A question about Adenosine

DeadHeadRN, BSN, RN · Jan 29, 2011

You guys are absolutely right. My bad I was confusing the cardizem and the adenosine (as far as IVP time, not action). Maybe that's a sign that I should go to bed. I did just work 14 hours and I probably should be sleeping not on the computer.

But I'm glad to see you guys are paying attention!

LegzRN · Jan 29, 2011

This is true also. Sometimes it takes multiple doses to convert the pt back to sinus. We have a lady who comes into my ED periodically and she always needs 18mg of Adenosine to convert. She knows it too. The first time I triaged her, she walked up to my triage and window and said "I'm in SVT and I need 18mg of Adenosine to convert." We all thought she was a kook, but she was absolutely right. Now we see her coming and we get out the correct dose for her, give it to her and send her on her way.

I hope you gave it as 6mg + 12mg instead of 18mg all at once. If so, I've never heard of that.

Aerin · Jan 29, 2011

Thanks everyone, my friend feels much better knowing that the heart doesn't stop in all cases, everytime. Or if it does, it's just for a second. Just in case it ever happens again.

Again, thanks for the peace of mind. :)

Medic2RN, BSN, RN, EMT-P · Jan 29, 2011

I haven't pushed adenosine as a nurse, but I have on a few occasions as a paramedic. Adenosine causes a transient heart block in the AV node which sometimes causes that few seconds of asystole on the monitor, but since it has such a short half life, it should be temporary. An IV in the AC was the site of choice. It is fast push followed by a fast flush push as others have mentioned. We also kept a box of aminophylline handy in case the asystole was sustained since aminophylline is an adenosine antagonist.

We used escalating doses of 6mg, 12mg, and then 18mg. The most I've ever had to push was 12mg.

I never liked seeing that transient asystole!

GHGoonette, BSN, RN · Jan 29, 2011

I haven't pushed adenosine as a nurse, but I have on a few occasions as a paramedic. Adenosine causes a transient heart block in the AV node which sometimes causes that few seconds of asystole on the monitor, but since it has such a short half life, it should be temporary. An IV in the AC was the site of choice. It is fast push followed by a fast flush push as others have mentioned. We also kept a box of aminophylline handy in case the asystole was sustained since aminophylline is an adenosine antagonist.
We used escalating doses of 6mg, 12mg, and then 18mg. The most I've ever had to push was 12mg.
I never liked seeing that transient asystole!

I see everyone refers to "transient asystole" but this paragraph from the FDA notes interested me:

Heart Block

Adenosine injection exerts its effect by decreasing conduction through the A-V node and may produce a short lasting first-, second- or third degree heart block. Appropriate therapy should be instituted as needed. Patients who develop high-level block on one dose of Adenosine should not be given additional doses. Because of the very short half-life of Adenosine, these effects are generally self-limiting.

Transient or prolonged episodes of asystole have been reported with fatal outcomes in some cases. Rarely, ventricular fibrillation has been reported following Adenosine injection administration, including both resuscitated and fatal events. In most instances, these cases were associated with the concomitant use of digoxin and, less frequently with digoxin and verapamil. Although no causal relationship or drug-drug interaction has been established, Adenosine should be used with caution in patients receiving digoxin or digoxin and verapamil in combination. Appropriate resuscitative measures should be available.

mcknis · Jan 29, 2011

Also regarding the Adenosine dose... 6mg, and if 6 doesn't work, then 12mg, and if 12 doesn't work, then an additional 12 mg. This is per ACLS guidelines. I have seen the brief pause, but it is a brief spell.

JSTARZ · Jan 29, 2011

Personally I worked on a telemetry unit for one year and we usually gave it to cardiovert. So yes! In my pratice the purpose has always been to restart the heart in a "better" rhythm. When used to cardiovert it should be pushed VERY FAST and flushed with NS VERY fast!!! Yes it is a little scary to do. My hands got sweaty and my heart raced EVERY time I pushed this med for cardioversion. Ive only had one situation where it coded a patient, thank GOD the crash cart was present, as it should be. Hope this helps!

MAISY, RN-ER, BSN, RN · Jan 29, 2011

Adenosine is administered quickly with concurrent 10-20ml flush-we use needleless system with pigtail so that flush is less than 2 inches away...raise arm...period of asystole then hopefully conversion. In my facility, the physician is required to push the first dose. Since it's life is only seconds it is important it is flushed immediately and fast.

I believe it is metabolized by red blood cells, thus the quick life. It is not uncommon to NOT work due to improper administration techniques.....so not surprised it takes awhile to convert.

It can also be used in an IO-guess you'd lift the leg.

M

ObtundedRN, BSN, RN · Jan 29, 2011

I have never personally given Cardizem given for SVT, only to pts for rapid Afib, at least in the ED.

I just had to point out that rapid Afib is included under the umbrella term of SVT, so cardizem is correct. If the Adenosine doesn't cause a pause and convert the SVT, then the SVT is most likely Afib or Aflutter and cardizem should be used. Typically in Afib or Aflutter, the adenosine will slow the heart rate, and then go back up.

Btw, the longest pause I've seen was about 12 seconds.

Larry77, RN · Jan 30, 2011

I've given Adenosine at least 100 times and if you give the right dose for the patient (really is pt dependent, that's why you try the smaller dose first) the heart "resets" usually seen with a short asystole...there has been a few times where we had at least a 6 second asystole on the monitor and everyone in the room holds their breath until the heart starts again.

Just remember to warn your patient that they are going to feel terrible but only for a few seconds...if they have had it before they will not be looking forward to having it again. I give it either using a 3-way stop-cock with two nurses and you give the med as fast as possible followed directly with a 10-20ml NS bolus, or I have given it with a fast running bag of NS low in the line and in that case I usually raise the limb if possible just to help it get to the heart faster.

If the patient has had it before and they know they take 12mg believe them because it has in the past and the 6mg isn't going to do anything.

Sometimes you have a fast narrow complex tachycardia that you aren't sure if it's an A-Flutter/A-fib or SVT so you try 6mg Adenosine so you can get a good look (usually on a sicker patient)...

I think it's really fun to give and very rewarding because it works most of the time and the patients often times feel better and go home.

DeadHeadRN, BSN, RN · Jan 30, 2011

I hope you gave it as 6mg + 12mg instead of 18mg all at once. If so, I've never heard of that.

Yes Legz, 6 and then 12, not all at once.

MassED, BSN, RN · Feb 2, 2011

Just a quick question.
Does Adenosine always stop your heart? I had a friend who had SVT and a HR of 280 and took it and she said she remembered feeling like something was pulling out of her body, limb pain, but stayed conscious. Her pulse went down to 125 in 10 seconds. Then she got started on Cardizem.
Is that abnormal?
Thanks for reading.

No. Not abnormal. Lots of patients report all sorts of sphincter tightening sensations.... all of which include dread and sense of impending doom. I would too if my heart had a long frightening pause.... it's a pucker situation, for sure.