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Enhanced needle visibility by microbubbles generated with negative pressure using an in-plane technique
  1. Yong Liu,
  2. Xingxing Sun,
  3. Wei Qian,
  4. Wantao Liu and
  5. Wei Mei
  1. Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
  1. Correspondence to Dr Wei Mei, Departement of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; wmei{at}


Background and objectives Our previous work found that needle visibility could be improved by introducing microbubbles into needles. The primary aim of this study was to test the hypothesis that the negative pressure method is superior to two other methods for enhancing needle visibility by introducing microbubbles into needles. The secondary aim was to evaluate the impacts of three factors on the visibility of microbubble-filled needles.

Methods In the first phase, three methods, including the negative pressure method, the mixing method and commercialized microbubbles, were applied to generate microbubbles inside needles for comparison of visibility in a porcine meat model. In the second phase, three factors were tested with a 2×5×5 factorial design to explore their influence on the visibility of microbubble-filled needles. The three factors included types of needles, insertion angles and types of contents inside needles. Needles filled with saline without microbubbles were used as the control in both phases. Insertion videos were recorded, and ultrasound images of needles were captured for the objective visibility analysis.

Results Needle visibility was highest in the negative pressure method group (p<0.001). Needle visibility was mainly determined by insertion angles (p<0.001). Microbubble-filled needles were more visible than control needles at 40°, 50° and 60° (p<0.001, p<0.001 and p<0.001, respectively).

Conclusions Needle visibility can be significantly improved by microbubbles generated with the negative pressure method when insertion angles are 40°, 50° and 60° in porcine meat.

  • regional anesthesia
  • technology
  • resident education

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  • YL and XS contributed equally.

  • Contributors Conception or design of the work: WM, YL and XXS. Conduct of the study: YL and XXS. Data collection: YL and XXS. Data analysis: WQ, WTL, WM and YL. Drafting of the article: YL and WM.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The institutional review board waived the need for ethics approval for this nonclinical study.

  • Provenance and peer review Not commissioned; externally peer reviewed.