Cardiac arrhythmias and conditions in children certainly warrant our concern. The entire clinical spectrum is challenging to evaluate and manage; from the subtle presentation of heart failure or overt shock. Additionally, management may also warrant concern for other important diagnoses (ex, Sinus Bradycardia and Eating Disorders) and at other times, management requires going against dogma (SVT and Adenosine). While all of this can be quite complicated, there are occasions when a simple approach can be the best answer. Let’s take a brief minute to digest a Morsel about Upside Down Vagal Maneuvers for SVT:

Supraventricular Tachycardia (SVT)

• Supraventricular Tachycardia (SVT) is the most common symptomatic dysrhythmia in infants and children.
  • Usually caused by an accessory AV pathway.
  • Can typically cause heart rates in children of >200 bpm.
  • Has two peaks in incidence: During 1st year of life and after 6 years of age.

• Management consists of: [Bronzetti, 2018; Lewis, 2017]
  1. ABC’s
  2. Vagal Maneuvers (see below)
     
  3. UNstable SVT?
     • Synchronized Cardioversion for Altered Mental Status.
       
     • Also consider synchronized cardioversion for Impaired perfusion / Hypotension if adenosine administration will be delayed.
  4. Adenosine
     • Using higher initial dose (0.2 mg/kg) as initial therapy has been advocated. [Lewis, 2017]
       
     • This can help reduce risk of refractory SVT.
  5. Consider Refractory SVT:
     1. Especially for the children who are under 1 year of age. Know what your next steps are.
     2. Procainamide has been shown to be more effective than Amiodarone.
        

Vagal Maneuvers

• Vagal maneuvers are recommended as first line option. [Bronzetti, 2018; Hare, 2015]
  • Can be used outside of the hospital (ie, at home)!
  • Can be employed quickly during initial assessment in the ED.
  • Thought to work best if performed early, before the adrenergic tone rises too greatly, so may work better at home than in ED. [Bronzetti, 2018]

• Vagal maneuvers are thought to work by: [Hare, 2015]
  • Transient increase in intrathoracic pressure,
  • Stimulation of carotid and aortic arch baroreceptors,
  • Leading to increased parasympathetic response.

• Include: [Bronzetti, 2018; Hare, 2015]
  • Carotid Sinus Massage
    • Often mentioned, but with limited data.
      
    • Currently only found to be modestly effective [Collins, 2015]
  • Mammalian Diving Reflex
    • The exact means to perform this is not clear, but references currently describe: [Smith, 2012]
      • Compete facial immersion in iced water for 30 seconds
      • Covering the face with an ice pack (10 degrees) for 30 seconds.
    • Effective in pre-hospital and hospital environments. [Smith, 2012]
  • Valsalva Maneuver
    • First described as a means to expel purulent material from middle ear (gross). [Bronzetti, 2018]
    • Performed by exhaling against a closed glottis.
    • Problem = telling a child to “bear down like you are having a bowel movement” will generally not produce the results that you were expecting… so you can:
      
      • Have an older child attempt to blow through a partially occluded straw / tubing.
      • Have older child sit in semi-recumbent position and blow into 10 ml syringe for 15 seconds, attempting to move the plunger 1 ml.
  • Modified Vagal Maneuvers
    • Inverted position can augment venous return and suddenly stretch the atrium – both possibly improving response. [Bronzetti, 2018]
    • Older children
      • Leg Lift Valsalva Maneuver has been used successfully in adults. [Michaud, 2017]
        • Patient performs traditional Valsalva strain for 60 seconds and then,
        • Immediately after strain, is laid supine with legs raised to 45 degrees for 15 seconds.
        • After leg raise, the patient is returned to semi-recumbent position.
        • Not studied in children… but, let’s be honest, some adults are like big babies so…
      • Handstand for 30 seconds and then return to supine position [Bronzetti, 2018; Hare, 2015]
        • Can be done at home (obviously)
        • In the ED, providers can hold kid’s feet to ensure no accidental trauma.
        • Found to be safe and effective. [Hare, 2015]
    • Younger children (<30 kg) –
      • The inverted position can still be beneficial, but they cannot do handstands… so…
      • GENTLY hold the infant “Upside Down” for 30 seconds and then return to supine position [Bronzetti, 2018]
        • Can be done safely and effectively in the ED [Bronzetti, 2018]
        • Can work better than traditional vagal maneuvers in children. [Bronzetti, 2018]

Moral of the Morsel

• Have a Plan and Act Early! Acting early to treat SVT can help prevent refractory SVT.
• Get them inverted… safely! The inverted position can have improved rates of cessation of SVT. Whether by feet elevation, or handstand, or by just holding the young ones upside down, there appears to be an augmented vagal response. Just don’t drop the kid!

References