Advantages of Larger Syringe Barrels for Aspiration & Pathology Removal

[Syringe User]

We need to figure out the advantage, if any, of using a larger diameter barrel syringe to aspirate fluid and pathology (cells, blood clot & tissue) from a patient using identical size catheters or needles.

Lets ignore that, all things equal, it takes more force to pull back a larger plunger for the momement. The below will be using identical 100cm catheters with 1.5mm inner lumens.

1. What will the aspiration difference be between a syringe barrel with a 29mm and a 40mm diameter if each have an identical 40mm stroke (plunger travel)?
2. Will the larger barrel pull liquids or solids faster through a catheter if connected to a catheter and the plunger is pulled back once?
3. Consider that we can put an automatic three-way valve on the tip of the syringe. The valve will open to suction from a catheter when the plunger is pulled back to aspirate, then the valve will automatically close to the catheter and open to a drain bag to eject the fluid/pathology in the barrel when the plunger is pushed back in. A user can then pulse the plunger open and closed to pull aspiration/drain. Given this 3-way valve, will a 29mm or a 40mm barrel give more suction-aspiration force?

We know of a new syringe design that allows physicians to pull negative pressure easier than before and are tying to hypothesis the benefits of it's use in aspiration biopsy and thrombus removal. For example, if the plunger is all the way pushed in on the 40mm diameter syringe and the tip is sealed, I cannot pull the plunger back with two hands using a traditional syringe design. But, with this new design, a child can pull back the plunger with one-hand on the 40mm diameter design. Knowing that we max out at 1atm of vacuum, what will the advantage be besides more volume. Can we get more aspiration, suction or negative pressure force?

 

[Baluncore]

There will be an advantage only on the first aspiration while the air in the catheter lumen is being replaced by sample fluid. That advantage will be minor as air is much easier to draw than a liquid. The rate will be quite independent of the syringe diameter once the lumen is filled with sample fluid. That is because the atmospheric pressure limit is independent of syringe diameter, so the suction force moving fluid along the catheter is constant.