Laboratory Study on Needle–tissue Interaction: Towards the Development of an Instrument for Automatic Venipuncture

Abstract

Although venipuncture is one of the most common clinical procedures and is performed by trained medical staff, difficulties arise in 5% of insertion procedures. An instrument that guarantees the insertion of a needle into a vein in a single approach is expected to be beneficial to both medical staff and patients. The next step towards automatic venipuncture is to determine if insertion force feedback can be used, irrespective of insertion speed, insertion angle, or vein depth and diameter. Needle insertion experiments are performed on phantom and porcine tissues to study the interaction between the needle and tissue. A prototype instrument is developed to perform automatic venipuncture on the phantom. From the experiments, we conclude that an increased insertion speed of the needle leads to an increase in insertion force and tissue deformation. Furthermore, distinct force peaks are observed at the penetration of phantom skin and vein, thus enabling automatic detection of phantom vein puncture.

Modelling Framework and Assistive Device for Peripheral Intravenous Injections

“…The assumed final resting angle of the needle with respect to the surface of the injection site 15 of this final motion is indicated by θ f and the total length of the needle inside the patient's tissues is (l0 + l 1) , where l 1 is the additional length of the needle that has been inserted during steps 3 and 4. If l 2 represents the length of the part of the needle outside the injection site 10, then the total length L of the needle satisfies the relation…”

“…the needle is rapidly inserted into the injection site at an initial velocity v 0 , whereby it slows down somewhat when the tip of the needle passes the first vein wall at about t = t 0 . After that, the velocity profile must decrease with time (or equivalently with the depth of penetration), so that the needle motion in path P 34 must eventually come to a halt at the desired depth of penetration of (l0 + l 1) , at time t = t f . This profile can be approximated by quadratic or higher polynomial functions, or numerical representations if necessary.…”

“…blood sampling, with an estimated 3.5 million being performed worldwide each day [1]. These procedures are often unpleasant and require skill and dexterity, delivered confidently in a smooth VP action on a steady site.…”

“…Failed attempts in venous access via these procedures are unfortunately common, due mostly to difficulty in seeing [2] or accessing the target vein [3], or as a result of inexperience or nervous phlebotomy practitioner. De Boer et al [1] estimate that there are difficulties with as many as one in twenty procedures. A successful VP process (i.e.…”

“…[4][5][6][7], much of the associated modelling has been applied to needle injections into deep central tissues such as liver [8,9], often assisted by ultrasound [10] or computed tomography [11], rather than to the peripheral VP process. De Boer et al [1] have developed an instrument for automated VP and analysed the forces produced in phantom and animal tissues. However their device inserted the needle in a straight-line path rather than the more subtle non-linear trajectory employed in actual clinical practice.…”