UMEM Educational Pearls

Category: Pharmacology & Therapeutics

Title: Esmolol for Refractory Ventricular Fibrillation (VF) or Pulseless Ventricular Tachycardia (VT)

Keywords: esmolol, cardiac arrest, ventricular tachycardia, ventricular fibrillation (PubMed Search)

Posted: 9/5/2020 by Ashley Martinelli (Updated: 10/24/2020)
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Patients with cardiac arrest due to VF/VT have a higher likelihood of survival compared to those with unshockable rhythms.  Unfortunately some will still not survive even with following the AHA/ACLS algorithms leading to “refractory VF/VT.”  The survival rate of refractory VF/VT is 3-15%, with poor neurologic outcomes. 
 
Esmolol has been proposed as a treatment for the electrical storm of VF/VT to counteract the deleterious effect of beta receptor stimulation by epinephrine.
 
A recent meta-analysis of 3 trials of beta-blockade vs control patients for refractory VF/VT found:
 
Beta-blockade
N=22
Control
N= 44
OR/CI
Temporary ROSC, n (%)
19 (86.4)
14 (31.8)
OR 14.46, 95% CI 3.63-57.57
Sustained ROSC, n (%)
13 (59.1)
10 (22.7)
OR 5.76, 95% CI 1.79-18.52
Survival with neurological function, n (%)
6 (27.3)
4 (9.1)
OR 4.42; 95% CI 1.05-18.56
 
Takeaway: Esmolol needs to be studied further in prospective trials, but may be reasonable to attempt in refractory VF/VT.
 
Esmolol products:
§  Esmolol vial: 10 mg/mL (10mL)
o   Vial strength listed in mg, not mcg
o   Can cause complications with calculations, especially in high risk code scenario
§  Conversion of mg à mcg weight à based calculation 500mcg/kg
§  Do not ask anyone to do this calculation during a code!
§  Esmolol pre-made infusion: 2500 mg/250mL
o   Pump is set up to deliver weight based doses in mcg/kg
o   No mental math required!
 
How to do it at UMMC to limit mistakes in calculation:
1.       Obtain an esmolol pre-made infusion bag
2.       Program the pump for 50 mcg/kg/min continuous infusion (this is a required step in pump programming)
3.       Program the pump to give a 500 mcg/kg bolus x 1
4.       Permit the background infusion to run
5.       Can give an additional bolus of 500 mcg/kg x 1 and increase rate to 100 mcg/kg/min depending on clinical response

References

Gottlieb M, Dyer S, Peska GD. Beta-blockade for the treatment of cardiac arrest due to ventricular fibrillation or pulseless ventricular tachycardia: a systematic review and meta-analysis. Resuscitation 2020;146: 118-125.