Last week, Dr. David Johnson shared his trick to elicit a Valsalva maneuver out of his patient. Here’s another trick that I saw one of our EM residents use in an attempt to break a SVT rhythm.



Trick of the Trade

Instruct the patient to blow into a 10 cc syringe in an effort to “blow out” the syringe plunger.1

I was amazed to find a journal article in Emergency Medicine Australia, which documented that an appropriate Valsalva force is generated when a patient is able to move the plunger of a 10 cc syringe by blowing into the syringe! Apparently larger syringes don’t generate enough force (< 40 mmHg) and smaller syringes require too much force (> 40 mmHg).

Smith G, Boyle M. The 10 mL syringe is useful in generating the recommended standard of 40 mmHg intrathoracic pressure for the Valsalva manoeuvre. Emerg Med Australas. 2009;21(6):449-454. [PubMed]
Michelle Lin, MD
ALiEM Editor-in-Chief
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco
Michelle Lin, MD


Professor of Emerg Med at UCSF-Zuckerberg San Francisco General. Founder of ALiEM @aliemteam #PostitPearls
Michelle Lin, MD