Alternative method of adenosine administration in paroxysmal supraventricular tachycardia
Authors: Tangsuwanaruk T , Daengbubpha P , Wittayachamnankul B , Sutham K , Chenthanakij B 
Published: February 2022

Abstract

Funding Acknowledgements
Type of funding sources: Public Institution(s). Main funding source(s): Faculty of Medicine, Chiang Mai University Research Fund

Background
An intravenous adenosine with a double syringe technique is an essential treatment in a patient with paroxysmal supraventricular tachycardia (PSVT). Due to its fast metabolisation (approximate half-life is about 2-5 seconds), it required a fast intravenous injection to make the best outcome in treatment. In some practice, there is an alternative method to administer adenosine by elevating the arm perpendicular to a horizontal plane after injection to facilitate a rapidly injected manner. However, there is no scientific proof of this hypothesis.

Purpose
To compare the successful termination of PSVT with the first dose of intravenous adenosine between usual and the alternative methods. We hypothesised that the alternative method is superior to the usual method.

Methods
We conducted a pilot randomised controlled trial in the emergency department. Eligible patients were adult patients with stable PSVT who failed termination by vagal manoeuvre. Eligible patients were randomised with variable block sizes (block sizes 2, 4) and allocate into the usual group (double syringe technique of 6 milligrams adenosine), or the alternative group (same as the usual method, then immediately followed by elevating arm to 90 degrees perpendicular to a horizontal plane for 10 seconds). We estimated that an alternative method would increase the success rate by about 5%. We would need to enrol 700 patients. However, a pilot chart review in our setting showed about 50 patients per year were eligible. At this rate of enrolment, the number of cases would not be feasible to achieve in the available period. Therefore, we conduct this study as a pilot study. The primary outcome is the success rate in terms of termination of PSVT on an electrocardiogram (ECG). Secondary outcomes are complications within a minute after adenosine administration. We used intention-to-treat analysis.

Results
Thirty patients were randomised and allocated in each group. The success rate was 86.7 % in the alternative group and 80% in the usual group (risk difference 6.7%, 95% confidence interval -19.9 to 33.2%, p 1.00). Light-headedness was 1 of 15 patients (6.7 %) in the alternative group and none in the usual group (risk difference 6.7%, -6 to 19.3%, p 1.00). Palpitation was 1 of 15 patients (6.7 %) in the usual group and none in the alternative group (risk difference -6.7%, -19.3 to 6%, p 1.00). No cardiac arrest occurred after adenosine administration in both groups.

Conclusions
No evidence of the difference between alternative and usual methods, in terms of the successful termination of PSVT and complication occurrences within a minute after adenosine administration. An alternative method of adenosine injection may be an option for the patient with PSVT. However, this is a pilot study that might not demonstrate any statistical significance because of few participants. Further study might be conducted as a multicentre design to fulfil adequate numbers of the participant.