Berg Cameron, Doniger Stephanie J, Zaia Brita, Williams Sarah R
North Memorial Health Care, Department of Emergency Medicine, Robbinsdale, Minnesota.
University of California, San Francisco Benioff Children's Hospital Oakland, Division of Emergency Medicine, Oakland, California.
West J Emerg Med. 2015 Mar;16(2):263-8. doi: 10.5811/westjem.2015.1.24150. Epub 2015 Mar 6.
Point-of-care ocular ultrasound (US) is a valuable tool for the evaluation of traumatic ocular injuries. Conventionally, any maneuver that may increase intraocular pressure (IOP) is relatively contraindicated in the setting of globe rupture. Some authors have cautioned against the use of US in these scenarios because of a theoretical concern that an US examination may cause or exacerbate the extrusion of intraocular contents. This study set out to investigate whether ocular US affects IOP. The secondary objective was to validate the intraocular pressure measurements obtained with the Diaton® as compared with standard applanation techniques (the Tono-Pen®).
We enrolled a convenience sample of healthy adult volunteers. We obtained the baseline IOP for each patient by using a transpalpebral tonometer. Ocular US was then performed on each subject using a high-frequency linear array transducer, and a second IOP was obtained during the US examination. A third IOP measurement was obtained following the completion of the US examination. To validate transpalpebral measurement, a subset of subjects also underwent traditional transcorneal applanation tonometry prior to the US examination as a baseline measurement. In a subset of 10 patients, we obtained baseline pre-ultrasound IOP measurements with the Diaton® and Tono-Pen®, and then compared them.
The study included 40 subjects. IOP values during ocular US examination were slightly greater than baseline (average +1.8mmHg, p=0.01). Post-US examination IOP values were not significantly different than baseline (average -0.15mmHg, p=0.42). In a subset of 10 subjects, IOP values were not significantly different between transpalpebral and transcorneal tonometry (average +0.03mmHg, p=0.07).
In healthy volunteer subjects, point-of-care ocular US causes a small and transient increase in IOP. We also showed no difference between the Diaton® and Tono-Pen® methods of IOP measurement. Overall, the resulting change in IOP with US transducer placement is considerably less than the mean diurnal variation in healthy subjects, or pressure generated by physical examination, and is therefore unlikely to be clinically significant. However, it is important to take caution when performing ocular ultrasound, since it is unclear what the change in IOP would be in patients with ocular trauma.
床旁眼部超声检查是评估外伤性眼损伤的一项重要工具。传统上，在眼球破裂的情况下，任何可能增加眼压（IOP）的操作都是相对禁忌的。一些作者曾告诫不要在这些情况下使用超声检查，因为从理论上讲，担心超声检查可能会导致或加剧眼内容物的挤出。本研究旨在调查眼部超声检查是否会影响眼压。次要目的是验证与标准压平技术（Tono-Pen®）相比，使用Diaton®获得的眼压测量值。
我们纳入了一个方便样本的健康成年志愿者。我们通过经睑眼压计为每位患者获取基线眼压。然后使用高频线性阵列换能器对每个受试者进行眼部超声检查，并在超声检查期间获得第二次眼压测量值。在超声检查完成后获得第三次眼压测量值。为了验证经睑测量，一部分受试者在超声检查前还接受了传统的经角膜压平眼压测量作为基线测量。在10名患者的子集中，我们使用Diaton®和Tono-Pen®获得超声检查前的基线眼压测量值，然后进行比较。
该研究包括40名受试者。眼部超声检查期间的眼压值略高于基线（平均升高1.8mmHg，p = 0.01）。超声检查后眼压值与基线无显著差异（平均降低0.15mmHg，p = 0.42）。在10名受试者的子集中，经睑眼压测量和经角膜眼压测量之间的眼压值无显著差异（平均升高0.03mmHg，p = 0.07）。
在健康志愿者受试者中，床旁眼部超声检查会导致眼压出现小幅度的短暂升高。我们还发现Diaton®和Tono-Pen®眼压测量方法之间没有差异。总体而言，超声换能器放置导致的眼压变化远小于健康受试者的平均昼夜变化或体格检查产生的压力，因此在临床上不太可能具有显著意义。然而，在进行眼部超声检查时谨慎操作很重要，因为目前尚不清楚眼外伤患者的眼压会有怎样的变化。
