Makindo Medical Notes

💨 Carbon Dioxide (CO₂) Embolism is a rare but life-threatening complication of laparoscopic surgery. It occurs when insufflation gas enters the venous circulation, obstructing right heart outflow and causing sudden haemodynamic collapse. Early recognition and rapid management are critical to survival. 🚨

🧾 About

• Occurs during laparoscopic surgery, when CO₂ is used to create pneumoperitoneum.
• CO₂ emboli obstruct venous return and right ventricular outflow → obstructive shock.
• Most dangerous if large vessels or solid organs (e.g. liver in bariatric surgery) are punctured during trocar/needle placement.

⚠️ Aetiology / Risk Factors

• Incorrect needle/trocar placement into a vessel or parenchymal organ.
• Enlarged organs (e.g. hepatomegaly in obesity) increase risk of vessel puncture.
• High insufflation pressures or rapid insufflation.
• CO₂ preferred for pneumoperitoneum (non-flammable, cheap, rapidly absorbed) but still dangerous if intravascular.

🩺 Clinical Features

• Sudden ↓ End-tidal CO₂ (EtCO₂) – classic, but paradoxical ↑ EtCO₂ can occur due to increased absorption.
• Hypotension, tachycardia → cardiovascular collapse.
• “Mill-wheel murmur” – splashing cardiac murmur heard over precordium (rare but diagnostic).
• Hypoxia, arrhythmias, and cardiac arrest may follow.
• Possible haemorrhage if a vessel was punctured.

🔎 Investigations / Diagnosis

• Diagnosis is primarily intraoperative and clinical (sudden collapse after insufflation).
• TOE (transoesophageal echocardiography) – most sensitive test for detecting intravascular gas.
• Precordial Doppler may detect gas bubbles early (used in high-risk cases).

🧪 Pathophysiology

• Gas embolus → obstructs right atrium/ventricle and pulmonary arteries → ↓ pulmonary flow + ↑ pulmonary artery pressure.
• Causes acute right heart failure, systemic hypotension, arrhythmia, and potential cardiac arrest.
• Risk of paradoxical embolus if PFO present → stroke/MI/systemic emboli.
• Compared to air embolism: CO₂ is more soluble → potentially less pulmonary injury, but still rapidly fatal in large volume entry.

💊 Management

• 🚨 Immediate Actions:
  • Stop insufflation & deflate abdomen.
  • 100% Oxygen (discontinue N₂O).
  • Call for help, alert surgical and anaesthetic team.
• 🔄 Supportive:
  • IV fluid bolus → ↑ central venous pressure, limit further embolus entry.
  • Vasopressors/inotropes as required.
• 📍 Positioning:
  • Durant’s manoeuvre: left lateral decubitus + Trendelenburg → traps embolus in right atrial apex.
• 💉 Other measures:
  • Aspiration of gas if central line present.
  • Consider ECMO or hyperbaric oxygen in severe/refractory cases.
• 🫀 ALS protocol if cardiac arrest.

📊 Prognosis

• Small emboli may resolve rapidly as CO₂ is absorbed.
• Large emboli can be fatal within minutes if not promptly recognised and treated.
• Outcome depends on speed of diagnosis and resuscitation.

📚 References

• Park EY, Kwon JY, Kim KJ. Carbon dioxide embolism during laparoscopic surgery. Yonsei Med J. 2012;53(3):459-466.
• AAGBI Safety Guideline: Management of gas embolism in anaesthesia.