Why is carbon dioxide used for insufflation in laparoscopy?

Why Carbon Dioxide is Used for Insufflation in Laparoscopy

Carbon dioxide is the standard insufflation gas for laparoscopy because of its high solubility, rapid absorption and excretion, non-flammability, and safety with electrosurgical instruments, making it superior to alternative gases despite causing some physiologic changes. 1, 2

Primary Advantages of CO2

Safety Profile with Surgical Equipment

• CO2 is non-flammable and can be safely used with electrocautery and laser devices, which is critical since energy-based instruments are routinely used during laparoscopic procedures 3
• Air, oxygen, and nitrous oxide cannot be safely used with electrosurgical instruments due to combustion risk, severely limiting their clinical utility 3

Physiologic Properties

• CO2 has exceptionally high diffusibility and rapid absorption/excretion rates, allowing the body to clear absorbed gas efficiently through pulmonary ventilation 2
• The high solubility of CO2 means that if gas embolism occurs, it is absorbed much more rapidly than insoluble gases like helium or air, reducing embolic complications 2, 3
• CO2 provides clear, unimpeded visualization during surgery as it is colorless 3

Clinical Outcomes

• CO2 insufflation significantly reduces post-procedure pain and abdominal distension compared to air insufflation, leading to improved patient satisfaction and reduced admission rates 4, 1
• The use of CO2 has been shown to decrease hospital admissions primarily due to reduced pain without perforation when compared to air 4

Comparison with Alternative Gases

Nitrous Oxide

• Nitrous oxide pneumoperitoneum may decrease post-operative pain scores on the first post-operative day compared to CO2 in low-risk patients 5
• However, nitrous oxide poses significant safety concerns with electrosurgical instruments and its overall safety profile remains unestablished 3, 5

Helium

• Helium produces fewer cardiopulmonary changes (less respiratory acidosis) than CO2 because it is metabolically inactive and minimally absorbed 3, 5
• Despite theoretical advantages, helium has been associated with serious adverse events including subcutaneous emphysema and shows no clinical benefit over CO2 in low-risk patients 5
• Helium's lower solubility means slower clearance if absorbed and potentially greater risk if embolism occurs 3

Air and Oxygen

• Air and oxygen are contraindicated due to high risk of gas embolism and incompatibility with electrosurgery 3

Physiologic Considerations and Management

Cardiopulmonary Effects

• CO2 absorption causes respiratory acidosis with elevated PCO2 and lowered pH, which is generally well-tolerated in healthy patients 2
• Standard insufflation pressure should be maintained at 10-15 mmHg (typically 12 mmHg) to balance adequate surgical exposure while minimizing cardiovascular complications 4, 1
• In high-risk patients with cardiac or pulmonary disease, the cardiovascular effects (increased blood pressure, pulse, cardiac output, and lowered arrhythmia threshold) require careful anesthetic management 2

Intraoperative Monitoring

• Capnography should be used intraoperatively to monitor CO2 levels and avoid maternal hypo- and hypercapnia, particularly in pregnant patients 4
• The American College of Cardiology recommends maintaining the lowest possible pressures in patients with congenital heart disease, as pneumoperitoneum dramatically affects preload and pulmonary vascular resistance 6

Common Pitfalls to Avoid

• Avoid using air insufflation instead of CO2, as this significantly increases post-procedure pain and complications 4, 1
• Do not use excessively high insufflation pressures; pressures exceeding 20 mmHg indicate potential abdominal compartment syndrome and should prompt immediate evaluation 6
• Ensure complete evacuation of pneumoperitoneum before trocar removal or specimen extraction to minimize environmental contamination and reduce residual gas-related pain 4, 1
• Utilize closed-circuit smoke evacuation systems to manage surgical plume, as electrosurgical devices can aerosolize particles regardless of the insufflation gas used 4