Differences in Penetration Force of Intravenous Catheters: Effect of Grinding Methods on Inner Needles of Intravenous Catheters

摘要

Objectives: To compare penetration forces of intravenous catheters based on two grinding methods used for the inner needle tip. Method: Forty intravenous catheters were divided into two groups according to two inner needle grinding methods: Lancet and Backcut. To compare the characteristics of inner needles, 18 gauge Surflo~® outer catheters, were attached to all inner needles. We measured penetration forces by attaching a "Push-Pull-Gauge" to the chamber of intravenous catheters, then we penetrated intravenous catheters through a 0.04-mm thick polyethylene film. The penetration velocity was 3.3 mm/sec, we measured penetration forces at 30- and 45-degree penetration angles. Results: There was no significant difference in the penetration forces of inner needle and outer catheter between the two groups at the 45-degree penetration angle. Penetration forces of the inner needle and the outer catheter in the Backcut group was significantly lower than those of the Lancet group at the 30-degree penetration angle. The penetration force of the outer catheter was reduced from 0.3 N to 0.18 N, a 40 % reduction at 30-degree penetration angle. Computerized measurements of penetration holes indicate that the Y-shaped incision mark of the Backcut leaves larger incision hole than the actual puncture size. We hypothesize that the Y-shaped incision mark creates more efficient path for the outer catheter to advance. Therefore, lower penetration force was indicated compared to the other group. Conclusion: Backcut shows less penetration force of inner needles of peripheral intravenous catheters than lancet.