May 28, 2021

aspirating needle botox fillersIn this article we will continue to learn how to raise the bar and thrive in the world of aesthetics with detailed insights on one of the most controversial topics, Aspiration! Does it work?

Aspiration is the safety step a lot of aesthetic healthcare practitioners use to avoid the risk of an intravascular injection when treating patients with dermal fillers. It follows the same logic as a screening test, which is you’re basically taking an extra measure to try and weed out whether or not you are in a blood vessel.

The theory is if you’ve got the tip of your instrument, be it needle or cannula inside a blood vessel, and you pull back the syringe, hopefully you get blood back in the syringe thus indicating if you’re in a vessel. Although the probability of these vascular incidents can be considered low (estimated between 1:2000-1:10,000, when one of these vascular occlusions happens, it can be devastating to the patient if not dealt with urgently.

Is it worth aspirating?

non surgical treatment injectionsTo aspirate or not, that is the question!

To answer our dilemma, we must remember that we have made a commitment to provide safer treatments for our patients.

Dr Tim comments:

“Even if we are avoiding that ‘one in a million case’ that can go wrong, we have seen first-hand more than 120 positive aspirations in our clinic, which we believe did prevent dermal complications, and so I believe all practitioners should make aspirating part of their daily practice.”

So YES, Dr. Pearce considers this step important and worth spending a bit more time in every dermal filler appointment you carry out. However, we first have to learn how to do it successfully to get less and less false positives and negatives.

How to aspirate

We certainly suggest you start by finding a good technique of positioning yourselves. Dr Tim always instructs the doctors he trains to be accurate and to keep their stability while injecting. Did you know that an aspiration can be made pointless if you stray as little as 3mm from the point where you made the “safety check”? We suggest you apply the tips shared in the Aesthetics Show below:

The other elephant in the room we need to address involves physics. We have to understand the factors that affect aspiration sensitivity. Luckily, the flow of fluids (Poiseuille’s Law) provides us with the knowledge to understand the range in dermal filler density which will affect the success of aspiration. Aspirating simply isn’t possible with some thick fillers, while some that are too high in viscosity can take more seconds to draw blood in the syringe. Pressure difference and the radius of the tube are proportional with the flow rate, while the length of the tube and the viscosity are disproportional.

It’s possible to examine the fillers we will use by conducting some straightforward tests. In the link below you can see an aspiration experiment Dr Tim Pearce conducted to compare dermal filler brands to see how long they take to aspirate (or if they aspirate at all). The test is made with different fillers being injected by Dr Tim into his own arm!

Aspiration test results

Dr Tim aspirationThe results of the test are available here for each dermal filler brand tested at Aspirating Experiment Test Results: How Quickly Does Your Filler Brand Aspirate…If At All?.

We also need to mention the size of the needle. 4mm ones make aspirating insignificant, that is why many aesthetic practitioners suggest using longer ones to remain secure from the threat of touching any superficial branch of the artery. While with longer ones, we have to keep in mind that sometimes there is a need for more time to create the negative pressure.

Another important thing to keep in mind and to practice is that we have to learn an efficient way to have a neutral force vector while aspirating. Find out more in this video:

What to do when we aspirate blood?

Dr. Tim says:

“I feel great when I get a positive aspirate, I feel like all that aspirating I have been doing has finally paid off, and otherwise today could have gone horrifically wrong. So instead of a patient lying on the bed for two hours and worrying about her face while I try and reverse a vascular occlusion, all I have is a syringe full of blood. So I’d much rather have that, than the other experience.”

During the consent process, after you explain the possible complications, Dr Tim recommends you tell your patients that you have a step that can significantly lower the probability of such a complication from happening i.e. aspirating. You reassure them in case something like this happens and they see blood in the syringe. They will feel happy having chosen you and knowing that you made their aesthetic journey safer.

Don’t forget that when you aspirate blood, usually the amount it enters is moderate, so you just have to remove that part of the filler mixed with blood and change the needle. So the cost should not be something to alarm you. There are indeed only a few cases where the blood blends in one mass with the filler. We don’t recommend using the syringe in such a case because it would be like injecting a hematoma, and furthermore, you can’t detect the future aspiration results.

Is there an exception?

So there are places where it seems really clear that you’re unlikely to get a big aspiration result from a vessel, like treating fine lines. When you can see the shape of the needle, there are certain parts of the face where you can literally see the skin kind of drop off the end of the needle. When you lift it slightly, you can tell you’re not on a major vessel.

Does a cannula avoid complications more?

Cannulas have proven to be more effective in decreasing the number of complications, but we do recommend aspirating, considering that with cannulas the injuries can be more severe and harder to treat if the injection was made in a blood vessel.


Was this article a calling for you towards trying aspiration? Does aspirating work according to you?

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Useful Links

Further reading about dermal filler complications

You may find the following articles useful:

Still anxious about delivering cosmetic injectables safely?

If you want to learn more about mastering medical aesthetic treatments and complications, or conquering the anxiety of where to place your needle, then register for the next Dr Tim webinar.

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Dr Tim Pearce eLearning

Dr Tim Pearce MBChB BSc (Hons) MRCGP founded his eLearning concept in 2016 in order to provide readily accessible BOTOX® and dermal filler online courses for fellow Medical Aesthetics practitioners. His objective was to raise standards within the industry – a principle which remains just as relevant today.

Our exclusive video-led courses are designed to build confidence, knowledge and technique at every stage, working from foundation level to advanced treatments and management of complications.

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