Effect of Back-Cut Point Needle Bevel Angle on Deterioration After Multiple Punctures in Central Vein Simulation.

Background: Multiple needle punctures during central venous line insertion can lead to serious complications. Needle deterioration owing to repeated punctures may be a major cause. We hypothesized that there is an optimal bevel angle for a back-cut point needle that is resistant to deterioration. In this study, we examined the effect of bevel angle differences in a back-cut point needle on needle tip deterioration caused by multiple punctures.

Methods: The resin target was punctured perpendicularly using back-cut point needles with three bevel angles (15°, 17°, and 19°; n=8 for each angle) at a speed of 200 mm/min. The same needle was used for ten consecutive punctures at different locations on the target. The force applied to the needle was recorded as puncture force. The puncture force waveform is bimodal. The second peak values, which formed the maximum values of puncture force, were the focus of the main analysis. We considered a 5% elevation from the first to the 10th puncture force as needle deterioration, and the average slope value of the regression line between the puncture number and puncture force was used. When the upper limit of the 95% confidence interval (CI) of the slope value was less than 0.008889, the needle was considered to be resistant to deterioration.

Results: The slopes of the second peak values during 10 consecutive punctures for each bevel angle (15°, 17°, 19°) were 0.003011 ± 0.01085 [-0.006056, 0.012077], 0.006116±0.007431 [-0.000096, 0.012328], and 0.001515 ± 0.005783 [-0.003320, 0.006349], respectively (mean ± standard deviation [95% CI]). Only the 19° angle needle had a smaller upper limit of the 95% CI for a slope value of 0.008889.

Conclusion: The 19° bevel angle back-cut point needle was more resistant to deterioration than the 15° and 17° angle needles were.