Seesawing end-tidal carbon dioxide: portent of critical carbon dioxide embolism in retroperitoneoscopy

An abrupt increase in end-tidal CO₂ (EtCO₂; from 35 to 58 mm Hg) followed by a sudden fall (to 18 mm Hg) was noted during retroperitoneoscopic adrenalectomy under general anaesthesia in a 23-year-old patient with adrenal hyperplasia. This was accompanied by hypotension (systolic blood pressure of 60 mm Hg), desaturation (88% SpO2) and ST depression (3.5 mm). The patient was resuscitated with fluids and vasopressor drugs and about 4 mL of air was aspirated through the central venous catheter, confirming the diagnosis of an intraoperative gas embolism. Later, a rent in the adrenal vein extending into the inferior vena cava was discovered and sutured. The blood pressure, EtCO₂, ST segment and pulse oximetry returned to normal after 15 min. This case demonstrates that gas embolism may transpire during retroperitoneoscopic adrenalectomy and an acute rise followed by a sharp fall in EtCO₂ should alert the anaesthesiologist to this rare but potentially fatal complication.