本研究中涉及人类参与者的所有程序均符合机构和/或国家研究委员会的伦理标准以及 1964 年赫尔辛基宣言及其后来的修正案或类似的伦理标准。根据超声医师的喜好，可以使用扇形阵列（有时通俗地称为“相控阵”）或低频曲线换能器进行检查。对于图形和扫描，曲线探头用于前矢状面视图，而扇形阵列探头用于胃体扫描。探头的商业细节在 材料表中提供。
1.剑突下矢状胃窦视图（又名“剑突下视图”）
<ol><li>仰卧位视图<ol><li>患者体位：将患者置于仰卧位。如果患者无法忍受完全仰卧位，则最多 30 度的抬头是可以接受的选择。</li>
		<li>探头选择：选择任何低频探头（例如，曲线或扇形阵列）（参见 材料表）。</li>
		<li>模式选择：将预设设置为腹部模式。</li>
		<li>探头放置<ol><li>将探头放在矢状面的患者剑突下区域（图1）。</li>
			<li>将探针标记定向至头侧方向。</li>
		</ol></li>
		<li>图像优化<ol><li>将探头从左向右扇动，直到可以在屏幕上看到以下结构：（1）屏幕左侧的肝脏;（2）图像中长轴深处的搏动性主动脉;（2）胃窦位于尾部，深至肝浅缘（图2）。</li>
			<li>确保腹主动脉位于图像的较深边缘。如果看到下腔静脉 （IVC），如果向患者右侧倾斜得太远，则校正超声束角。在这种情况下，在幽门水平而不是胃窦水平上可视化胃。如果发生这种情况，请向左扇动，直到主动脉变得可见。这是分析胃窦的合适位置（图3）。 注意：如果在IVC水平上只看到胃而不是主动脉，则定性超声数据仍然很有价值，但请记住，这种观点对检测“高风险”胃的敏感性较低。在这种情况下，容量评估可能会低估胃容量（图 3）。</li>
			<li>识别固有肌层（低回声，最厚的胃壁层），以确保聚焦在胃上。大而扩张的肠可能被误认为是胃窦（图4）。 注意：胰腺可能在胃窦后方可见（图2）。</li>
		</ol></li>
		<li>图像采集：单击 “获取 ”以保存此超声视图的视频剪辑。</li>
	</ol></li>
	<li>右侧卧位褥疮视图<ol><li>患者体位：将患者置于右侧卧位（图 5）。</li>
		<li>探头选择：按照步骤 1.1.2 操作。</li>
		<li>模式选择：按照步骤 1.1.3 操作。</li>
		<li>探头放置：按照步骤 1.1.4 进行操作。</li>
		<li>图像优化：按照步骤 1.1.5 操作。</li>
		<li>图像采集：按照步骤 1.1.6 操作。</li>
		<li>胃体积的定量估计<ol><li>如果胃窦似乎只含有透明液体，则通过获取如上所述的胃窦图像来量化胃总容积，患者处于 RLD 位置（参见步骤 1.2.5）。</li>
			<li>当在胃窦最大扩张期间获得胃窦的视图时，冻结图像。</li>
			<li>激活追踪工具并沿着代表浆膜的壁的外高回声层 追踪 胃窦的横截面积（图6）。 注意：胃窦面积大于 10 cm2不太可能与正常基线体积一致，并提示“饱腹”。</li>
			<li>点击 保存。</li>
			<li>使用以下公式13 估计胃液体积：胃容量 （mL） = 27 + 14.6 ACSA（以 RLD 为单位）cm2 − 1.28 x 年龄（岁）。 注意：该配方已针对胃窦中的透明液体进行了验证。该公式也在一项针对病态肥胖个体的单独研究中得到了验证14.</li>
		</ol></li>
	</ol></li>
</ol>2. 左上腹 （LUQ） 胃体视图
<ol><li>如果剑突下视图不充分或无法访问，请继续评估左上象限视图（步骤 2.2 和步骤 2.3）。</li>
	<li>LUQ 冠状胃体视图<ol><li>患者体位：遵循步骤 1.1.1。</li>
		<li>探头选择：按照步骤 1.1.2 操作。</li>
		<li>模式选择：按照步骤 1.1.3 操作。</li>
		<li>探头定位<ol><li>将探头放在纵向平面的左腋中线上，方向标记指向患者的头部（图7）。 注意： 当探针标记朝向这个方向时，胸腔将出现在超声扫描仪的左侧，右侧将是腹腔。</li>
		</ol></li>
		<li>图像优化<ol><li>识别脾脏和左半膈肌。脾脏由其圆形的荚膜形状来识别。左半膈肌表现为高回声线，高于脾脏，并随着正常的呼吸周期而移动。</li>
			<li>一旦确定了脾脏，向后扇动以识别肾脏，肾脏将表现为脾脏下方和后方的长方形结构。 注意：脾脏提供的声学窗口比肝脏在右腹部提供的声学窗口少</li>
			<li>一旦确定了这些标志，将换能器向前倾斜以获得胃体的视图（图7）。 注意：解剖结构可能会随着横膈膜的移动而移动。如果可能，请考虑要求患者在进行扫描时短暂屏住呼吸。</li>
		</ol></li>
		<li>按照步骤 1.1.6 获取图像。</li>
	</ol></li>
	<li>LUQ前横胃体视图<ol><li>患者体位：遵循步骤 1.1.1。</li>
		<li>探头选择：按照步骤 1.1.2 操作。</li>
		<li>模式选择：按照步骤 1.1.3 操作。</li>
		<li>探头定位<ol><li>将探头放在患者腹部前表面的锁骨中线附近，就在肋骨的尾部（图8）。为了全面评估胃体，可能需要将探头顺时针旋转至倾斜视图。</li>
		</ol></li>
		<li>图像优化：将探头从颅向尾部扇动，直到看到胃体深入脾脏。</li>
		<li>按照步骤 1.1.6 获取图像。</li>
	</ol></li>
</ol>

胃超声技术减轻围手术期误吸风险

<ol>
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YB 是美国麻醉医师协会床旁超声编辑委员会的编辑，也是 POCUS OpenAnesthesia.org 的部分编辑。SH 是美国麻醉医师协会床旁超声编辑委员会的主编。AP 是美国麻醉医师协会床旁超声编辑委员会的编辑。她还为FujioFilm Sonosite提供咨询工作。

如前所述，胃超声的主要目的是在气道管理或程序镇静之前评估胃内容物并评估风险。提供的协议概述了捕获胃窦和身体图像的两种主要方法，有助于进行这种风险评估。此外，查看代表性结果部分有助于胃超声医师发展图像解释技能。虽然对医疗决策的全面讨论超出了该协议的范围，但本手稿将解决局限性、需要进一步探索的特定临床场景、挑战、未解决的问题以及能力所需的最低培训水平。<...

胃内容物的肺部误吸可引起肺炎、肺炎，甚至死亡1.较高的体积、颗粒物的存在和较高的抽吸酸度已被证明会增加这种情况的严重程度。许多因素有助于指导临床医生评估误吸风险，包括可能减慢胃排空时间的合并症、机械性胃肠道梗阻和最后一次经口摄入的时间。从历史上看，后者仅依赖于对患者病史的评估，这可能是不可靠和不准确的。此外，临床医生的判断力已被证明在诊断饱腹时很差，无法公平2.
2011 年，美国麻醉学会 （ASA） 任命的一个特别工作组首次发布了术前禁食指南，并于 2017 年更新了这些指南 3,4。尽管 ASA 禁食指南是有帮助的，但它们是基于人群的，并非针对特定临床情况量身定制，并且建议对病理改变的患者（例如胃排空延迟或肠梗阻）进一步考虑。此外，这些指南依赖于一位准确的历史学家，并且能够正确回忆起他们最后一次经口摄入量的患者。最后，指南建议的禁食间隔可能不足以确保在紧急情况或紧急情况下空腹。
为了解决已发表的禁食指南中的空白并识别有误吸高风险的患者，胃部诊断性床旁超声 （POCUS） 成像方案已由两个独立的作者组开发和验证：一组由重症监护病房 （ICU） 医生组成，另一组由麻醉师组成。ICU第 5 组专注于需要紧急气管插管的危重患者，并开发了一种通过左上象限 （LUQ） 评估胃来筛查这些患者胃胀气的方法。在LUQ中，作者使用脾脏作为超声窗口，在冠状面和横平面上可视化胃体，以筛查胃膨胀的定性体征。当发现大胃胀气时，作者采取了特殊的气道预防措施，以尽量减少误吸的机会（例如，在诱导全身麻醉和气管插管之前放置鼻胃管进行胃减压[如果没有禁忌证]）。另外，一组专注于围手术期患者的麻醉师开发了一种筛查胃内容物的技术，这在正常胃排空的适当禁食患者中是无法预期的6.该技术涉及将超声探头放置在上腹部的矢状面上以可视化胃窦。该技术既可以定性检测高危胃内容物，也可以在清澈液体的情况下定量估计胃液量。
通过将这两种方案结合成混合方法，本手稿将遵守 I-AIM 框架对胃超声检查的关键步骤进行分类：适应症、采集、图像解释和医疗决策7。然而，由于本特辑的重点是诊断性 POCUS 图像解释，因此本手稿将仅简要介绍图像解释，并将在很大程度上推迟对医疗决策的讨论，因为这超出了本集的范围。
迹象 胃超声至少有四种可能的适应证。首先，在患者胃容量和/或内容物未知或胃容量/内容物病史不可靠的情况下，在插管或程序镇静之前进行胃超声筛查高危胃内容物。在这种情况下，进行胃超声检查以对肺部误吸的可能性进行风险分层，并调整患者的护理以最大限度地降低这种风险。其次，一些重症监护医生使用胃超声来测量接受肠内喂养的患者的胃残余容积 （GRV）8。在这种情况下，评估胃窦有助于诊断肠内喂养不耐受，从而降低吸入性肺炎的风险。最近，胃超声检查已被评估为测量窦横截面积的工具，并显示出与 ICU 患者 GRV 的强相关性9。第三，胃 POCUS 已被用于评估外科手术后患者的肠功能延迟和术后肠梗阻10.第四，在儿科患者中，胃超声已被用于诊断异物摄入和幽门狭窄等病理11.对于胃超声的其他儿科应用，读者可参考其他来源。本文的其余部分将重点介绍成人11 的胃超声检查。
胃超声的禁忌症很少，因为该检查是一种非侵入性检查，对患者的直接伤害可以忽略不计。主要的绝对禁忌症是患者拒绝。相对禁忌症包括以下任何一种：（1） 通常扫描窗口区域的敷料/伤口;（2）由于患者的血流动力学或临床状态迅速恶化而没有时间尝试检查;（3）胃饱的预测试概率非常高或非常低。幸运的是，干预敷料/伤口的存在有时可以通过选择替代超声检查窗口来解决。例如，如果前腹入路受阻，可以尝试左侧位，反之亦然。时间不足也可以通过刻意练习来控制，因为研究表明，胃超声可以在专家手中迅速进行12.最后，在某些情况下，胃饱腹的验前概率要么非常低（例如，健康患者在手术前适当禁食）要么非常高（例如，患者出现已知的固定肠梗阻）。在这种情况下，胃超声是相对禁忌的，因为该测试与所有诊断测试一样，并不完美，并且有可能产生假阳性和假阴性结果，从而导致患者走向不适当的方向。
收购 对于采集，建议从剑突下矢状面入路开始，以可视化胃窦。胃窦是测量胃内容物的最佳解剖位置，因为它具有一致的浅表位置。它构成了胃中最依赖的部分，在大多数患者中可以快速识别6.此外，胃窦随着内容物的增加而线性扩张，使其成为定性评估胃内容物的合适靶标，并建议胃抽吸的风险分层6。如果前矢状窗无法触及（例如，由于伤口/敷料）或提供不确定的数据，左侧侧窗可以提供有关患者胃内容物的有用定性数据。
关于图像解释和医疗决策，该手稿回顾了一系列潜在结果，并解释了胃超声如何在不同的患者群体中协同使用。最后，将描述这些方法的常见缺陷和局限性。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>High Frequency Ultrasound Probe (HFL38xp)</td>
			<td>SonoSite (FujiFilm)</td>
			<td>P16038</td>
			<td></td>
		</tr>
		<tr>
			<td>Low Frequency Ultrasound Probe (C35xp)</td>
			<td>SonoSite (FujiFilm)</td>
			<td>P19617</td>
			<td></td>
		</tr>
		<tr>
			<td>SonoSite X-porte Ultrasound</td>
			<td>SonoSite (FujiFilm)</td>
			<td>P19220</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasound Gel</td>
			<td>AquaSonic</td>
			<td>PLI 01-08</td>
			<td></td>
		</tr>
	</tbody>
</table>

gastric point of care ultrasound in adults: image acquisition and interpretation

在过去的二十年中，诊断性床旁超声 （POCUS） 已成为一种快速且无创的床边工具，用于解决与胃内容物相关的临床查询。对于即将接受镇静和/或气管插管的患者，一个新出现的问题：患者胃内容物误吸的风险增加。胃内容物吸入肺部会造成严重且可能危及生命的并发症。当胃被认为是“饱”时，这种情况会更频繁地发生，并且可能受到用于气道管理的技术的影响，从而有可能预防。为了降低围手术期误吸的风险，两个不同的医学专业（麻醉学和重症监护医学）独立开发了利用超声检查来识别需要“全胃”预防措施的患者的技术。由于这些不同的专业，每个小组的工作在各自领域之外仍然相对陌生。本文介绍了两种胃超声技术。此外，它还解释了当其中一种方法不足时，这些方法如何相互补充。关于图像采集，本文涵盖以下主题：适应症和禁忌症、适当探头的选择、患者定位和故障排除。本文还深入探讨了图像解释，并附有示例图像。此外，它还演示了如何采用这两种技术中的一种来估计胃液量。最后，本文简要讨论了基于本次检查结果的医疗决策。

Pulmonary aspiration of gastric contents can cause pneumonitis, pneumonia, and even death1. Higher volume, the presence of particulate matter, and higher acidity of aspirate have been shown to increase the severity of this scenario. Numerous factors help guide a clinician in assessing the risk of aspiration, including comorbid diseases that may slow gastric emptying times, mechanical gastrointestinal obstruction, and timing of the last oral intake. Historically, the latter relies solely on an assessment of the patient&#39;s history, which can be unreliable and inaccurate. In addition, clinician judgment has been shown to be poor to fair at diagnosing a full stomach2.
In 2011, a special task force appointed by the American Society of Anesthesiology (ASA) first published the guidelines for preoperative fasting, and these were updated in 20173,4. Although the ASA fasting guidelines are helpful, they are population-based and not tailored to specific clinical situations, and they recommend further consideration for patients with altered pathology, such as delayed gastric emptying or bowel obstruction. Furthermore, these guidelines rely on a patient who is an accurate historian and can correctly recall their last oral intake. Finally, the guidelines&#39; recommended fasting intervals may not be sufficient to ensure an empty stomach in urgent or emergency situations.
To address gaps in the published fasting guidelines and identify patients at high risk of aspiration, diagnostic point-of-care ultrasound (POCUS) imaging protocols of the stomach have been developed and validated by two separate author groups: one group consisting of intensive care unit (ICU) physicians, and the other of anesthesiologists. The ICU group5 focused on critically ill patients requiring urgent endotracheal intubation and developed a method to screen these patients for gross gastric distension by evaluating the stomach through the left upper quadrant (LUQ). In the LUQ, the authors used the spleen as a sonographic window to visualize the gastric body in the coronal and transverse planes to screen for qualitative signs of gastric distension. When gross gastric distension was identified, the authors took special airway precautions to minimize the chance of aspiration (e.g., by placing a nasogastric tube for gastric decompression [if not contraindicated] before induction of general anesthesia and endotracheal intubation). Separately, a group of anesthesiologists focused on perioperative patients developed a technique for screening stomach contents that would not be expected in properly fasted patients with normal gastric emptying6. This technique involves placing the ultrasound probe in a sagittal plane in the epigastrium to visualize the gastric antrum. The technique allows for both qualitative detection of high-risk stomach contents and, in cases of clear fluid, quantitative estimation of gastric fluid volume.
By combining these two protocols into a hybrid approach, this manuscript will abide by the I-AIM framework to categorize the key steps in gastric ultrasonography: indications, acquisition, image interpretation, and medical decision-making7. However, since this Special Collection is focused on diagnostic POCUS image interpretation, this manuscript will only briefly cover image interpretation and will largely defer the discussion of medical decision-making, as this falls outside the scope of this Collection.
Indications 
Gastric ultrasound has at least four possible indications. First, gastric ultrasound is indicated to screen for high-risk stomach contents prior to intubation or procedural sedation in situations when the patient&#39;s stomach volume and/or contents are either unknown or the history about gastric volume/contents is unreliable. In this setting, the gastric ultrasound exam is performed to risk-stratify the likelihood of pulmonary aspiration and adjust the patient&#39;s care to minimize this risk. Second, some intensivists have used gastric ultrasound to measure gastric residual volumes (GRV) in patients receiving enteral feeding8. In this case, assessing the gastric antrum can aid in the diagnosis of enteral feed intolerance and subsequently decrease the risk of aspiration pneumonia. Recently, gastric ultrasonography has been evaluated as a tool to measure antral cross-sectional area and has shown a strong correlation with GRV in ICU patients9. Third, gastric POCUS has been used to assess delayed bowel function and post-operative ileus in patients following surgical procedures10. Fourth, in pediatric patients, gastric ultrasound has been utilized to diagnose foreign body ingestion and pathologies such as pyloric stenosis11. For other pediatric applications of gastric ultrasound, readers are referred to other sources. The remainder of this article will focus on gastric ultrasound in adults11.
There are very few contraindications to gastric ultrasound because the exam is a non-invasive test that poses negligible direct harm to patients. The main absolute contraindication is patient refusal. Relative contraindications include any of the following: (1) dressings/wounds in the area of the usual scanning windows; (2) a lack of time to attempt the exam due to rapid deterioration of a patient&#39;s hemodynamic or clinical status; and (3) a very high or very low pre-test probability of a full stomach. Fortunately, the presence of intervening dressings/wounds can sometimes be addressed by choosing an alternate sonographic window. For example, if the anterior abdominal approach is obstructed, one can attempt a left lateral view and vice versa. A shortage of time can also be managed through deliberate practice, as studies have shown that gastric ultrasound can be performed expeditiously in expert hands12. Finally, there are cases where the pre-test probability of a full stomach is either very low (e.g., a healthy patient properly fasted for surgery) or very high (e.g., a patient presenting with a known, fixed intestinal obstruction). In such cases, gastric ultrasound is relatively contraindicated because the test - like all diagnostic tests - is imperfect and has the potential to generate false positive and false negative results that can lead patients in an inappropriate direction.
Acquisition 
For acquisition, it is recommended to begin with the subxiphoid sagittal approach to visualize the gastric antrum. The antrum represents an optimal anatomical location to measure gastric contents due to its consistent and superficial location. It constitutes the most dependent portion of the stomach and can be quickly identified in most patients6. Additionally, the gastric antrum dilates in a linear fashion as its contents increase, making it a suitable target for qualitatively assessing stomach contents and suggesting a risk stratification of gastric aspiration6. If the anterior sagittal window is not accessible (e.g., due to wounds/dressings) or provides indeterminate data, the left lateral window may offer useful qualitative data regarding a patient&#39;s gastric contents.
Regarding image interpretation and medical decision-making, the manuscript reviews a range of potential outcomes and explains how gastric ultrasound can be collaboratively used in distinct patient populations. Finally, the common pitfalls and limitations of these methods will be described.

作者聚焦：用于围手术期护理中胃内容物评估和风险分层的床旁超声 

成人胃旁超声：图像采集和解释

Current NPO guidelines do not specifically address patients with delayed gastric emptying or bowel obstruction. Utilizing point of care ultrasound to assess the gastric contents allows providers to have more accurate information regarding these patients, and appropriately risk stratify their likelihood of pulmonary aspiration. These protocols will hopefully allow perioperative practitioners to better assess the gastric contents of patients requiring sedation or endotracheal intubation.With more accurate data, the practitioner will be better able to risk stratify and minimize the likelihood of pulmonary aspiration. Portions of this protocol will be utilized to research the gastric emptying patterns of unique patient populations, such as those with diabetes, bowel obstructions, hiatal hernias, or who are taking the novel medication glucagon-like peptide-1 receptor agonists.

为确保胃窦的准确可视化，有必要探查足够深以识别主动脉。相反，检测 IVC 将扫描置于胃幽门水平，导致结果低估了真正的胃内容物。虽然胃幽门水平的诊断效用仍然存在，但与胃窦视图相比，解释起来不那么简单（图 3）。因此，一项关键任务是扫描大血管并区分胃窦和幽门（图9）。主动脉可通过其厚而脉动的壁来识别，与IVC不同。必要时，可利?...

Watch this Scientific Journal Video about Point-of-Care Ultrasound for Gastric Content Assessment and Risk Stratification in Perioperative Care at JoVE.com

该协议介绍了两种在胃超声检查中获取图像的方法。此外，还提供了解释这些信息以帮助医疗决策的提示。

Over the past two decades, diagnostic point-of-care ultrasound (POCUS) has emerged as a rapid and non-invasive bedside tool for addressing clinical ...

目前的 NPO 指南并未专门针对胃排空延迟或肠梗阻患者。利用床旁超声评估胃内容物，使提供者能够获得有关这些患者的更准确信息，并适当地对他们进行肺部误吸的可能性进行风险分层。这些方案有望使围手术期从业者更好地评估需要镇静或气管插管的患者的胃内容物。有了更准确的数据，从业者将能够更好地进行风险分层并最大限度地减少肺部误吸的可能性。该协议的部分内容将用于研究独特患者群体的胃排空模式，例如患有糖尿病、肠梗阻、食管裂孔疝或正在服用新型药物胰高血糖素样肽-1 受体激动剂的患者。

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Gastric Point of Care Ultrasound in Adults: Image Acquisition and Interpretation

1.9K 次观看.  George Washington University. 目前的 NPO 指南并未专门针对胃排空延迟或肠梗阻患者。利用床旁超声评估胃内容物，使提供者能够获得有关这些患者的更准确信息，并适当地对他们进行肺部误吸的可能性进行风险分层。这些方案有望使围手术期从业者更好地评估需要镇静或气管插管的患者的胃内容物。有了更准确的数据，从业者将能够更好地进行风险分层并最大限度地减少肺部误吸的可能性。该协?...