DEPTH OF GENERAL ANESTHESIA AND POSTOPERATIVE MORTALITY

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。最近几篇出版物[1-3]提出手术后一年内的死亡率与麻醉深度有关，麻醉深度是用麻醉药物对大脑皮层的影响来衡量的。随附的一篇社论提请注意，当观察到两种现象并不是一个合理假设的一部分时，提出因果关系是有缺陷的。事实上，迄今为止没有研究令人信服地证明麻醉技术影响围手术期死亡率，如果它被定义为术后30天内的死亡。这甚至适用于与全身麻醉和神经轴麻醉不同的麻醉技术，在这种技术中，麻醉药物对大脑皮层的作用是不需要的，而且通常是最小的。临床经验和研究表明，病人对麻醉的抑制作用更为敏感因此，观察到的麻醉深度与术后一年内死亡率之间的任何关联可能与麻醉本身无关，而是与病情较重的患者生理储备较少这一事实有关，并且在麻醉期间，这可能表现为与健康患者相比，患者的麻醉深度增加。虽然后者是直观的，但只有前瞻性研究才能最终回答麻醉深度是否与1年以上死亡率相关的问题。我们拟对665名接受下腹手术治疗妇科肿瘤的妇女进行这样的研究。我们将给妇女分配三种不同的麻醉技术，并仔细控制麻醉技术、合并症和其他与早期死亡相关的因素，如冠状动脉缺血、肿瘤分期、压力和认知功能。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Several recent publications1-3 have suggested an association between mortality within a year following surgery and depth of anesthesia, measured as anesthetic drug effect on brain cortex. An accompanying editorial 4 draws attention to the pitfalls of suggesting a cause and effect relationship when observing two phenomena that had not been part of a well reasoned hypothesis. In fact, no study to date has convincingly documented that anesthetic technique impacts perioperative mortality, if it is defined as death within up to 30 days after surgery. This is true even for anesthetic techniques as dissimilar as general anesthesia and neuraxial anesthesia, a technique where anesthetic drug effect on the brain cortex is not required and typically minimal. Clinical experience and studies have shown that sick patients are more sensitive to the depressant effects of anesthesia.5 Therefore, any association observed between depth of anesthesia and mortality within a year following surgery may not be related to the anesthesia per se, but rather to the fact that patients who are more ill have less physiologic reserve, and that during anesthesia, this may be expressed as an increased depth of anesthesia in sick patients as compared to healthy patients. While the latter is intuitive, only a prospective study can ultimately answer the question whether anesthetic depth is related to excess 1-year mortality. We propose to perform such a study in 665 women undergoing lower abdominal surgery for gynecologic tumors. We will assign the women to three different anesthetic techniques and carefully control anesthetic technique, comorbid conditions and other factors associated with early mortality such as coronary ischemia, tumor stage, stress, and cognitive function.