Danger of injecting IM vaccine into blood vessel?

[bbpiano1]

I know you're supposed to check that you're not in a blood vessel when giving a vaccination, but what exactly is the danger in doing so. Will it cause DIC or something?

Also, anyone know what the pharmacologic difference is b/w IM and SQ shots (ie why can't you use a SQ depot intramuscularly)?

bb

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[agranulocytosis]

I can't answer the 1st question, but the 2nd one deals with molecular weight and optimal absorption. I can't recall which route is used for larger molecular weight substances.

 

[BSN2DOC]

I know you're supposed to check that you're not in a blood vessel when giving a vaccination, but what exactly is the danger in doing so. Will it cause DIC or something?

Also, anyone know what the pharmacologic difference is b/w IM and SQ shots (ie why can't you use a SQ depot intramuscularly)?

bb

When giving an IM injection, it is given in the muscle so that the med is absorbed more slowly rather than pushing it directly into the circulatory system. It also helps control the body's response to the medication -- your body would react different if you were to inject it all at once.

Thus, there usually is not any harm if an IM medication were pushed into a blood vessel (however, from what I understand, pushing a vaccine into a blood vessel can limit the efficacy of the vaccine).

And again, the differences between IM, SQ, IV (pretty basic concept) involves the different levels of absorption. It is medication dependent.

 

[AmoryBlaine]

There is some pretty good nursing literature to suggest that aspirating back on IM injections is not necessary. That said it's an easy thing to do that takes ~1second so I go ahead and do it.

You also need to think about this question anatomically. If you are injecting something into the delt about 1 inch deep, what major vessel are you going to hit?

 

[howelljolly]

Its not a bad idea to get into the habit of aspirating back. When you start getting onto the lidocaine injections, if you inject that into a blood vessel, that generates... well.... trouble.
arrhythmias and siezures to be precise.

 

[anon-y-mouse]

Thus, there usually is not any harm if an IM medication were pushed into a blood vessel (however, from what I understand, pushing a vaccine into a blood vessel can limit the efficacy of the vaccine).

are you a nurse, med student, or doctor? umm... injecting a local anesthetic into a systemic vessel causes lots of problems among other things. i can also imagine things happening with depot medications, etc. though i can't reliably predict what those would be.
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what i have always wondered about it insulin drip vs subq -- any insights?

 

[howelljolly]

Dudes, open a text book.

Vaccines are designed to mount and Ab-Ag immune response. The vaccine is not a small molecule that should go into the blood stream and be seen by the cell mediated immunity as snack time. The vaccine is chemically bonded to a large protein carrier molecule. It should be injected into the tissue, and hang around long enough to be recognized as a specific antigen for which antibody will be produced.

Insulin drips vs. SQ. Insulin drips are used for hyperglycemic diabetic patients who are hospitalized and can not eat. They are given this along with a metabolically active maintenence drip of a crystalloid with dextrose (D2.5 1/2NS, or D5 1/2NS or something). This gives the patient an Isotonic solution with something to get ATP from (just because they are hyperglycemic and diabetic doesnt mean that you want them to die). So by giving them the dextrose and insulin simultaneously, you are giving them a source of ATP that they can use. At the same time, your friendly neighborhood Nurse is titrating the rate of insulin infusion on an hourly basis so that you can safely bring the hyperglycemia down to normal. Subcutaneous insulin is given for routine basal and prandial glycemic control.

And before someone else asks. Subcutaneous Heparin... The unfractionated form inhibits Clotting Factors Xa and IIa equally, whereas the low molecular weight form inhibits Factor Xa much more strongly. When heparin is injected subQ, the unfractionated form is used. Within the subQ tissue, the low molecular weight fraction of this unfractionated heparin more easily diffuses out of the subQ tissue and into the blood and effectively acts like the LMW heparin, more strongly inhibiting Factor Xa activity. Why bother?? Because LMW heparin is nearly twenty times more expensive than the unfractionated form. So, give the cheaper form and let the body fractionate it. And you thought that there was a scientific reason for this.....

 

[anon-y-mouse]

Dudes, open a text book.

Vaccines are designed to mount and Ab-Ag immune response. The vaccine is not a small molecule that should go into the blood stream and be seen by the cell mediated immunity as snack time. The vaccine is chemically bonded to a large protein carrier molecule. It should be injected into the tissue, and hang around long enough to be recognized as a specific antigen for which antibody will be produced.

Insulin drips vs. SQ. Insulin drips are used for hyperglycemic diabetic patients who are hospitalized and can not eat. They are given this along with a metabolically active maintenence drip of a crystalloid with dextrose (D2.5 1/2NS, or D5 1/2NS or something). This gives the patient an Isotonic solution with something to get ATP from (just because they are hyperglycemic and diabetic doesnt mean that you want them to die). So by giving them the dextrose and insulin simultaneously, you are giving them a source of ATP that they can use. At the same time, your friendly neighborhood Nurse is titrating the rate of insulin infusion on an hourly basis so that you can safely bring the hyperglycemia down to normal. Subcutaneous insulin is given for routine basal and prandial glycemic control.

And before someone else asks. Subcutaneous Heparin... The unfractionated form inhibits Clotting Factors Xa and IIa equally, whereas the low molecular weight form inhibits Factor Xa much more strongly. When heparin is injected subQ, the unfractionated form is used. Within the subQ tissue, the low molecular weight fraction of this unfractionated heparin more easily diffuses out of the subQ tissue and into the blood and effectively acts like the LMW heparin, more strongly inhibiting Factor Xa activity. Why bother?? Because LMW heparin is nearly twenty times more expensive than the unfractionated form. So, give the cheaper form and let the body fractionate it. And you thought that there was a scientific reason for this.....

Dude, I understand why SC vs drip insulin is given in both those instances, but there have been other times where the order has just been kind of capricious, even according to my medicine attending.

At any rate, as as for your UFH vs LMWH thing. What about the ESSENCE trial?

"CONCLUSIONS: Enoxaparin significantly reduced the triple end-point of recurrent angina, MI and death at 14 days, with a sustained effect at 30 days. There was no increase in the total number of hemorrhages; however, a significant increase in the rate of minor hemorrhage was observed."

If this were my grandfather, I would definitely give LMWH versus UFH, and you'd be pretty cruel not to do the same, especially if he ended up being in that n% "adverse effects" group. LMWH is standard of care.

 

[howelljolly]

Maybe because the doctor is too lazy to think like a pancreas, and he wants to make the nurse titrate the dose.

As far as the heparin thing, I believe that the level of evidence is actually weak enough to allow hospitals to put their own cost effective policies in place. I learned something to that effect recently, but I cant remember the details.

 

[anon-y-mouse]

Maybe because the doctor is too lazy to think like a pancreas, and he wants to make the nurse titrate the dose.

As far as the heparin thing, I believe that the level of evidence is actually weak enough to allow hospitals to put their own cost effective policies in place. I learned something to that effect recently, but I cant remember the details.

Probably too lazy... or arguably overworked. It's not like we get paid by the hour here.

About the heparin thing, here is what uptodate says.

Guidelines on heparin use — To summarize the above observations, enoxaparin and UFH appear to be of equal efficacy when patients with UA and NSTEMI are evaluated in the aggregate. However, patients who are managed by a conservative strategy appear to have fewer adverse cardiovascular events when treated with enoxaparin compared to UFH. On the other hand, for patients undergoing an early invasive strategy, UFH may be preferable due to the increased risk of bleeding with enoxaparin seen in the SYNERGY trial. (See "SYNERGY trial of use in PCI" above).

The 2007 American College of Cardiology/American Heart Association (ACC/AHA) guidelines on non-ST elevation ACS reached the following conclusions concerning the role of enoxaparin and UFH in such patients [49] :

* Among patients in whom a conservative strategy is selected, either enoxaparin or UFH was recommended, but it was considered reasonable (a weaker recommendation) to prefer enoxaparin (or fondaparinux). The recommended duration of therapy was enoxaparin for the duration of hospitalization (maximum eight days) or UFH for 48 hours.

* Among patients at increased risk for bleeding, fondaparinux was preferred. .

* Among patients in whom coronary artery bypass graft surgery (CABG) is planned within the next 24 hours. UFH was preferred because its anticoagulant effect can be more rapidly reversed than that of enoxaparin. In patients already being treated with enoxaparin, enoxaparin should be discontinued and the patient should be switched to UFH at a dose consistent with institutional practice.

* Among patients who undergo PCI, it was recommended that anticoagulant therapy be discontinued after the procedure in uncomplicated cases.

* Among patients in whom medical therapy is selected after coronary angiography and a heparin has been given prior to angiography, enoxaparin should be continued for the duration of hospitalization (maximum eight days) and UFH should be continued for at least 48 hours or until discharge.

So it seems that UFH and LMWH both have their place, but in the garden variety of heparin usage, LMWH seems to win out... yes, it is a 'weaker' recommendation from the ACC (despite the ESSENCE trial), but if it doesn't meet the "I would do this to my grandfather/parents" test, I strongly feel you're barking up the wrong tree in terms of cost savings, as this decision directly affects morbidity and mortality. If it were my father, I'd want him on LMWH unless he was undergoing some interventional procedure for which quick reversal could be warranted (as above). There are so many other abject wastes of money in the hospital that should be looked at first in my opinion, especially since there is some data to show that certain medications work. At any rate, this is going to be moot, as there is a bevy of anticoagulant medications out on the market awaiting trial! Clopidogrel vs ASA/Dipyradimole in a recent NEJM issue in fact... and all those IIB/IIIA inhibitors, etc. etc.

 

[howelljolly]

What about for DVT prophylaxis?

 

[indo]

Them vaccine proteins'll git digested before you git yer deesired immune response.