anesthesia. Preoperative mental status was assessed by the Hospital Anxiety and Depression Scale (HADS). A postoperative interview was carried out in the operating room after recovery from general anesthesia. Dreams and awareness during general anesthesia were assessed by a modified Brice interview. The quality of dreams was classified in accordance with the patient's own opinion as pleasant, indifferent, or unpleasant. A total of 1100 patients were included in the study, and 293 (25.4%) of the patients reported having dreams during anesthesia. Half of the patients who experienced dreams during anesthesia (50.2%, 147/293 patients) reported having a pleasant dream. Multivariate logistic regression analysis revealed that only HADS-depression score of less than 11 was related to pleasant dreams (OR: 3.3 [95% CI 1.3-10.0]).