SVT

Question 1

If the patient is not compromised or is mildly compromised

Answer 1

• Try up to two Valsalva manoeuvres.
• Gain IV access and administer adenosine IV if the rhythm fails to revert and the patient has a history of recurrent SVT that is known to be responsive to adenosine.

Question 2

If the patient is moderately compromised

Answer 2

• Try up to two Valsalva manoeuvres.
• Gain IV access and administer adenosine if the rhythm fails to revert.

Question 3

If the patient is severely compromised

Answer 3

• Reconsider the diagnosis as it is rare for SVT to cause severe compromise.
• If the patient can obey commands:
  a) Attempt up to two Valsalva manoeuvres provided this is feasible.
  b) Gain IV access, administer 1 mg/kg of ketamine IV (up to a maximum of
  100 mg) to induce dissociation, and
  c) Cardiovert using maximum joules in synchronised mode. Repeat this once
  if the rhythm fails to revert.
• If the patient cannot obey commands:
  a) Cardiovert using maximum joules in synchronised mode. Repeat this once if the rhythm fails to revert, or
  b) Attach and use a defibrillator in automatic mode if you cannot use it in manual mode.

Question 4

Adenosine is contraindicated if the patient has:

Answer 4

a) Known sick sinus syndrome without an internal pacemaker, or
b) Previous 2nd or 3rd degree heart block without an internal pacemaker, or
c) Had a previous heart transplant without an internal pacemaker.

Question 5

patho of the valsalva manoeuvre

Answer 5

A Valsalva manoeuvre creates a sustained positive pressure in the thorax. This causes a reduction in venous return which causes sympathetic nervous system stimulation. When spontaneous breathing recommences, a sudden increase
in arterial pressure results in vagal stimulation that may terminate SVT in approximately 40% of patients.

Question 6

steps of the valsalva manoeuvre

Answer 6

a) Place the patient in a sitting position.
b) Ask the patient to blow as hard as possible into a 10 or 20 ml syringe to try
and move the plunger.
c) Continue the manoeuvre for a minimum of 15-20 seconds.
d) When the patient stops blowing, simultaneously lay the patient flat and
raise their legs.