Transient venous air embolism after ERCP: worrisome or not?

A 77-year-old man was admitted for endoscopic treatment of common bile duct stones with no signs of cholangitis, after laparoscopic cholecystectomy was performed uneventfully in another hospital. At endoscopic retrograde cholangiopancreatography (ERCP) performed with CO2 insufflation under deep sedation, the bile duct was easily cannulated using the standard sphincterotome-guidewire technique. The cholangiogram revealed two 8-mm stones (Fig. 1), and subsequently a 10-mm sphincterotomy was performed with minimal bleeding, followed by stone removal with an 11.5-mm extraction balloon. Control passage showed a clear bile duct with no apparent signs of intra-procedural adverse events (Fig. 2).

Fig. 1.

Fig. 2.

A few hours after the procedure the patient developed progressive upper abdominal pain, vomiting, and became hypotensive and tachycardic with poor response to i.v. fluids. The 6-hour post-procedural laboratory studies showed an increased lipase level (193 U/L, normal <60) and a minimal inflammatory response (leukocytosis 14,470/μL, C-reactive protein 14.8 mg/L vs. 10.7 pre-procedurally), raising the initial diagnostic suspicion of post-procedural acute pancreatitis. The abdominal ultrasound performed 12 hours after the procedure for persistent symptoms revealed small echogenic particles floating within the portal vein and the inferior vena cava, which were also noted in the liver parenchyma (Video 1 – available at www.jultrason.pl, Fig. 3).

Fig. 3.

The patient was transferred to the intensive care unit for stabilization. A second ultrasound examination performed 8 hours later revealed a marked reduction in the number of microbubbles (Video 2 – available at www.jultrason.pl), while computed tomography performed 4 hours afterwards showed massive retropneumoperitoneum (Fig. 4), though the intrahepatic portal venous gas was no longer visible. Surgical intervention was performed on an emergency basis with debridement and multiple drainage of the retroperitoneal cavity (Fig. 5). The patient’s condition improved slowly, and he was discharged 4 weeks later.

Fig. 4.

Fig. 5.

The described anomalies are consistent with the presence of venous air embolism (both portal and systemic). Typical ultrasonographic features are represented by small highly echogenic particles flowing within the vessel lumen, as shown in the videos. In the case of hepatic portal venous embolism, ill-defined, highly echogenic, non-shadowing foci and spots are also present within the hepatic parenchyma, mostly in the non-dependent part, and represent features that are important in the differentiation from pneumobilia. When systemic, it may impact cardiac function and determine persistent hypotension, as in the presented case.

Venous embolism is a rare complication of ERCP, with only few cases reported so far, usually with good outcomes. It can be associated with the more frequently encountered post-ERCP complications pancreatitis⁽¹⁾ or cholangitis⁽²⁾. However, it can also be noted with perforation, when surgical exploration is usually necessary⁽³⁾. Its sometimes-transient nature^(4,5) strengthens the rationale for early transabdominal ultrasound, since its presence could be able to herald major post-procedural complications.