The PEA arrest and the reversible cause

Confirm the arrest, call for the arrest team, and begin high-quality CPR — compressions at 100 to 120 per minute to 5 to 6 cm with full recoil and minimal interruption, the airway managed and 100 per cent oxygen given, and intraosseous or intravenous access secured. As PEA is non-shockable, no shock is given; adrenaline 1 milligram is given every three to five minutes (every cycle), and the rhythm is rechecked every two minutes.^[2]

The defining task in the PEA arrest is the search for a reversible cause, because PEA is almost always the electrical manifestation of a mechanical problem — a tamponade, a tension pneumothorax, a massive thrombosis, hypovolaemia, or a toxin. The four Hs and four Ts are worked through systematically, and the bedside ultrasound, run during the rhythm check without interrupting the compressions, is the highest-yield tool: a focused cardiac view identifies a pericardial effusion (tamponade) or a dilated right ventricle (massive pulmonary embolism); the lung views identify a pneumothorax; and the assessment of the venous volume and the contractility distinguishes hypovolaemia and pump failure.^[3]

The context — recent major orthopaedic surgery — makes a massive pulmonary embolism or a haemorrhagic cause the leading differential. If the focused cardiac ultrasound shows a dilated right ventricle, or the history and the early blood gas support a thrombotic cause, a thrombolytic is given for the presumed pulmonary embolism and the CPR is continued for up to an hour with the reversible-cause treated. If a tamponade is found it is drained; a tension pneumothorax is decompressed; hypovolaemia is treated with fluid or blood. The resuscitation is led as a team with allocated roles, the reversible cause is revisited at every cycle, and the patient who regains a pulse is managed in the post-ROSC bundle.^[1]