Schwemmer U, Geppert T, Steinfeldt T, Wunder C
Klinik für Anaesthesiologie und Intensivmedizin, Klinikum Neumarkt, Kliniken des Landkreises Neumarkt i.d.OPf., Nürnberger Str. 12, 92318, Neumarkt i.d.OPf., Deutschland.
Klinik für innere Medizin, SLK Klinikum am Plattenwald, Bad Friedrichshall, Deutschland.
Anaesthesist. 2015 Dec;64(12):937-942. doi: 10.1007/s00101-015-0098-3. Epub 2015 Oct 13.
In the context of ultrasound-guided peripheral nerve blocks (regional anesthesia), clear visualization of the needle tip and the target structure are mandatory for the performance of a safe puncture and injection. The purpose of this in vitro study was to analyze the visualization of different forms of needle tips and calibers of cannulas in a phantom simulating human tissue, with the help of a standardized image analysis system. Different depths and angles of the puncture needle in relation to the ultrasound probe were tested.
Cannula needles established for use in regional anesthesia with different surfaces, diameters and needle tip form in 23 different combinations were analyzed. A gelatine-based phantom was used to simulate human tissue. The standardized visualization of the needle tip with the ultrasound probe was performed in plane at different angles (30°, 45° and 60°), depths of penetration (1 cm, 2 cm and 3 cm) and two different alignments of the cannula needle lumen to the ultrasound probe (0° and 180°). The screenshots of the ultrasound pictures were analyzed by quantifying the pixel brightness around the needle tip (region of interest) with a standardized software (score 0-255).
In this study 1104 ultrasound images of cannula needles were analyzed. Diminished scores (reduced pixel brightness) of the needle tips were documented with increasing distance from the ultrasound probe. Comparison of punctures at angles of 30° and 45° showed no differences in needle tip visibility (same scores) but punctures at an angle of 60° were poorly visualized compared with 30° and 45° (mean scores 87.90 ± 11.60 vs. 78.40 ± 12.07, p < 0.001 and 81.85 ± 11.79 vs. 78.40 ± 12.07, p < 0.001, respectively). The direct alignment of the cannula lumen towards the ultrasound probe (0°) was significantly more easily visualized when compared with the reverse alignment of 180° (mean scores 86.90 ± 12.74 vs. 84.80 ± 11.66, p = 0.003, respectively). No differences in visibility were detected between the different cannula needle diameters examined. The Sprotte cannula showed the best visibility score with respect to the cut of the needle tip (mean score 89.40 ± 11.72).
The visibility of cannulas in ultrasound scans depends on the ultrasound frequency, angle of the puncture in relation to the ultrasound probe and the depth of penetration. The results of this study showed that direct alignment of the cannula needle lumen towards the ultrasound probe (0°) independently improved needle tip visualization. This simple measure allows a significant improvement in the safe performance of ultrasound-guided peripheral nerve blocks.
在超声引导下的周围神经阻滞（区域麻醉）中，为了安全地进行穿刺和注射，必须清晰地看到针尖和目标结构。本体外研究的目的是借助标准化图像分析系统，分析在模拟人体组织的模型中不同形式的针尖和套管口径的可视性。测试了穿刺针相对于超声探头的不同深度和角度。
分析了用于区域麻醉的套管针，这些套管针具有23种不同组合的不同表面、直径和针尖形式。使用基于明胶的模型模拟人体组织。在平面上以不同角度（30°、45°和60°）、穿刺深度（1厘米、2厘米和3厘米）以及套管针内腔与超声探头的两种不同对齐方式（0°和180°），用超声探头对针尖进行标准化可视化。通过使用标准化软件（评分0 - 255）对针尖周围（感兴趣区域）的像素亮度进行量化，来分析超声图像的截图。
在本研究中，分析了1104张套管针的超声图像。记录到随着与超声探头距离的增加，针尖的评分降低（像素亮度降低）。30°和45°角度穿刺的针尖可视性比较无差异（评分相同），但60°角度穿刺与30°和45°相比可视性较差（平均评分分别为87.90±11.60对78.40±12.07，p < 0.001；81.85±11.79对78.40±12.07，p < 0.001）。与180°的反向对齐相比，套管内腔直接朝向超声探头（0°）的对齐方式明显更容易可视化（平均评分分别为86.90±12.74对84.80±11.66，p = 0.003）。在所检查的不同套管针直径之间未检测到可视性差异。就针尖的切面而言，Sprotte套管显示出最佳的可视性评分（平均评分89.40±11.72）。
超声扫描中套管的可视性取决于超声频率、穿刺相对于超声探头的角度以及穿刺深度。本研究结果表明，套管针内腔直接朝向超声探头（0°）的对齐方式可独立改善针尖的可视化。这一简单措施可显著提高超声引导下周围神经阻滞的安全性。
