In this episode, I’ll discuss an article comparing different methods of administering adenosine.
Because the half-life of adenosine is measured in seconds, administration must be rapid and followed by a 20 mL saline flush for enough of the medication to reach the site of action before it is metabolized. This has been traditionally accomplished by preparing a syringe of adenosine and two 10 mL saline flushes, and having a nurse administer them in rapid succession. Some practitioners prefer to hook the medication syringe and flush up to a 3-way stock cock to reduce the number of syringe changes and time between medication administration and saline flush.
However, another proposed method of administration is to draw up adenosine into a 20 mL syringe and qs to 20 mL with saline, allowing for a single syringe administration. This method was studied, and results were published in the journal Academic Emergency Medicine in October 2019.
The study was a single-center, prospective, observational study of patients presenting to the emergency department in supraventricular tachycardia treated with adenosine. Study medication was prepared by a pharmacist and the method of administration was at the preference of the physician. Adenosine was either prepared as a single syringe combined with a saline flush to a total of 20ml or as the conventional method using two separate syringes where adenosine was followed immediately by a 20 mL saline flush.
The rates of conversion from supraventricular tachycardia to normal sinus rhythm were recorded. A total of 53 patients were analyzed. The median number of doses administered in the single syringe arm was one compared to three in the two‐syringe arm.
Conversion to normal sinus rhythm with the first dose of adenosine was 73.1% and 40.7% for the single‐syringe and conventional method respectively (p=0.0176).
Successful conversion after taking multiple doses into account, was 100% in the single‐syringe arm and 70.4% in the two‐syringe arm (p=0.0043).
Adverse effects were minimal in both groups, zero in the single‐syringe arm and one in the conventional cohort.
Conclusion
The authors concluded:
A single‐syringe method of adenosine delivery is non‐inferior to the conventional two‐syringe method. Additionally, no adverse events were observed in the single‐syringe method.
While this study was designed as a non-inferiority trial, the effects of single syringe administration of adenosine seemed impressive. It is logical that the single syringe method, being less complex and not subject to delay between medication and flush administration, would prove to be a more effective method of administration.
Members of the Hospital Pharmacy Academy have access to in-depth and practical training from a pharmacist’s point of view on SVT treatment and managing tachycardias in the emergency department. To get immediate access, go to pharmacyjoe.com/academy.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.
I have been using this method exclusively over the past year or so and from my own unblinded nonrandomized case retrospective analysis can comfortably report a higher incidence of conversion from the 6mg particularly. In fact, historically we have very poor response from 6mg of adenosine when given undiluted iv push however since changing our processes I have been able to turn the harshest criticists into from non-believers to believers… Additionally, patients seem to subjectively tolerate the diluted version better…..