Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

On the relative wisdom of synchronized cardioversion without sedation – Part IV


Continued from On the relative wisdom of synchronized cardioversion without sedation – Part I, then followed by On the relative wisdom of synchronized cardioversion without sedation – Part II, and most recently On the relative wisdom of synchronized cardioversion without sedation – Part III, which began my response to Tom Bouthillet, at Prehospital 12 Lead ECG, writing On the relative wisdom of synchronized cardioversion without sedation.

Should we sedate hypotensive patients?

Special Scenarios

1. Hypotensive Medical Patient-the patient’s blood pressure is never too low to get adequate pain control and sedation. Start them on a pressor and give them comfort. Fentanyl/versed is probably a good combination. Maybe in the future ketamine/versed.[1]

This is from Dr. Scott Weingart, an emergency physician publishing a great blog/podcast about using critical care treatment in the ED. He is advocating for more aggressive care in the ED. Does that mean that we should not be doing the same thing in EMS?

The reason he is advocating for more aggressive care in the ED is for the patients.

Do the same patients deserve lesser care from EMS?

Does EMS lack the ability to provide high quality aggressive care?

What can EMS do to improve the care of these patients without creating an unsafe environment for patients?

Dr. Weingart is also describing post-intubation sedation, so this is not entirely the same as pre-cardioversion sedation. He does cover this in Procedural Sedation – Part I and EMCrit Podcast 29 – Procedural Sedation, Part II.

What should be an appropriate dose of midazolam for an awake patient with VT (Ventricular Tachycardia) at a rate of 170 and a blood pressure of 74/52?

When discussing the probably hypertensive excited delirium patient, I wrote –

If limited to midazolam, what really are the difficult to manage problems, if we start with 10 mg IM for this 45 kg patient? 0.22mg/kg IM (IntraMuscular).[2]

With these patients, we should avoid the recommended dosage range, but in opposite directions. This time, we want to use a lower dose than recommended. A good sized dose for a 45 kg patient is probably 0.5 mg to 1.0 mg IV (IntraVenous), s l o w l y flushed in, over a minute or two, with the patient’s arm raised to help the medication to get to the central circulation. Then wait a minute, or two, for the midazolam to take effect. The dose may need to be repeated. It may be a good idea to alternate doses of midazolam with 25 mcg to 50 mcg fentanyl.

Is the circulation to the brain impaired?

Not enough to cause confusion, but the circulation probably is impaired. Therefore, we should be using smaller doses than recommended for a stable patient.

Is the peripheral circulation impaired?

Maybe. This is why we want to flush the midazolam into the central circulation. We do not want to make this a fast push. Over 1 – 2 minutes is fast enough. Side effects are mostly related to two things. The dose and the rate of administration. We want to avoid the side effects of increasing hypotension and respiratory depression/arrest.

It is important for the medication to reach to the central circulation before cardioversion.

If we do not flush the midazolam into the central circulation (a 20 ml syringe is a good idea), the medication may not have any effect until after cardioversion. That is a treatment failure. We have provided all of the risk of treatment, but none of the benefit.

Maybe we have provided a little retrograde amnesia, but for awake cardioversion, I would not expect retrograde amnesia to significant alter the memory of the extreme pain of cardioversion.

We are not interested in the metabolism of midazolam until after the patient’s rhythm has been treated. If the cardioversion is successful and the patient’s blood pressure returns to something more stable, the effective dose in this patient will be significantly lower than the recommended dose of midazolam, therefore the midazolam should be cleared more quickly and with fewer complications than with any recommended dose for a stable patient.

Updated 02/08/11 to reflect the new blog address for EMCrit. http://emcrit.org/ The old links did not redirect appropriately.

Footnotes:

[1] Hypotensive Medical Patient
EMCrit Podcast 21 – A Bad Sedation Package Leaves your Patient Trapped in a Nightmare
Special Situations
EMCrit
Supplementary material and Podcast

[2] A Naked Woman – TOTWTYTR – Part I
Rogue Medic
Article

.

Trackbacks

  1. […] This post was mentioned on Twitter by EMS Blogs, Chronicles of EMS. Chronicles of EMS said: On the relative wisdom of synchronized cardioversion without sedation – Part IV http://bit.ly/ha1UOf Via @EMSblogs #CoEMS […]

  2. […] To be continued in On the relative wisdom of synchronized cardioversion without sedation – Part IV. […]

Speak Your Mind