(Last Updated On: October 28, 2015)

Welcome to the second entry in an ongoing series called the Knowledge Bomb!

Description

These entries will contain a short, quick-hitting summary of a recently published piece of literature with major take-home points including the writers (resident) opinion on how it influences their practice, plus an attending response/perspective.


Knowledge Bomb #2

Bomb3Bomb Article

Appelboam A et al. Postural Modification to the Standard Valsalva Manoeuvre for Emergency Treatment of Supraventricular Tachycardias (REVERT): A Randomised Controlled Trial. Lancet 2015.

Click Here To Access The Literature

Design
REVERT: parallel group RCT of patients presenting in SVT to ten hospitals in England (2 academic, 8 community) over a 16 month period.

Inclusion: age >18, suspected SVT at triage or initial evaluation. screened with 12 lead EKG, regular, narrow complex tachycardia, QRS <120ms.

Exclusion: SBP <90mmHg, indication for cardioversion, a. flutter, a. fib, presence of contraindication to valsalva (aortic stenosis, glaucoma, recent MI, retinopathy), inability to perform valsalva or lie flat.

Standard valsalva: semi-recumbent position, blow 40mmHg x15s. (blow into a 10 ml syringe strongly enough to move the plunger).

Modified valsalva: same as above, then laid flat and legs lifted for 15s.

https://www.youtube.com/watch?t=37&v=8DIRiOA_OsA

Outcomes
Primary: restoration of sinus rhythm one minute after Valsalva maneuver confirmed by EKG in intention to treat analysis
Secondary: use of adenosine, use of other emergency treatments for tachycardia, need/reason for hospital admission, ED LOS, adverse events

Findings
93 (43%) of 214 participants in the modified Valsalva manoeuvre group versus 37 (17%) of 214 participants in the standard Valsalva manoeuvre group achieved the primary outcome of sinus rhythm at 1 min (odds ratio [OR] 3·7, 95% CI 2·3–5·8; p<0·0001; table 2). The absolute difference was 26·2%; thus, three patients needed the modified Valsalva manoeuvre to avoid one case of further treatment.
(NNT is actually closer to 4 (3.8)
 
In addition:

  • Statistically significant decrease in patients requiring adenosine or any other emergent treatment of tachycardia in the ED
  • Non-statistically significant increase in adverse events, though these weren’t clinically significant
  • No change in ED LOS, discharge v. admission

Discussion points:

  • Treating clinicians could not be blinded to intervention

Summary
With a NNT of 3.8, the modified Valsalva maneuver appears to be a safe and effective modification to current practice in the treatment of SVT in the Emergency Department

Application to our practice
With the understanding that I may not be decreasing ED LOS or discharging more patients, this article changes my practice in regards to the initial treatment of stable patients who present to the ED with SVT.
Rather than a cursory attempt at Valsalva maneuver while waiting for adenosine, I will now have these patients blow into a 10mL syringe for 15 seconds and then immediately flatten the bed and perform a 15 second leg lift.  I will have the patient attached to the monitor first but I think it would be reasonable to attempt prior to IV placement.  Patients undoubtedly hate the feel of a push of adenosine, and the modified valsalva maneuver appears to be a safe and effective way to increase conversion while avoiding the use of adenosine.
Thoughts on this? Lets get the discussion started below…