SVT in a pediatric patient? Try chilling them out with some ice.


    SVT in a pediatric patient? Try chilling them out with some ice.

    A 3 week old male, born NSVD 40w6d, presents to the ED with 2 days of feeding intolerance. Initial vitals show a heart rate of 260, bp 83/51, RR 40, sat 100% RA, temp 37C. You quickly get an EKG pictured below that shows a regular, narrow complex tachycardia consistent with SVT. What is your next move?

    In a stable patient with SVT, consider eliciting the diving reflex.  


    What is the diving reflex?

    It’s a cardiovascular reflex first noticed in oceanic mammals, specifically seals, that frequently undergo deep dives to cooler depths. The purpose of the reflex is two fold: 1) to increase the efficiency of oxygen consumption by decreasing the heart rate 2) to redirect blood flow through peripheral vasoconstriction.


    How does it work in humans?

    The reflex is mediated by trigeminal nerve temperature receptors in the face. Once stimulated, nerve fibers carry a signal to the trigeminal nerve sensory nucleus in the pons. The trigeminal nerve sensory nucleus then activates the vagus nerve in the medulla leading to increased vagal tone on the heart with and slowing of AV nodal conduction.

    How do you elicit the reflex?

    Unfortunately there isn’t a standardized way to perform this procedure and limited quality data exists. The article below suggests the water be at least 10C for maximum effect and for at least 40seconds.  Practically speaking, take a bag of crushed ice, gently apply the bag across the nasal bridge, forehead without occluding the nostrils or mouth, and apply gentle pressure for 40 seconds. A few studies cited by this review article from the 80s-90s suggest high rates of spontaneous conversion amongst the pediatric population.


    TLDR: If taking care of a pediatric patient with SVT, chill them out with some ice for 40seconds.



    Smith G et. al. Use of the human dive reflex for the management of supraventricular tachycardia: a review of the literature. Emerg Med J. 2012 Aug;29(8):611-6

    • Welcome! This is the website for the Mount Sinai Emergency Ultrasound Division. It serves as an information resource for residents, fellows, medical students and others seeking information about point-of-care ultrasound. There is a lot ofRead more

    • renal handling of water

      If you were on a tea & toast diet, how much water would you need to drink before you develop hyponatremia? I haven’t seen anyone work out the numbers before so here are my calculations. AndRead more

    • acute acidemia physiology

      As alluded to in the first post, don’t be fooled by a “normal” potassium in the setting of DKA because osmotic diuresis and H+/K+ exchange means that total body potassium is actually LOW. You all knowRead more

    • renal handling of potassium

      the first symptom of hyperkalemia is death Earlier post covered temporizing measures to counter hyperkalemia — namely, intracellular shift, increasing cardiac myocyte threshold potential. Give furosemide if the patient still urinates and consider dialysis, but then askRead more

    • bicarbonate revisited

      Previous post reviewed the safety of balanced crystalloids in hyper K. But what was up with serum bicarbonate decreasing with saline administration? This post introduces a new way of looking at the anion gap to possiblyRead more

    • hyperkalemia and balanced crystalloids

      Is it safe to give LR or plasmalyte to a hyperkalemic patient (these balanced crystalloids have 4-5 mEq/L K as opposed to 0 mEq/L K in normal saline)? Postponing the discussion of renal handling of potassium toRead more

    • hyperkalemia physiology

      You’ll likely encounter hyperkalemia on your next Resus / Cardiac shift, and you’ll instinctively treat it. But take a moment to review the fascinating physiology behind the “cocktail”! First, consider how K+ is buffered byRead more

    • Slow down your tachycardia (but not really)

      You’re sitting in resus bemoaning the departure of your most beloved attending when suddenly a patient wheels in without warning. The patient looks relatively stable but the triage RN tells you her heart rate wasRead more

    • Otitis externa: use the ear wick!

      Acute otitis externa (AOE) is a common complaint seen in pediatric as well as adult emergency departments. AOE is typically not accompanied by acute otitis media, although concurrent cases are possible. Also called “swimmer’s ear”Read more