The Effects of Light vs Deep Anesthesia on Postoperative Cognitive Outcomes

 描述（由申请人提供）：由于其患病率、复杂的病因和对患者的潜在严重影响，谵妄是麻醉师和外科医生面临的主要挑战。术后谵妄与较长的住院时间、不良的功能结局、较高的医疗保健费用和增加的死亡率相关。一个相关的现象，术后认知功能下降（POCD）也很常见，并与出院后的功能恶化有关。最近，但有限的证据表明，麻醉深度与术后认知结果不良相关。具体而言，一些研究表明，更深的麻醉水平与术后谵妄和长期认知能力下降的发生率增加有关。事实上，有些人建议，接受手术的老年患者应定期使用麻醉深度监测仪进行监测，以便将麻醉剂或镇静药物滴定至较低水平，以促进更好的术后认知结果。然而，这种做法从未得到验证或证明是可行或安全的。在这项拨款申请中，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，根据处理后的脑电图确定接受“轻度”麻醉还是“深度”麻醉。我们将使用一组经过验证的测试来测量手术前后的认知功能。将使用意识模糊评估方法测量术后谵妄。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，以测量认知功能的轨迹和6周的结局。在这项研究中，我们的目的包括确定在手术过程中将接受大型脊柱手术的患者随机分为深麻醉和浅麻醉的可行性和安全性。具体来说，我们的目标是确定是否可以实行麻醉深度监测仪测量的两种不同的麻醉深度，统一的麻醉供应商在一个大组的老年手术患者。其次，我们将确定一个效应量，用于设计一个未来更大的试验，以确定麻醉深度是否有助于增加不良术后认知结果的发生率，如谵妄或认知下降。第三，我们将确定术前认知障碍水平是否会调节深度麻醉与轻度麻醉对偶发性谵妄或POCD的影响。我们提出的探索性临床试验将是第一个将接受全身麻醉的患者随机分为“浅”麻醉和“深”麻醉，同时测量术后谵妄和认知状态。我们的研究将不仅确定使用两种不同麻醉深度麻醉患者的可行性，而且确定这种方法的安全性。除了测量术后谵妄和POCD，我们还将监测“轻度麻醉”可能的不良后果。我们的研究结果将提供至关重要的信息，以改善围手术期护理的老年患者接受大手术。

 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.