External pacing (transcutaneous pacing) [advanced]

Before you start

Indications: haemodynamically unstable bradycardia (unresponsive to atropine); complete heart block; Mobitz type II second-degree heart block when haemodynamically unstable; sudden witnessed asystole secondary to cardioversion/drugs/conduction defect; override pacing of tachycardias refractory to drugs and cardioversion (rarely used)

Setting up

• Anaesthetist must be present to sedate patient (most patients cannot tolerate pacing >50mA)
• Apply 3-lead cardiac monitoring (clockwise from right arm Ride Your Green Bicycle) and connect lead to external cardiac monitor or defibrillator machine
  • Red: anterior aspect of right shoulder
  • Yellow: anterior aspect of right shoulder
  • Green: left anterior superior iliac spine
  • Black: not present on defibrillation machine
• Apply defibrillator pads (in AP position) after shaving chest if required
  • ‘Right’ pad: place longitudinally on left sternal edge
  • ‘Left’ pad: place longitudinally on left paraspinal muscles (in line with anterior pad)
• Connect pads lead to defibrillator machine
• Set defibrillator machine monitoring trace to ‘pads’

Pacing

• Set defibrillator to pacing mode
• Set onscreen pacing rate (default usually  ̴ 70bpm) and energy (default starting energy usually  ̴ 30mA)
• Click onscreen start pacing button
• Observe the monitor to see if QRS complexes follow every pacing spike – if not, increase the energy until they do – ‘electrical capture’ (usually occurs at 50-100mA)
• Next check the patients pulse corresponds to the induced QRS complexes – ‘mechanical capture’
• Seek senior help and definitive management

Note you can touch the patient during.