Purpose A solution for real-time, ultrasound-guided, central neuraxial blockade placement remains elusive. A device that enables single-operator neuraxial placement while simultaneously visualising the spinal anatomy and needle trajectory may improve patient safety. We engineered a novel needle guide, the EpiGuide two dimensional (2D), and compared prepuncture insertion sites as located using the guide versus standard manual palpation.
Methods Interdisciplinary collaboration between engineers and obstetric anaesthesiologists and multiple iterative refinement led to the EpiGuide 2D, a prototype multichannel needle guide for ultrasound transducers. Following ethics committee approval, 22 healthy adult participants were recruited to undergo prepuncture lumbar epidural placement using the guide. The primary outcome was accuracy, defined as the percentage of successful placements of prepuncture needle insertion sites within the manually palpated intervertebral space. The secondary outcome was distance between the prepuncture insertion sites guided by the EpiGuide 2D versus by sites guided by manually palpation.
Results Mean (SD) body mass index of participants was 22.6 (2.1) kg/m2. The success rate of selecting a prepuncture site within the manually palpated intervertebral space using EpiGuide 2D was 95.5% (42 of 44 attempts). Of the failed sites, the mean (SD) distance to the intervertebral space was 1.3 (0.3) mm in the caudal direction. The mean (SD) distance between EpiGuide 2D sites and palpated sites was 3.6 (2.0) mm.
Conclusion The EpiGuide 2D, jointly developed between engineers and anaesthesiologists, was found to be as accurate as manual palpation in placing a prepuncture site within the intervertebral space.
- neuraxial blockade
- needle guide
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Contributors RR originally conceived the idea for the EpiGuide. RR and PA were coinvestigators for funding. RS, CB, SH, AC and RR were responsible for prototype design. SH and RS were responsible for prototype development. CB and RS were responsible for participant recruitment and study execution. RS performed data analysis. All authors contributed to the writing of the manuscript and providing feedback throughout the process. RR was the overall project principal investigator.
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 The authors declare that a US provisional patent (No. 62/666,260) has been submitted for this work. The authors declare no conflicts of interest.
Patient consent for publication Not required.
Ethics approval The study was approved by the University of British Columbia Research Ethics Board (H15-01310).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request.
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