LAUSR

Type of funding sources: None. Intravenous double-syringe technique (DST) of adenosine administration consists of an intravenous bolus of adenosine via three-way stopcock followed by an immediate 10-20ml sodium chloride 0.9% flush and is the recommended first-line treatment for stable supraventricular tachycardia (SVT). However, an alternative single-syringe technique (SST) method for adenosine administration has been described. This consists of diluting adenosine with sodium chloride 0.9% to a total volume of 15-20ml and was recently found to be potentially beneficial in several studies. We aimed to perform a meta-analysis of the SST versus the DST of adenosine administration as treatments for SVT. We systematically searched EMBASE, PubMed, Cochrane, and ClinicalTrials.gov databases for randomised controlled trials (RCTs) and non-randomised studies of intervention (NRSIs) comparing the DST to SST adenosine administration in patients with SVT. The risk of bias was assessed by RoB-2 for RCTs and ROBINS-I for NRSIs. Outcomes included termination rate, termination rate at first dose, total administered dose, adverse effects, and discharge rate. We included four studies (three RCTs and one NRSI) with a total of 180 (60.55% female) patients, of whom 100 (55.55%) underwent the SST of adenosine administration. The three RCTs were considered of some concerns due to no pre-specified analysis in all studies and deviation from the intended intervention in one study. The NRSI was considered to carry a serious risk of bias by no analysis method that controlled for confounding, the possible influence of the outcome measure by knowledge of the intervention received, and no pre-specified analysis. No significant difference was found between treatment groups regarding termination rate (p = 0.22, Fig 1a), termination rate restricted to RCTs (p = 0.49, Fig 1b), total administered dose (p = 0.29, Fig 2a) and discharge rate (p = 0.1, Fig 2b). Termination rate at first dose (OR 2.87; CI 1.11-7.41; p = 0.03; I² = 0%, Fig 1c) was significantly increased in patients who received the SST. Major adverse effects were observed in only one study, with one patient suffering extravasation and phlebitis in the DST group. To our knowledge, this is the first meta-analysis studying SST versus conventional DST for the management of SVT. This study suggests that the SST may be as safe as DST, equally effective for SVT termination, or even potentially more effective with the first dose. The SST would represent a simpler and more rapid approach, obviating the need for syringe switching or three-way stopcock, and reducing the margin of error in adenosine administration. To our knowledge, this is the highest quality evidence to date. Our results demonstrate that the current evidence is sufficient to support both SST and DST. However, favouring one technique over the other is not feasible given the limited sample size.