START

❶ Call for help and inform theatre team of problem. Note the time.

❷ Call for cardiac arrest trolley.

❸ Stop all potential triggers. Stop surgery.

❹ Give 100% oxygen and ensure adequate ventilation:

• Maintain the airway and, if necessary, secure it with tracheal tube.

❺ If indicated start CPR immediately (CPR can help disperse air emboli and large thrombi).

❻ Give i.v. crystalloid at a high infusion rate. (Adult: 500-1000 ml, Child: 20 ml.kg^-1)

• Inotropes may be required to support circulation.

❼ Treat according to suspected embolus type (see Boxes A-D) whilst considering alternative diagnoses (Box E).

❽ Consider investigations to help confirm diagnosis:

• Arterial blood gases (increased PaCO₂-ETCO₂ gradient).
• Transoesophageal echocardiography (right heart strain, pulmonary arterial emboli).
• Computerised tomography.

❾ If cardiovascular collapse refractory to treatment, consider extra-corporeal membrane oxygenation (ECMO) or intra-aortic balloon counter-pulsation.

❿ Plan transfer of the patient to an appropriate critical care area.

Box A: THROMBOEMBOLISM

Consider thromboembolism e.g. alteplase 10 mg i.v. then 90 mg over 2 h (>65kg)

Consider surgical removal - consult vascular surgeon

Consider percutaneous removal - consult radiologist

Box B: FAT EMBOLISM

• Petechial rash, desaturation, confusion/irritability if patient conscious
• Supportive measures are mainstay of initial management

Box C: AMNIOTIC FLUID EMBOLISM

• Supportive measures are mainstay of initial management
• Monitor the fetus, if undelivered
• Treat coagulopathy (fresh frozen plasma, cryoprecipitate and/or platelets)
• Consider plasmaphoresis

Box D: AIR/GAS EMBOLISM

• "Mill wheel" murmur may be present
• Discontinue source of air/gas if applicable and discontinue N₂O
• Tell surgeon to flood wound with saline and cover with wet packs
• Lower surgical field to below level of heart if possible
• Place patient in left lateral position if possible
• If central venous catheter in situ, attempt to aspirate air
• Volume loading and Valsalva manoeuvre may help

Box E: ALTERNATIVE DIAGNOSES

• Pneumothorax (+/- tension)
• Bronchospasm (→ 3-4) 
• Pulmonary oedema
• Cardiogenic shock
• Hypovolaemia
• Myocardial failure
• Sepsis (→ 3-14)
• Bone cement implantation syndrome
• Anaphylaxis (→ 3-1)