[Awareness with recall during general anesthesia: analysis of 2015 cases]

To investigate the incidence of awareness with recall during general anesthesia in elective operation with modern anesthetic methods and to analyze the risk factors thereof.

2025 patients, 1001 males and 1024 females, aged 53 +/- 16, underwent general anesthesia during different kinds of elective operation. Interview was conducted 1 - 3 days postoperatively to survey the incidence of awareness during operation. Two weeks later follow-up was conducted again to know if sequelae existed.

Twenty-eight patients (1.4%) were identified as with awareness. Multiple regression analysis showed that awareness during operation was associated with being female (OR = 2.836, 95% CI = 1.81 - 6.810), use of laryngeal mask airway (LMA, OR = 19.609, 95% CI = 3.918 - 98.740), not use volatile anesthetics at a time or continuously during maintenance of anesthesia (OR = 3.084, 95% CI = 1.246 - 7.629), and intra-operative blood pressure fluctuation (OR = 10.430, 95% CI = 3.918 - 27.763), Premedicated patients had lower incidence of awareness during operation (OR = 0.326, 95% CI = 0.110 - 0.965). Twenty-three of the 28 patients with awareness during operation (82%) had auditory perception, 2 (7%) had both auditory and visual perception, 7 felt pain at different degrees, and 10 (36%) felt anxiety during operation. After effects appeared in 6 of the 28 patients (21%).

Awareness occurs in some patients undergoing elective operation. Being female, use of LMA, not using volatile anesthetics at a time or continuously during maintenance of anesthesia, and intra-operative blood pressure fluctuation are risk factors. Premedication may help prevent awareness during operation.