[DutchgirlRN]

I've been working at the outpatient imaging center and loving it. I was asked yesterday to cross-train for nuclear medicine. When doing the cardiolytes they give Lopressor IV to bring the HR down. The protocol is 5mg Q 5-15 minutes up to 50mg. The patient then goes home. That scares me to death and I think I would have to refuse to push that much total IV Lopressor? Any thoughts?

[traumaRUs]

Am not sure what it would be for outpatient nursing, but for an acute MI patient or unstable angina, the protocol is 5mg every 5 minutes x3 doses to keep heart rate around 60 bpm to reduce the cardiac stress. Lopressor's half-life is very short which is why it isn't given for long-term BP control via the IV route.

[VivaLasViejas]

FIFTY mg??!! I've pushed as much as 15 mg over a 15-minute stretch, but I'm afraid fifty would drop someone like a rock. WOW. I'm with you, Dutchgirl..........I wouldn't give that much Lopressor either, at least not outside an ICU or critical care setting.

[dianah]

The Lopressor should be titrated for effect, not just "give 50 mg." The end point is to get the heart rate between 50 and 60, for optimum imaging, like for a chest or cardiac CTA (Computerized Tomography Angiogram, or CT Angiogram). If the heart rate falls within the target range after 15 mg IV Lopressor, then no more is given and the patient is quickly imaged, taking full advantage of the medication-induced bradycardia (read: image quickly, before the Lopressor wears off). The patient should be monitored at all times: LOC, NIBP, continuous EKG for HR , RR . . . and as this test IS a Cardiac Stress Test, a crash cart should be in the area (preferably in the room), well-stocked and available at all times, with an ACLS-trained RN and knowledgeable support staff in attendance.

What I'm trying to say is, yes the IV dose given for this test can be higher than routinely given in the ICU. Protocol should clearly outline the maximum dose that may be given, and the patient should be closely monitored while the med. is titrated. (my Epocrates program says, for acute MI, to give 5mg q 2 min X 3 doses, then in 15 min give 50mg (po))

Anecdotally, I've heard our Cardiologist (who does CTAs) tell of some pts whose heart rates didn't respond at all to the max dosage (50mg), with no sequelae. They're imaged anyway, with less-than-desired imaging.

[DutchgirlRN]

I realize that 50mg is not given all at once. On the floor we give 5mg Q4 hours for patients who are NPO so it must not leave the body too quickly. If the doctor wants me to push 5mg of Lopressor every 5 minutes over almost an hour time period I'm afraid I would have to refuse or let the doc push it himself.

I can imagine what could happen to the patient an hour or two later when at home or God forbid driving. I hoped I'm not faced with this because I would quit first.

I've been a nurse for 31 years and have pushed tons of IV meds but have never heard of such an outrageous dose! We use Versed in MRI and monitoring their VS it very effectively relaxes the patient and lowers the HR.

[cateccrn]

The pt. subsequently needs to be monitored in the PACU or RR for at least 1 hour post proceedure. In my experience, if it doesnt work after 3 5mg doses q5 mins, another drug might be a better bet.

[dianah]

The dosage question, then, needs to be addressed through Nursing and possibly through Risk Management, questions answered, protocols written and followed (committee of Cardiology, Pharmacy, Nursing and Radiology).

[vandebar]

Patients having a coronary CTA either inpatient or outpatient may receive up to 5 doses of metoprolol to bring the HR down or below 60. Our policy is 5mg IVP over 2 minutes. The patient is monitored for 5 minutes and the 2nd dose is given if indicated. Monitoring again for 5 minutes and then repeated for a total dose of 25 mg IVP. There has been occasions when the cardiologist ups this to 6 or 7 doses. (Our standing order is for 5). There are also times when the cardiolgist may switch to diltiazem after exhausting the betablocker. This will usually not exceed 2 doses of 10 mg each. I felt the same way when I started in CTA & felt like this was a LOT. It is very well tolerated and I have had no adverse sxs with any patient receiving the betablockers or calc channel blockers.

[Sweetooth EMT-P, RN]

was this someone speaking to you? maybe they said 15 mg which is the normal total dose, and not 50.

Swtooth

[DutchgirlRN]

It's definately 50mg of IV Lopressor given 5mg per push for a total of 50mg as needed to bring the HR down. My experience has been if the HR does not go down sufficiently after 3 doses the remaining 35mg does nothing. The test is done anyway. I've since learned this is common practice where CTA's are done.