Iselin-Chaves Irène A, Willems Sylvie J, Jermann Françoise C, Forster Alain, Adam Stéphane R, Van der Linden Martial
Department of Anesthesiology, University Hospital of Geneva, Switzerland.
Anesthesiology. 2005 Nov;103(5):925-33. doi: 10.1097/00000542-200511000-00005.
This prospective study evaluated memory function during general anesthesia for elective surgery and its relation to depth of hypnotic state. The authors also compared memory function in anesthetized and nonanesthetized subjects.
Words were played for 70 min via headphones to 48 patients (aged 18-70 yr) after induction of general anesthesia for elective surgery. Patients were unpremedicated, and the anesthetic regimen was free. The Bispectral Index (BIS) was recorded throughout the study. Within 36 h after the word presentation, memory was assessed using an auditory word stem completion test with inclusion and exclusion instructions. Memory performance and the contribution of explicit and implicit memory were calculated using the process dissociation procedure. The authors applied the same memory task to a control group of nonanesthetized subjects.
Forty-seven patients received isoflurane, and one patient received propofol for anesthesia. The mean (+/- SD) BIS was 49 +/- 9. There was evidence of memory for words presented during light (BIS 61-80) and adequate anesthesia (BIS 41-60) but not during deep anesthesia (BIS 21-40). The process dissociation procedure showed a significant implicit memory contribution but not reliable explicit memory contribution (mean explicit memory scores 0.05 +/- 0.14, 0.04 +/- 0.09, and 0.05 +/- 0.14; mean automatic influence scores 0.14 +/- 0.12, 0.17 +/- 0.17, and 0.18 +/- 0.21 at BIS 21-40, 41-60, and 61-80, respectively). Compared with anesthetized patients, the memory performance of nonanesthetized subjects was better, with a higher contribution by explicit memory and a comparable contribution by implicit memory.
During general anesthesia for elective surgery, implicit memory persists even in adequate hypnotic states, to a comparable degree as in nonanesthetized subjects.
这项前瞻性研究评估了择期手术全身麻醉期间的记忆功能及其与催眠状态深度的关系。作者还比较了麻醉和未麻醉受试者的记忆功能。
在48例（年龄18 - 70岁）择期手术全身麻醉诱导后，通过耳机播放单词70分钟。患者未使用术前药，麻醉方案自由选择。在整个研究过程中记录脑电双频指数（BIS）。在单词呈现后36小时内，使用包含和排除指令的听觉单词词干补全测试评估记忆。使用过程分离程序计算记忆表现以及外显记忆和内隐记忆的贡献。作者将相同的记忆任务应用于未麻醉受试者的对照组。
47例患者接受异氟醚麻醉，1例患者接受丙泊酚麻醉。平均（±标准差）BIS为49±9。有证据表明在浅麻醉（BIS 61 - 80）和适度麻醉（BIS 41 - 60）期间呈现的单词存在记忆，但在深麻醉（BIS 21 - 40）期间不存在。过程分离程序显示内隐记忆有显著贡献，但外显记忆贡献不可靠（在BIS 21 - 40、41 - 60和61 - 80时，平均外显记忆分数分别为0.05±0.14、0.04±0.09和0.05±0.14；平均自动影响分数分别为0.14±0.12、0.17±0.17和0.18±0.21）。与麻醉患者相比，未麻醉受试者的记忆表现更好，外显记忆贡献更高，内隐记忆贡献相当。
在择期手术全身麻醉期间，即使在适度催眠状态下内隐记忆仍然存在，程度与未麻醉受试者相当。
