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PostPosted: Fri Jun 26, 2015 12:52 pm 
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I have considered this dilemma with some forgetfulness and consternation over the years of giving IVs to horses. The books and schools teach always insert the needle bevel-up, but no good reasons have really ever been given for this dogma of a technique. From my own experience of doing this for 30+ years and doing a casual research online of human IV technique, I have come to the conclusion it probably doesn't matter! There are indeed many roads to Rome and whether you insert the IV needle with bevel up or down, there is no good reason for not doing it either way.

Personally, I do lean to inserting the needle with bevel down, but I have equally been known to do it with bevel up if I don't have initial success. The basic key to hitting the jugular the first time is to see and feel the vein first before inserting the needle. Since the jugular vein lays near or under the jugular groove in the neck, the groove is the first topical landmark you look for to find the vein. I cannot over emphasize this too much! You must see the jugular vein underneath the skin to know where to puncture it! On a thick hair coat or a young animal, this will be harder. Clip hair if possible and wet with antiseptic alcohol. This will allow you to see the vein better and also help with aseptic technique. There will also be less hair to contaminate the needle on its way in! Bending the neck slightly to the opposite side (if giving in left jugular, bend to right) may help see the jugular better, too. Next, take your free hand and apply pressure caudal (toward the tail) to insertion site and this will result in the vein ballooning a bit--rising the skin up. It will also help if you apply intermittent pressures at this lower site to better visualize where the jugular is. You will see the jugular balloon up and down when depressing and releasing your posterior finger pressures. Also, the jugular is mostly found in what is known as the jugular groove or furrow on the neck as seen in this photo:



Attachment:
jugular furrow.png






Some reasons casually thrown around for either technique:

1) with bevel up, the sharp edge pieces the skin first resulting in less pain & tissue trauma,
2) entering with bevel down causes painful skin tearing,
3) bevel up approach is for ease of flow. Because the needle enters at an angle, if the bevel were down it sucks up the back wall of the vein, restricting flow,


Some favorable ideas to going bevel down:

1) In small and/or dehydrated veins, it may be superior,
2) less likely to pierce the opposite vein wall by making the angle of insertion more shallow,
3) the bevel will be approximately parallel with the opposite wall,
4) bevel down leaves a skin flap down that actually heals faster than the flap up which the bevel up leaves. Some nurses have reported that the bevel down technique bleeds less,
5) entering the vein (at any angle) with the bevel down instead of up vastly increases the area of the bevel that gets into the lumen,


In the end, it will be those that are first taught how to insert the needle and who have been comfortable with this technique to be convinced their way is the best way. So be it. Certainly do it in a way which gives you the most success and comfort! However, either way will work. Personally, I generally prefer the bevel-down position because:

1) Since hair on the coat tends to point downwards, I feel like there is less chance that the needle will scoop up hair with the bevel down. Less of a "spoon" type of effect.

2) I see no credence in the idea that the sharp end of the needle will hit the skin first if the bevel is up. This would only happen if you are basically touching the hide at a very low angle which to me is never advisable as it will cause you to miss the vein entirely by going just under the skin, plus it will allow for more chances of contamination with skin at such a low angle.

3) I also subscribe to the idea that there is less chance of puncturing the opposite wall of the jugular when the bevel is down. There also may be a slight danger of actually going through the jugular into the underlying carotid artery which lays just underneath the jugular vein, if the bevel is inserted upwards:


Attachment:
Bevel-Down_260.jpg





Attachment:
angle1.jpg





With this last drawing, I think the basic mechanics can be seen. With the bevel-up, you are creating a higher angle of needle insertion than you would if inserted with the bevel-down position. That in itself could have some practical applications for preventing a misplaced injection into the carotid artery.


Attachment:
iv angles.jpg


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PostPosted: Fri Jun 26, 2015 12:55 pm 
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On a related note, you may have seen some so-called LED vein finders out there on the market. They mostly consist of an array of LED red lights designed to be placed on the skin to illuminate underlying veins. Well, in theory any way! I decided to buy one and found they do an acceptable job on human skin, but not so much on animals with a hair coat. So, if you are interested in buying one for vet use, I doubt you will be happy.



Attachment:
veinfinder1.jpg



or the really cheap version:



Attachment:
veinfinder2.png


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