The Effects of Light vs Deep Anesthesia on Postoperative Cognitive Outcomes

 描述(由申请人提供)：精神错乱是麻醉师和外科医生面临的主要挑战，因为它的流行，复杂的病因，以及对患者的潜在严重影响。术后精神错乱与较长的住院时间、较差的功能结果、较高的医疗费用和较高的死亡率有关。一个相关的现象是，术后认知功能下降(POCD)也很常见，并与出院后的功能下降有关。最近，但有限的证据表明，麻醉深度与术后认知结果差有关。具体地说，几项研究表明，麻醉程度越深，术后精神错乱和长期认知能力下降的发生率就越高。事实上，一些人建议，接受手术的老年患者应该定期使用麻醉深度监测器进行监测，以便将麻醉剂或镇静剂滴定到较轻的水平，以促进更好的术后认知结果。然而，这种做法从未被证实或证明是可行或安全的。在这项拨款提案中，我们将在一组接受大型脊柱手术的老年患者中进行随机对照试验，接受由处理过的脑电确定的“轻”或“深”麻醉水平。我们将使用一系列经过验证的测试来衡量手术前后的认知功能。术后精神错乱将使用迷惑评估法进行测量。与大多数以前的横断面研究不同，我们将进行术前和系列随访评估，以衡量认知功能的轨迹和6周的结果。在这项研究中，我们的目标包括确定接受大型脊柱手术的患者在手术期间接受深度麻醉和轻度麻醉的可行性和安全性。具体地说，我们的目标是确定通过麻醉深度监测器测量的两种不同的麻醉深度是否可以由许多麻醉提供者在一大群老年手术患者中统一进行。其次，我们将确定一个效应大小，以设计一项未来的更大规模的试验，以确定麻醉深度是否有助于增加术后不良认知结果的发生率，如精神错乱或认知能力下降。第三，我们将确定术前认知障碍水平是否缓和了深度麻醉与轻度麻醉对偶发性妄想或POCD的影响。我们提出的探索性临床试验将是第一个随机选择接受全身麻醉的患者，分别接受“浅”和“深”麻醉，同时测量术后精神错乱和认知状态。我们的研究不仅将确定使用两种不同水平的麻醉深度麻醉患者的可行性，而且还将确定这种方法的安全性。除了测量术后精神错乱和POCD外，我们还将监测“光麻醉”可能产生的不良后果。我们的研究结果将为改善接受大手术的老年患者的围手术期护理提供至关重要的信息。

 DESCRIPTION (provided by applicant): Delirium is a major challenge facing anesthesiologists and surgeons due to its prevalence, complex etiology, and potential severe impact on patients. Postoperative delirium is associated with longer hospital stays, poor functional outcomes, higher healthcare costs, and increased mortality. A related phenomenon, postoperative cognitive decline (POCD) is also common and associated with worse functioning after hospital discharge. There is recent, but limited evidence to suggest that anesthetic depth is associated with poor postoperative cognitive outcomes. Specifically, several studies suggest that deeper level of anesthesia is associated with increased incidence of postoperative delirium and longer-term cognitive decline. In fact, some suggest that older patients undergoing surgery should routinely be monitored with an anesthetic depth monitor to allow the titration of anesthetics or sedation medications to lighter levels to promote better postoperative cognitive outcomes. However, such a practice has never been validated or proven to be feasible or safe. In this grant proposal, we will undertake a randomized control trial in a cohort of older patients undergoing major spine surgery to receive either a "light" vs. "deep" level of anesthesia as determined by a processed electroencephalogram. We will use a validated battery of tests to measure cognitive function before and after surgery. Postoperative delirium will be measured using the Confusion Assessment Method. In contrast to most previous studies that were cross-sectional, we will perform preoperative and serial follow-up assessments to measure the trajectory of cognitive function, and 6-week outcomes. In this study, our aims include determining the feasibility and safety of randomizing patients undergoing major spine surgery to receive deep vs. light anesthetic levels during surgery. Specifically we aim to determine whether two different anesthetic depths as measured by an anesthetic depth monitor can be practiced uniformly by a number of anesthesia providers across a large group of older surgical patients. Second, we will determine an effect size for designing a future larger trial to determine whether anesthetic depth contributes to an increased incidence of adverse postoperative cognitive outcomes as measured by delirium or cognitive decline. Third, we will determine whether preoperative level of cognitive impairment moderates the effect of deep vs. light levels of anesthesia on incident delirium or POCD. Our proposed exploratory clinical trial will be the first to randomize patients undergoing general anesthesia to receive either "light" vs. "deep" levels of anesthesia with simultaneous measurements of postoperative delirium and cognitive status. Our study will determine not only the feasibility of anesthetizing patients using two different levels of anesthetc depth, but also the safety of such an approach. In addition to measuring postoperative delirium and POCD, we will also be monitoring possible adverse consequences of "light anesthesia". Our study results will provide critically important information to improve perioperative care to the older patients undergoing major surgery.