During laparoscopic surgery a patient develops a sudden rise in end-tidal CO₂ to 62 mmHg with haemodynamic instability. After ruling out CO₂ embolism, what is the next most likely cause of hypercarbia?
- A Pneumothorax from trocar injury
- B Malignant hyperthermia
- C Endobronchial intubation
- D Systemic absorption of insufflated CO₂ through the peritoneum ✓
Explanation
Transperitoneal absorption of insufflated CO₂ is the most common cause of hypercarbia during laparoscopy, typically manageable by increasing minute ventilation by 10–25%. Severe or unexpected hypercarbia disproportionate to insufflation may suggest inadvertent subcutaneous/retroperitoneal CO₂ tracking or CO₂ embolism. Malignant hyperthermia also causes rising EtCO₂ but is associated with rigidity, hyperthermia, and masseter spasm. Pneumothorax causes haemodynamic collapse with deviated trachea. Endobronchial intubation causes hypoxaemia and asymmetric breath sounds rather than isolated hypercarbia.
Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.
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