CO2 Subcutaneous Emphysema
- Occurs with insufflation of the extraperitoneal space. May be accidental or intentional.
- Signs: Elevated ETCO2 after initial plateau, crepitus
- Treatment: Stop peritoneal insufflation. Once hypercapnia has been resolved, laparoscopy may resume with lower insufflation pressures. The presence of cervical crepitus is not a contraindication for extubation.
- Occurs when there exists a communication between the peritoneum and thorax allowing movement of gas during insufflation. This mechanism can also cause pneumomediastinum and pneumopericardium. A capnothorax is a pneumothorax via CO2.
- Signs: decreased SpO2, increased airway pressures, elevated PETCO2 in capnothorax, decreased PETCO2 in pneumothorax, decreased air movement, hyperresonance
- Treatment: Thoracocentesis or chest tube. If caused by CO2 or N2O and there is no pulmonary trauma, will resolve in 30-60 minutes without thoracentesis. PEEP may be used in cases of capnothorax. Do not use PEEP if pneumothorax is secondary to ruptured bullae.
- Occurs when pneumoperitoneum displaces the diaphragm and thus causes cephalad movement of the carina. Associated with head down position.
- Signs: decreased SpO2, increased plateau pressures, reduced air movement
- Occurs when gas is injected intravascularly or into an organ via needle or trocar. Rare complication. CO2 is more soluble and has a more rapid elimination compared to air, oxygen, and N2O.
- Pathophysiology: Causes obstruction in the vena cava and right atrium leading to decrease cardiac output and possible circulatory collapse. Increase in dead space and hypoxemia leads to V/Q mismatch.
- Signs: Dependent upon volume of gas embolized. Signs can range from mild hypotension to cardiovascular collapse. Decreased SpO2, decreased ETCO2, “millwheel murmur”, tachycardia, hypotension, arrhythmias, cyanosis, increased CVP
- Treatment: Stop peritoneal insufflation and desufflate immediately, position patient head down and in left lateral decubitus, hyperventilate with 100% FiO2. If not effective, consider aspiration of embolus from a central line. For massive embolism, CPR/ACLS and ultimately cardiopulmonary bypass may be needed. In gases of possible cerebral embolism, hyperbaric oxygen may be used.
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