Carbon Dioxide Embolism During Laparoscopy

Carbon dioxide (CO2) embolism during laparoscopy is entry of insufflated carbon dioxide into the venous circulation, occurring during insufflation, at trocar placement, or when a vessel is injured. Gas embolism may be small and silent or cause collapse.

Epidemiology. Subclinical embolism occurs in up to 17% of laparoscopic cholecystectomies by transoesophageal echocardiography, and clinically significant embolism in about 0.001% to 0.6%. Risk is highest at the start of insufflation (Veress needle in vein or solid organ) and in hysteroscopy and hepatic surgery.

Risk factors. Direct needle injection into vessel, high insufflation pressure (over 15 mmHg), head up position, open venous sinuses, hepatic resection, hypovolaemia and hysteroscopy.

Pathophysiology.

Carbon dioxide is 20 times more soluble than air, so it dissolves in blood, which makes lethal embolism less likely but still possible with volumes of 0.5 to 1 mL/kg. A gas lock forms in the right ventricle, with pulmonary hypertension, reduced output and ventilation perfusion mismatch. Carbon dioxide absorption can first raise end tidal values.

Transient rise then abrupt fall in end tidal carbon dioxide, hypotension, arrhythmia, hypoxaemia, raised central venous pressure, mill wheel murmur and cyanosis.

Red flags.

• Abrupt end tidal carbon dioxide fall with hypotension.
• Hypoxaemia and rising pulmonary pressure.
• Cardiac arrest.

Transoesophageal echocardiography is the reference. Precordial Doppler and capnography are practical. Blood gas shows hypoxaemia and acidosis. Differentiate from other causes of collapse.

Differential diagnosis.

• Tension pneumothorax.
• Haemorrhage.
• Pulmonary embolism.
• Vagal reflex from insufflation.
• Anaphylaxis.
• Cardiac event.

Stop insufflation and desufflate the abdomen at once. Give 100% oxygen, stop nitrous oxide, and lay the patient in the left lateral head down position if feasible. Aspirate gas via a central line if one is present.

• Fluids: crystalloid 500 mL to 1 L rapidly to increase venous pressure.
• Adrenaline: 10 to 100 microgram IV, then 0.02 to 0.2 microgram/kg/min; monitor arterial pressure and ECG; avoid excess in ischaemia.
• Noradrenaline: 0.05 to 0.5 microgram/kg/min; maximum 1 microgram/kg/min.
• Start chest compressions for arrest.

Hyperventilate after resuscitation to clear carbon dioxide. Restart the laparoscopy after recovery with lower pressure (8 to 12 mmHg) or convert to open surgery. Extracorporeal support in refractory arrest.

Prevention. Confirm Veress needle position with a saline drop test, use open (Hasson) technique in high risk patients, keep intra-abdominal pressure under 15 mmHg, and monitor capnography.

Monitoring. End tidal carbon dioxide, ECG, arterial pressure and saturation until stable for 30 minutes.

Referral and escalation. Senior anaesthetic and critical care.