Carbon dioxide angiography during angioembolization for trauma patients increases the detection of active bleeding and leads to reliable hemostasis: a retrospective, observational study.

BACKGROUND: Angiography with carbon dioxide (CO2) has long been used as an alternative when iodine contrast media (ICM) cannot be used due to allergy to iodine or renal dysfunction. Conversely, CO2 angiography is also known as a provocation method for active bleeding. In this study, we examined the efficacy of CO2 angiography in angioembolization (AE) for trauma patients. METHODS: This was a single-center, retrospective, observational study of trauma patients who underwent AE at our facility between January 2012 and April 2023. RESULTS: Within this period, 335 AEs were performed. CO2 angiography was performed in 102 patients (30.4%), and in 113 procedures. CO2angiography was used to provoke active bleeding which went undetected using ICM in 83 procedures, and to confirm hemostasis after embolization in 30 procedures. Of the 80 procedures wherein, active bleeding was not detected on ICM, 35 procedures (43.8%) were detected using CO2. The spleen had the highest detection rate of active bleeding by CO2 angiography among the organs. There were 4/102 (1.9%) patients with CO2 contrast who underwent some form of reintervention. Two patients were re-embolized with n-butyl-2-cyanoacrylate because of recanalization after embolization with gelatin sponge. The other two patients had pseudoaneurysm formation which required reintervention, and CO2 angiography was not used. Vomiting was the most common complication of CO2 angiography in 10 patients (9.8%), whereas all were transient and did not require treatment. CONCLUSIONS: CO2 angiography of trauma patients may have a better detection rate of active bleeding compared with ICM, leading to reliable hemostasis.

Severe liver injury successfully treated with transarterial embolization using carbon dioxide angiography: A case report.

Angiography using carbon dioxide (CO2) has gained attention as a method of inducing active bleeding in patients for whom bleeding cannot be detected with iodine contrast medium (ICM). We experienced a case in which CO2 angiography was performed during transarterial embolization (TAE) for severe liver injury with active bleeding. A woman in her 40s was struck by a minitruck while crossing the road and rushed to our hospital. Upon admission, she was in shock vital with blood pressure of 75/38 mmHg and pulse rate of 130 bpm. Blood transfusion was promptly started after arrival and her blood pressure increased. Abdominal ultrasonography showed echo free space in Morrison's pouch. Contrast-enhanced CT showed deep liver laceration in the right lobe and intra-abdominal hemorrhage with active bleeding. We selected TAE for hemostasis. ICM angiography showed extravasation of contrast medium from the anterior and posterior segmental branches, which was embolized with a gelatin sponge. After embolization, CO2 angiography revealed new extravasation that could not be detected by ICM, which was additionally embolized. There was no rebleeding or pseudoaneurysm after embolization. In TAE for deep liver injury, ICM alone may underestimate active bleeding. CO2 angiography may lead to better outcomes when injured vessels are reliably identified and TAE is performed.

Unveiling the cell dynamics during the final shape formation of the tarsus in Drosophila adult leg by live imaging.

Organisms display a remarkable diversity in their shapes. Although substantial progress has been made in unraveling the mechanisms that govern cell fate determination during development, the mechanisms by which fate-determined cells give rise to the final shapes of organisms remain largely unknown. This study describes in detail the process of the final shape formation of the tarsus, which is near the distal tip of the adult leg, during the pupal stage in Drosophila melanogaster. Days-long live imaging revealed unexpectedly complicated cellular dynamics. The epithelial cells transiently form the intriguing structure, which we named the Parthenon-like structure. The basal surface of the epithelial cells and localization of the basement membrane protein initially show a mesh-like structure and rapidly shrink into the membranous structure during the formation and disappearance of the Parthenon-like structure. Furthermore, macrophage-like cells are observed moving around actively in the Parthenon-like structure and engulfing epithelial cells. The findings in this research are expected to significantly contribute to our understanding of the mechanisms involved in shaping the final structure of the adult tarsus.

In vitro comparison of the leakage of carbon dioxide and iodine contrast media in a bleeding model.

BACKGROUND: We aimed to compare the hydrodynamic values of carbon dioxide (CO2) and iodine contrast media for bleeding detection using an in vitro model. MATERIALS AND METHODS: We created a bleeding model with large and small wounds in simulated blood vessels. We connected a syringe to the bleeding model and the blood pressure transducer, filling the circuit with CO2 and iodine contrast media. The syringe's piston was pressed, and the flow rate and intravascular pressure of the CO2 and iodine contrast media leaking from the bleeding model were measured. We compared each leaked contrast medium's volume, sphere-equivalent diameter, and sphere-equivalent area. These values were analyzed to compare the visibility of the leakage objectively. RESULTS: At a constant flow rate, the intravascular pressure required for the model to leak was lower for the CO2 than that for the iodine contrast medium. The CO2 contrast medium leakage volume, equivalent circle diameter, and equivalent circle area were greater than those of the iodine one. These values indicate higher CO2 visibility during fluoroscopy. CONCLUSIONS: In the bleeding model, a CO2 contrast medium may be more prone to leakage than the iodine one in large and small wounds. Regarding visibility, a CO2 contrast medium may be more likely to detect leakage than an iodine one.