Department of Anesthesiology and Critical Care Medicine, Oita University Faculty of Medicine, Oita, Japan.
Korean J Anesthesiol. 2012 Jul;63(1):59-64. doi: 10.4097/kjae.2012.63.1.59. Epub 2012 Jul 24.
Ultrasound subjective visibility of in-plane needles is correlated with the intensity difference between the needle surface and the background. Regional anesthesia catheters are difficult to visualize by an ultrasound. In the present study, we investigated the ultrasound visibility of the catheters.
Six catheters were placed at 0° and 30° relative to and at a depth of 1 cm below the pork phantom surface. Ultrasound images of in-plane catheters were evaluated, subjectively and objectively. Outer and inner objective visibilities were defined as the difference in the mean pixel intensity between the catheter surface and adjacent background, and between the surface and the center of the catheter, respectively. Evaluations were made based on the portion of the catheters. A P value < 0.05 was considered significant.
Subjective visibility was more strongly correlated with the inner objective visibility than with the outer objective visibility at both angles. Metallic 19-gauge catheters were more subjectively visible than the non-metallic 20-gauge catheters at 30° degrees (P < 0.01). Subjective, and outer and inner objective visibility were significantly lower at 30° than at 0° (P < 0.01, P < 0.01, P = 0.02). Perifix ONE at 0° and Perifix FX at 30° were the most visible catheters (P < 0.01 for both).
Subjective visibility of catheters can not be evaluated in the same manner as that of the needles. For the best possible visualization, we recommend selecting a catheter with a structure that enhances the dark at the center of catheter, rather than basing the catheter selection on the bore size.
平面内针的超声可见度与针表面和背景之间的强度差相关。区域麻醉导管在超声下难以可视化。在本研究中，我们研究了导管的超声可见度。
将 6 根导管分别以 0°和 30°的角度和 1cm 的深度放置在猪模型表面下。对平面内导管的超声图像进行了主观和客观评估。分别定义外客观可见度和内客观可见度为导管表面和相邻背景之间以及表面和导管中心之间的平均像素强度差。根据导管的部分进行评估。P 值<0.05 被认为具有统计学意义。
在两个角度下，主观可见度与内客观可见度的相关性均强于与外客观可见度的相关性。在 30°时，金属 19 号导管比非金属 20 号导管更具主观可见性（P<0.01）。在 30°时，主观可见度、外客观可见度和内客观可见度均明显低于 0°（P<0.01、P<0.01、P=0.02）。在 0°时的 Perifix ONE 和在 30°时的 Perifix FX 是最可见的导管（两者均 P<0.01）。
导管的主观可见度不能像针一样进行评估。为了实现最佳可视化，我们建议选择具有增强导管中心暗度结构的导管，而不是基于导管内径大小进行选择。
