Spread of fluid: Role of tip configurations in needles

Background/purpose: During the injection of a fluid in a tissue model, the fluid might be affected by the needle tip configuration and the number of channels. Thus, the objective of the present work is to observe the influence of different needle tips and number of channels on the spread of a fluid. Methods: Fluid distribution data were obtained after injecting 0.3mL of fluid into a foamed polymer model with a velocity of 2mm/s. The spread area and the depth were determined for 3 different types of hypodermic needles: Single channel needles with bevel tip and blunt tip and a needle with conical tip and 3 internal channels. Results: The bevel tip provides a higher spread in the direction where the bevel points and reaches larger depths than the other two needles. The spread for the blunt tip and the polymer needle is equally distributed on both sides of the needle. The largest horizontal area around the tip is achieved by the 3-channel needle. Conclusion: The tip configuration and number of channels have an influence on the distribution of fluid. The bevelled needle directs the fluid and reaches larger depths compared with the 3-channel needle that gets more horizontal spread.