1. Monitor vitals, ECG at all times.

2. Prep xiphoid and below and give LA (if time allows)

3. 16-18g angicath attached to large syringe with 3-way stop-cock. 

4. Assess if large mediastinal shift has moved the heart.  Puncture skin 1-2cm inferiorly to xiphocondral junction, 45o to skin.  Advance needle cephalad toward tip of left scapula.

5. If adanced into heart, extreme ST-T waves or wide/large QRS complexes are seen ("current of injury").  Withdraw until previous trace apears.  Prem beats may also occur.

6. When tip enters bld filled sac, aspirate as much blood as possible.  The heart expands more --> current of injury may apear.  Withdraw slightly.  If persisting, withdraw needle completely.

7. When finished, remove syringe attach a 3 way stopcock, leaving it closed.  Secure into place.  Could also apply the Seldinger technique with flexy guidewire through needle and a 14g catheter over the top.

8.  If tamponade persists, open stopcock and reaspirate sack.  Suture or tape a plastic pericardiocentesis catheter into place with a small dressing for continued decompression en route to definitive surgery / elsewhere.  All pts requiring pericardiocentesis require sternotomy.

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Complications

Getting ventricular blood, not pericardial blood.
Lacerating myocardium or a coronary vessel.
New haemopericardium (though myocardium is usually self-sealing)
VF
Pneumothorax
Great vessel puncture & worse tamponade.
Oesophageal puncture & mediastinitis
Peritoneal puncture with peritonitis.

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