Objectives This study draws on advances in Doppler ultrasound bubble sizing to investigate whether high volumes of macro-bubbles entering the brain during cardiac surgery increase the risk of new cerebral microbleeds (CMBs), ischemic MR lesions, or post-operative cognitive decline (POCD). Methods Transcranial Doppler (TCD) ultrasound recordings were analysed to estimate numbers of emboli and macrobubbles (>100 μm) entering the brain during cardiac surgery. Logistic regression was used to explore the hypothesis that emboli characteristics affect the incidence of new brain injuries identified through pre- and post-operative MRI and neuropsychological testing. Results TCD, MRI, and neuropsychological test data were compared between 28 valve and 18 CABG patients. Although valve patients received over twice as many emboli per procedure [median: 1995 vs. 859, p = .004], and seven times as many macro-bubbles [median: 218 vs. 28, p = .001], high volumes of macrobubbles were not found to be significantly associated with new CMBs, new ischaemic lesions, or POCD. The odds of acquiring new CMBs increased by approximately 5% [95% CI: 1 to 10%] for every embolus detected in the first minute after the release of the aortic cross-clamp (AxC). Logistic regression models also confirmed previous findings that cardiopulmonary bypass time and valve surgery were significant predictors for new CMBs (both p = .03). Logistic regression analysis estimated an increase in the odds of acquiring new CMBs of 6% [95% CI: 1 to 12%] for every minute of bypass time over 91 mins. Conclusions This small study provides new information about the properties and numbers of bubbles entering the brain during surgery, but found no evidence to substantiate a direct link between large numbers of macrobubbles and adverse cognitive or MR outcome. Clinical Trial Registration URL - http://www.isrctn.com. Unique identifier: 66022965.

中文翻译：

---

成人心脏手术中栓子的神经学影响

目的 本研究利用多普勒超声气泡大小的进展来研究心脏手术期间进入大脑的大量大气泡是否会增加新发脑微出血 (CMB)、缺血性 MR 病变或术后认知能力下降 (POCD) 的风险. 方法 分析经颅多普勒 (TCD) 超声记录以估计心脏手术期间进入大脑的栓子和大气泡 (>100 μm) 的数量。Logistic 回归用于探索栓子特征影响通过术前和术后 MRI 和神经心理学测试确定的新脑损伤发生率的假设。结果 比较了 28 名瓣膜和 18 名 CABG 患者的 TCD、MRI 和神经心理学测试数据。尽管瓣膜患者每次手术接受的栓子数量是其两倍以上 [中位数：1995 与 859，p = .004] 和大气泡数量的七倍 [中位数：218 对 28，p = .001]，未发现大量大气泡与新的 CMB、新的缺血病变，或 POCD。对于在主动脉交叉钳 (AxC) 释放后的第一分钟内检测到的每个栓子，获得新 CMB 的几率增加了大约 5% [95% CI：1 到 10%]。Logistic 回归模型也证实了之前的研究结果，即体外循环时间和瓣膜手术是新 CMB 的重要预测因素（均 p = .03）。Logistic 回归分析估计，在超过 91 分钟的每分钟旁路时间中，获得新 CMB 的几率增加 6% [95% CI：1 到 12%]。结论 这项小型研究提供了关于手术过程中进入大脑的气泡的特性和数量的新信息，但没有发现证据证实大量大气泡与不良认知或 MR 结果之间存在直接联系。临床试验注册 URL - http://www.isrctn.com。唯一标识符：66022965。