Development of fatal systemic gas embolism during direct peroral cholangioscopy under carbon dioxide insufflation

Direct peroral cholangioscopy (DPOCS) is a useful and effective technique for diagnosis and therapy of biliary tract disease [1] [2] [3]. No instances of a fatal systemic gas embolism developing during DPOCS under carbon dioxide (CO₂) insufflation have yet been reported.

A 68-year-old woman was admitted to our hospital with a complaint of hepatolithiasis ([Fig. 1]). She had undergone Roux-en-Y hepaticojejunostomy for choledochal cysts 34 years previously. We performed DPOCS using a short-type double-balloon enteroscope (DBE), an ultraslim endoscope, and an endoscopic CO₂ regulator (EC-450BI5, EG-580NW, GW-1, respectively; Fujifilm Corp., Tokyo, Japan) while the patient was kept adequately sedated with midazolam.

Fig. 1 Images of a hepatolith (white arrow), 20 mm in diameter, in the left intrahepatic bile duct on: a computed tomography (CT) scan; b magnetic resonance cholangiopancreatography (MRCP).

We planned to perform lithotripsy of the hepatolith using a Holmium:YAG laser. After we had reached the anastomosis using the DBE, attempts to extract the stones through the DBE using balloon or basket catheters failed ([Fig. 2 a]). We therefore decided to perform DPOCS with an ultraslim endoscope passed through an overtube using a previously described method ([Fig. 2 b]) [3]. The balloon attached to the overtube remained inflated from the time that we reached the anastomosis until the end of the procedure.

Fig. 2 Radiographic images showing: a an attempt to extract the stones through the double-balloon enteroscope (DBE) from the distal side of the anastomosis; b an ultraslim endoscope, which had replaced the DBE, advanced into the bile duct.

We first confirmed the hepatolith was present ([Fig. 3 a]). We then prepared the Holmium:YAG laser for lithotripsy for 5 minutes, while we aspirated pus and mucus discharged from the peripheral bile duct near the hepatolith. As we fractured the hepatolith with the Holmium:YAG laser ([Fig. 3 b]), the patient suddenly went into shock and had a cardiac arrest. Despite immediate cardiomegaly resuscitation and injection of flumazenil, she died. A computed tomography (CT) scan performed during resuscitation revealed multiple gas emboli in the systemic arteries and veins ([Fig. 4]).

Fig. 3 Views via the ultraslim endoscope showing: a the hepatolith along with pus and mucus in the left intrahepatic bile duct; b the proximal bile duct beyond the hepatolith seen at the moment of lithotripsy using a Holmium:YAG laser after mucus and pus had been removed.

Fig. 4 Computed tomography (CT) scan during resuscitation showing multiple gas emboli in the systemic arteries and veins of: a the brain; b the heart.

Pathological examination later revealed hepatic abscesses, inflammation surrounding the hepatolith, intravascular gas, and systemic gas emboli [4]. There was no evidence of a patent foramen ovale [5]. The cause of death was systemic gas embolism. We believe aspiration of pus and mucus prior to lithotripsy may have opened a pre-existing biliovenous shunt.

Endoscopists should take the possibility of fatal gas embolism into consideration during DPOCS even under CO₂ insufflation. The extent of insufflation should be the absolute minimum required.

Endoscopy_UCTN_Code_CPL_1AK_2AI

Competing interests: None

• References

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