Puncturing blood vessels - elasticity?

[kidaz]

TL;DR

I'm a doctor. How can we predict which needle punctures a vessel?

Hi all! :)

I'm a physician who regularly punctures blood vessels with needles. This is successful when the needle punctures the superficial surface to enter the lumen, but does not puncture the deep surface. If this happens, nearby structures (lung, nerves, heart) are damaged. Increasing force will guarantee a puncture, but not a successful puncture by this definition.

We can modify only a few things: Force, incident angle, needle size, intravascular pressure (via hydrating the patient).
We cannot modify vessel elasticity, vessel diameter (only slightly varies with hydration)

I want to understand in what proportions these modifiable factors make this successful, and what physical laws govern this.

Can anyone help?

 

[Baluncore]

Welcome to PF.

Needle entry into the lumen of a vessel will be different to the penetration of an arrow, lance, or an injection deep into muscle.
As I see it, initial penetration will be by the curved knife edge at the diagonal cut point of the needle. The following diagonal wedge will deflect the tissue and so control the presentation of tissue to the needle. When penetrating a vessel parallel with the surface, the orientation of the diagonal will be important in the way the needle pushes the tissue into a mound, then picks up the first vessel surface, and hopefully “threads” itself into the vessel without passing through the far wall, a bit like threading beads, without stitching them to the table cloth.

Start by getting a copy of; “The Science and Engineering of Cutting” 2009, by Tony Atkins;
pub; Elsevier, ISBN; 978-0-7506-8531-3
I quote from page 184,5;
“
Deep penetration of highly deformable soft solids was studied by Shergold and Fleck (2005) in connexion with medical injections into the human body. Experiments show that a sharply pointed punch results in a planar crack formed in mode I. Indenting was modeled as shown in Figure 8-3. For pointed indenters, the incremental work of penetration performs work of incremental plane crack advance plus the sideways incremental elastic compression of the material which occurs as the shank of the tool displaces material from the core of the hole. The penetration pressure is greater for greater material toughness, greater elastic shear modulus and greater non-linearity; it increases as the punch radius decreases.
Shergold, A., & Fleck, N. A. (2005). Experimental investigation into the deep penetration of soft solids by sharp and blunt punches, with application to the piercing of skin. ASME Journal of Biomechanical
Engineering, 1–41.
”
http://www-mech.eng.cam.ac.uk/profiles/fleck/papers/190.pdf

 

[berkeman]

Summary:: I'm a doctor. How can we predict which needle punctures a vessel?

I'm a physician who regularly punctures blood vessels with needles. This is successful when the needle punctures the superficial surface to enter the lumen, but does not puncture the deep surface. If this happens, nearby structures (lung, nerves, heart) are damaged.

Welcome to PhysicsForums, doctor. Are you talking about starting IVs or some other situation? I don't see how IV access would endanger the lungs or heart, so I may be misunderstanding your question.

Lumen anatomy from wikipedia: https://en.wikipedia.org/wiki/Artery

 

[sysprog]

We can modify only a few things: Force, incident angle, needle size, intravascular pressure (via hydrating the patient).
We cannot modify vessel elasticity, vessel diameter (only slightly varies with hydration)

You can also modify the derivatives of position wrt time (velocity (1st), acceleration (2nd), jerk (3rd), snap or jounce (4th)) and their inverses in making sure that you don't overshoot.