Laparoscopy: Resp complications

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.

Pneumothorax

• 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.

Endobronchial Intubation

• 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

Gas Embolism

• 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.