Comparing Prehospital Adenosine Initial Dosing of 6 mg Versus 12 mg for Presumed Paroxysmal Supraventricular Tachycardia (PSVT)

Objectives Adenosine is a common prehospital treatment for paroxysmal supraventricular tachycardia (PSVT); however initial dosing varies and the optimal first dose is unknown. To evaluate the association of the two common initial adenosine dosing regimens (6 mg and 12 mg) with prehospital patient improvement, hospital admission, complications, and death.Methods This retrospective observational study included all 9-1-1 responses with prehospital adenosine administration between 1/1/2022 and 12/31/2022 from the ESO Data Collaborative. Outcomes included EMS clinician documented patient response (improved v. unchanged/worse) to the initial dose, emergency department (ED) dispositions, compressions/cardioversion/pacing after adenosine administration, and death. Descriptive statistics and adjusted odds ratios (OR) were used to compare outcomes for patients who received an initial adenosine dose of 6 mg versus 12 mg.Results We analyzed 11,245 patients that received adenosine from 1,350 EMS agencies. Most received an initial dose of 6 mg (70%, n = 7,825), while 30% (n = 3,314) received an initial dose of 12 mg. Initial pulse rate and systolic blood pressure were similar between groups. Nearly half in the 6 mg group (48%, n = 3,746) received additional doses, compared to 25% (n = 815) in the 12 mg group. An initial dose of 12 mg was associated with 65% increased odds of prehospital improvement (OR: 1.65, 95%CI: 1.49–1.82). Complications including cardioversion (5%, n = 481), pacing (<1%, n = 2), and cardiopulmonary resuscitation (CPR) (<1%, n = 20) were rare. There was no difference in the need for cardioversion, pacing, or CPR between groups (p > 0.05). Amongst EMS transported patients, 25% (n = 2,732) had available ED dispositions. An initial dose of 12 mg was associated with a 28% reduction in odds of admission (OR: 0.72, 95%CI: 0.59–0.87). In total, 2% (n = 48) who received prehospital adenosine and had available outcome data died. Of those, 70% (n = 32) were in the 6 mg group and 30% (n = 14) were in the 12 mg group.Conclusions An initial prehospital adenosine dose of 12 mg was associated with less re-dosing, greater rates of patient improvement, and lower rates of hospital admission compared to an initial dose of 6 mg. Complications requiring interventions and death were rare and similar across dosing regimens.