Adenosine is an atrioventricular nodal blocking agent that is commonly used in the treatment of supraventricular tachycardia. It is dosed as 6 mg IV Push x 1, followed by dose escalation to 12 mg IV Push if the initial dose was unsuccessful. In patients with central access or prior orthotopic heart transplantation, the initial recommended dose is 3 mg.
Due to its short half-life (< 10 seconds) it is imperative to administer in the most proximal access and follow with a 20 mL bolus of saline. Traditionally this is done using a two-way stopcock.
A new study compared single syringe (adenosine 6mg + 18 mL saline) vs two syringes (adenosine 6mg in one, 20 mL saline in the other) in 53 patients with SVT. The single syringe arm converted to NSR 73.1% after one dose compared to 40.7% in the two-syringe arm (p=0.0176). After up to three doses, the single syringe arm had 100% conversion compared to 70.4% in the two-syringe arm (p=0.0043).
Single syringe adenosine has been recommended in FOAM for several years. Although small, this study is the first to compare the two methods. This method simplifies administration and may improve cardioversion rates.
References
McDowell M, Mokszycki R, Greenberg A, et al. Single-syringe administration of diluted adenosine. Acad Emerg Med. 2019;00:1-3.
