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 Founder and CEO
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 SF General. ALiEM Founder @aliemteam #PostitPearls at Bio:
Michelle Lin, MD