Background High-echoic objects in the hepatic vessels of patients with cardiopulmonary arrest (CPA) are frequently detected by ultrasonography.

Objective To demonstrate this phenomenon and clarify its clinical characteristics.

Methods In a tertiary care academic medical centre, 203 CPA patients were evaluated by ultrasonography. CT determined the origin and location of high-echoic objects detected in the liver. The frequency and characteristics of this phenomenon were investigated. The background, laboratory data and survival rate were compared between patients with and without high-echoic objects.

Results High-echoic objects were seen in 73 (36.0%) patients and could clearly be detected in the hepatic veins of 41 (56.2%) patients. CT confirmed that these were gas in 27 of 53 patients, and were clearly visible in the hepatic veins in 12 (44.4%) patients. Hepatic portal venous gas was not identified. Compared to patients without high-echoic objects, witnessed arrest (p<0.001), bystander cardiopulmonary resuscitation (p=0.005), ventricular fibrillation or pulseless electrical activity (p=0.012) and return of spontaneous circulation (p=0.018) were significantly less frequent in patients with high-echoic objects. These patients had a lower incidence of survival to discharge (1.4% vs 7.7%, p=0.100). Multivariate analysis showed that absence of high-echoic objects was a marginally significant factor in association with return of spontaneous circulation (p=0.052).

Conclusions High-echoic objects were often observed on ultrasonography in CPA patients; these objects were considered hepatic venous gas. The presence of high-echoic objects may be a poor prognostic sign in patients with CPA.