Another wee drip

[fergus]

I'm wondering how many other insulin users find this problem.

Sometimes, when using an insulin pen, it delivers a stream of insulin and doesn't leave any residual fluid hanging on the end of the needle. At other times, the insulin is deivered as a series of drops, and a wee drip remains on the needle even after it is withdrawn.

Changing the needle makes no difference to this and so I'm thinking it might have more to do with the vial, perhaps the volume of air relative to insulin.

The problem is, if you are using a small dose, a wee drip can be a large percentage of it.

Anyone else struggle with this?

All the best,

fergus

 

[sixfoot]

im a T2 and use BYETTA injector pen with fine 8mm needle 31g, i find this sometimes happens as well.

Dave P

 

[Jay3109]

Don't know why it happens, but it always does. I think this is why we are always told to leave the needle in place for at least 8 to 10 seconds after 'plunging' to ensure you get your full dose. The bit on the end may just be a bit extra, though I get your point about small doses!! :shock:

 

[totsy]

it always happens to me, i inject and count to 10,when i remove it always drips :?

 

[lilibet]

Me too! I leave it under skin for count of 20 but often still drips. I too worry about not getting full dose but more worried about the drips causing reactive dermatitis on my arms. That and the bruising

Ah, the joys

L

 

[Dennis]

Like Dave, I often find find a drip on the end of my Byetta pen needle, but the Byetta dose is quite substantial so one small drop is probably a lot less significant than it is for an insulin user.

 

[timo2]

Hi Fergus,

I definitely don't think that having air bubbles in the vial helps. Using finer gauge needles
can also exaggerate the problem.

Like lilibet, I usually give my needle a good 20 seconds under the skin. If I still get drips
after doing this, then I think it's normally down to my having picked a lumpy spot to inject,
rather than the fault of the pen.

Best regards,
timo.

 

[fergus]

Ah, so it's not just me then?

The odd thing is that at certain times, the flow from the needle is good and no droplets appear after priming the pen, or injecting. Then at others I get a sequence of drips. It doesn't matter how long I leave the needle in place, it seems there is insufficient pressure in the system to deliver the full dose and drops appear when the needle is withdrawn.

On a small dose of 2 or 3 units, this could be as much as half the dose!!!!!

Disposable syringes were more reliable than that!!!!

All the best, fellow drippers

fergus

 

[suzi]

When we were mere novices Andrew and i often had drips, so DN gave us a half unit pen, which worked wonders at first, half unit may seem so small but you'd be surprised the difference it can make. Only draw back was when increasing from small units to larger ones, to inject 20u means 40 clicks! So now we only use it during school at lunchtime for tighter control when doing carb counting using humalog, ie 7 1/2u.
Have found pens that take cartridges tend to drip more and get more air bubbles, haven't really noticed it in the disposable pens. Anyway thats our experiences, and i suppose at the end of the day it could all be down to techniqe.
Suzi x

 

[phoenix]

When on MDI I noticed a drip but it was a tiny drip and consisitant so I didn't consider it was important (since the drip size always seemed bout the same). I used disposable pens and a new needle each time.(my doses ranged from 3 to 7 on a big meal)

 

[fergus]

Thanks everyone.

I think I've figured it out now. I replaced my humalog vial this morning. The new vial has an imperceptably small volume of air inside it. Therefore, all the pressure applied by the plunger will result in the displacement of insulin through the needle in a continuous stream, due to the release of pressure. Sure enough, a nice strong stream when I primed the pen, and an insignificant droplet left behind afterwards.

The old vial has a significant air bubble within it. There are around 30 units of humalog still in there and at a rough guess, around a quarter of that volume is nothing but air. So, the pressure applied by the plunger will partly just be applying pressure to the air (more easily compressed) rather than the liquid. When the dose is delivered, the air pressure will be released, resulting in a lower actual dose of insulin, and a drop in pressure which will cause the insulin to drip, rather than stream. There will be insufficient pressure to deliver the full dose under the skin, so that when the pen is removed, this low-pressure insulin will slowly emerge as droplets rather than a stream.

At least this is going to explain my slightly higher than normal bg over the past 2 days. Always easier to blame the technology than blame myself. :shock:

All the best,

fergus

 

[fergus]

D'oh!

An obvious solution, and H. Simpson award of the week for me for not realising it sooner.

Prime the pen when it is pointing directly upward. That way, all of the air in the vial can be expelled. After that, the next dose will be delivered as a strong stream and little or no insulin left on the end of the needle afterwards. Anyone brought up with disposable syringes, like me, ought to remember that's what we used to do. Since being on a pen I'd simply forgotten.

All the best,

fergus

 

[Dennis]

Thanks for that Fergus. My Byetta pen instructions say to prime it pointing upwards. It never occurred to me that there was a logic behind this - until you pointed out the obvious! Make that 2 HS awards!

 

[sugarless sue]

Hold upwards,flick to get air to the top,press plunger gently to expel air.Same as a syringe then? I've never used a pen so didn't realise how you use it etc.