Cardiac CTA

Hi, jfelicia71. We have just fairly recently started doing cardiac CTA's. Our guy will use up to probably 20 mg of metoprolol - he says he has never had to use more. But it is in 1 mg increments, rather than 5 mg increments. He is more likely to use only 5 - 10 mg of metoprolol. I have heard of other centres using higher doses - up to 50 mg. It will be good to get some cases under our belts, so we can see what works, and how fast, and beyond what dose there's really no point in adding more. . .

I have heard of other centres using higher doses - up to 50 mg. It will be good to get some cases under our belts, so we can see what works, and how fast, and beyond what dose there's really no point in adding more. . .

1. Administer 15 mg of Lopressor IV over 7 minutes

2. Wait 8 minutes, if HR is not down to 60 bpm

3. Administer an additional 35mg of Lopressor IV over 8 minutes

4. VS q 2 minutes

5. No Lopressor if P-R interval is .24 or greater

6. Stop if systolic reaches 90 or diastolic reaches 60

We have found that if the first 15 mg of Lopressor doesn't get the HR down to 60 the rest is like pushing Kool-aid. However, with that said...if we don't push the entire 50 mg of Lopressor the cardio's will have our heads on a platter.

We have been doing them since the beginning. One of our cardio's (a real PIA) was a partner in the development of the Cardiac CTA and we were one of the first 3 hospitals where it was available. He, the PIA, has a 128 slice scanner in his office and it does not require any Lopressor, they get clear scans no matter the heart rate or arrhythmia. I want one!

We have a dual source CT scanner and still use IV Beta Blockers. The cardiologists say the images are so much clearer.

1. We hope if pt is on oral Beta Blockers or Calcium Channel Blockers that they will take them the am of their test but sometimes they get confused and forget.

2. If Heart Rate is >70 or irregular we give up to 40mg IV Metoprolol

if initial BP is >90-100sys.

3. We treat each pt individually making a nursing judgment depending on their size, VS, how they are feeling, meds they are on etc. I usually start with 5-10mg given over 2-5min. We do not have to get them less than 60 HR. 65 is a good heart rate for younger or obese people, they can use a min dose radiation protocol, and on obese people the images are clearer the slower they are.

4. If the above doesn't work we keep going until the max of 40mg.

In a few rare cases we have consulted with the ct MD and they have had us give some cardizem in addition, see case below.

5. If they have asthma we give Cardizem IV up to 25mg given over 2-5min adjusting to their response. If the heart rate does not come down with the full dose, we can give 20mg Metoprolol in addition (even though they have asthma).

6. If they have more than 2 pvc's in a 10sec tele strip we give 1mg/kg lidocaine up to 100mg, or 150mg in an obese pt.

7. If they have PAC's we are to try the max of Metoprolol that they can tolerate.

8. New this week if they still have freq PVC's or PAC's we call to see if the CT Dr wants to cancel the test. I guess they lose a lot of the images during those premature beats.

Surprisingly most of our pt's have done well but it is scary giving all those medications then they go home. We have had a pt faint recently with a low bp and hr in the 30's after a full dose of metoprolol, cardizem and his nitro, he was a difficult case because of afib, but we got great pictures :) and they did find a lesion so I guess it was worth it.

It seems like pt's already on beta blockers do not respond to the 40 of Metoprolol.

Many days I feel like we medicate the scanner though, not the patient. The goal is always for optimal pictures, but as nurses we have to constantly advocate for our patients and stop with the meds when we feel they are at their max.

We have not started ours yet but will be in the next couple of months and I have heard from one of the CT people that it is preferable to use oral doses if possible rather than IV to slow the rate. It was one dose the night before and then another in the AM I think. It was supposed to be more reliable and gentler (or less reactive) I think.

What do you all know about that as a protocol?

I have another question. How long are patients monitored after the metoprolol? And what is the half-life/peak effect of IV metoprolol? I always feel like I'm letting these patients go too soon. Maybe it's just lack of familiarity. . .

Thanks.

I think the peak is about 1 hour and the half life around 4hrs. If we give a small amount 5 or 10mg I usually just keep them our 15 min that we try and keep everyone. But we can give up to 40mg, so those people usually we keep longer, but it is individual depending on how they feel. It seems the one's we give a lot to are the ones already on a beta blocker and they don't feel it. I usually watch the ones that have never had it before a little longer. It is worrisome that by the time they are driving home they are at their peak, this worried me a lot but so far our patients have done well. I tell them not to do anything real exertional for a few hours and don't change positions real fast. If they feel tired after we encourage them to go home and rest. It seems that after the contrast and extra saline fluid their heart rates and BP's go up and they are usually back to their baseline.

We hold the meds if their heart rate is less than 60 or BP less than 100, or their EF is less than 20. We have a dual source scanner so our heart rates have to be less than 70, 60 to 65 is perfect. Hope this helps.

I know this is old but here we give PO Metoprolol 50 mg at hs the night before and 50 mg 1 hr before the study. That wokrs great (hr ususally 50's) the ordering MD orders the meds. I have never had to use more that 15 mg of iv metoprolol. normally I do not have to give anything, except the nitro.

In our hospital the rads. feel that if 10mg IV doesn't lower the rate then higher doses are not going to do it either. We only monitor our patients for 1 hour post procedure. I worked in an ICU for 15 years and usually IV lopressor was given on a Q6 hour interval and the patients HR would start to climb after about 5 1/2 hours, u always knew when it was time for another dose. I do like the idea of measuring PR intervals prior to giving doses as stated above. We don't perform many CTAs anymore as we just opened a cath lab this past summer and most docs want a diagnostic cath. Some of the cases are due to WV medicare/medicaid not wanting to pay for non-invasive procedures even though they cost a 4th of what a cath costs!

I would be happy to fax you a copy of our protocol sheet. we usually have the patients take po lopressor at least one hour before the scan, frankly I think this works better than the IV dosing. I have given as much as 70mg IV, but usually if you havent gotten the HR down by the time you hit 50mg, then most likely will not happen.

We give it in 5 minute increments every 5 minutes. This took a bit of getting use to in the beginning. Also, our docs are not standing in the room with us when we do these cases.

One hospital the protocol was written by the cardiologists and at this teaching hospital it is covered by the radiologists.

I just started in rad a few months ago and have only done a few heart ctas but this is what we do where I work:

#1 16g to RAC, sometimes 18g but we run contrast at up to 8, only @6 on 18g.

#2 we have either 2 med options: 15mg IV lopressor in 5mg doses. when we give this we give it like adenosine, hard and fast. we were lead so they are shooting while we are in there.

if that isn't working, we give 1/2 tab NTG SLG, as long as they don't take ED drugs.

The key for our pictures has been the 16g because they can run the contrast faster and get the images quicker.

We've also recently started hearts for valves and we don't give meds for that, just 16g.