I am an student and we learned this semester that you NEVER aspirate, with any kind of injection. They didn't tell us why, but from what I've gathered from an internet search is that there's no evidence supporting the technique, so it's not necessary. For IM injections, the needle will bust through any capillaries, and with use of proper landmarks, you will not hit a vein. Also, maybe it's safer for the nurse because there's less possible exposure to the patient's blood? I briefly searched for an article on the subject that I could refer you to, but couldn't find anything. If you do find a definitive answer, post it here
I graduated in 2010 with my ADN and am finishing up my bachelor's in nursing this December. We were taught in both to aspirate. However, I did find the following reasoning behind not aspirating interesting:
Aspiration of the syringe plunger once the needle has been inserted into the muscle is an accepted part of IMI procedure but there is no evidence of the need to do this. Justification includes to ensure the drug does not enter the capillaries (Hunter, 2008) or to avoid inadvertent IV administration (Workman, 1999).
Aspiration may be relevant to detect possible penetration of gluteal artery when the dorsogluteal muscle is used - this would indicate incorrect initial land-marking. However, official guidance (DH, 2006; WHO, 2004) does not recommend routine use of the dorsogluteal muscle, and this should be sufficient to justify changing practice. If this site were removed from routine practice, aspiration could be removed from the procedure, simplifying it and reducing the risk of adverse events. Pharmaceutical developments including reduced volume and less caustic injectates, along with prescribing changes, now support its removal from selected injection sites.
Some auto-disable devices (syringes where the needle retracts automatically after IMI administration to prevent needle-stick injuries) are triggered by the 'aspiration' type manoeuvre, so the technique has already changed in many countries.
Malkin, B. (2008). Are techniques used for intramuscular injection based on research evidence? This article debates the evidence surrounding the nursing procedure of administering intramuscular injections. Nursing Times, 104(50-51), 48-51. Retrieved from EBSCOhost.
I am currently a student in an ADN program, and was taught to aspirate on every IM injection. If I remember correctly, the reason that the instructors gave was because of the possibility of accidently hitting a blood vessel and actually injecting IV instead of IM. From the research on line, though, I haven't found much support for aspirating with IM. But, since I'm in school, if my instructor says to aspirate, I'll aspirate!
Plus, one of the instructors became an RN in 1976 and she was originally taught to aspirate a subcut injection, so go figure!
From what I've read, recent evidence seems to suggest that there is little benefit. You can have it in a blood vessel and it won't aspirate blood, and you might not have it in and get blood. As a previous poster reported, it seems it could only be good for dorsoglut
Thanks for sharing the info about aspirating It's interesting that instructors are now teaching to not aspirate. I was taught to always aspirate, but that was about 12 years ago. It makes sense that if you do it in the right spot, it is unlikely to hit a vessel. As a matter of fact, I don't ever recall aspirating any blood when IM injections. I actually was more worried about manipulating the needle while I was pulling back on the syringe. The only person I would be cautious about not aspirating is someone who is very, very thin. Some cancer or HIV pts can have close to no muscle mass and that can sometimes be tricky.
Aspirating and then injecting causes more pain than just injecting. There also aren't any major blood vessels in area of the injection sites. That is why it is recommended to not aspirate when giving an IM injection.
I graduated in December 2010; and in my program, they drilled the whole aspirating thing into our heads, so I just did it. It's just habit for me to do it now. I haven't seen anyone else aspirate when giving IM's at my hospital, though. I read there is little to no benefit and as ScottE said, it can cause more pain. I still do it, though.