In this episode, I’ll discuss an article comparing different methods of administering adenosine.
Lead author: Marc McDowell
Published in Academic Emergency Medicine October 2019
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. As this can still be a complicated process, mixing adenosine with 20 mL of saline for a single syringe administration has been proposed as a superior method.
The authors of this study sought to compare the relative efficacy and safety of a single‐syringe of adenosine diluted in normal saline to the standard two‐syringe method for conversion of supraventricular tachycardia to normal sinus rhythm.
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 method of administration was at the preference of the physician. Adenosine was either prepared as a single‐syringe combined with a 0.9% sodium chloride flush to a total of 20ml or as the conventional two separate syringes; adenosine followed immediately by a 20 mL saline flush. 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 first dose of adenosine was 73.1% and 40.7% for the single‐syringe and conventional method respectively (p=0.0176). Successful conversion, after multiple doses, 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.
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 benefit of single syringe administration of adenosine is 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.
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