Surgical extraction after thrombosis around the Avalon dual lumen cannula

Long-Term Venovenous Connection for Extracorporeal Carbon Dioxide Removal (ECCO2R)-Numerical Investigation of the Connection to the Common Iliac Veins

Purpose

Currently used cannulae for extracorporeal carbon dioxide removal (ECCO₂R) are associated with complications such as thrombosis and distal limb ischemia, especially for long-term use. We hypothesize that the risk of these complications is reducible by attaching hemodynamically optimized grafts to the patient’s vessels. In this study, as a first step towards a long-term stable ECCO₂R connection, we investigated the feasibility of a venovenous connection to the common iliac veins. To ensure its applicability, the drainage of reinfused blood (recirculation) and high wall shear stress (WSS) must be avoided.

Methods

A reference model was selected for computational fluid dynamics, on the basis of the analysis of imaging data. Initially, a sensitivity analysis regarding recirculation was conducted using as variables: blood flow, the distance of drainage and return to the iliocaval junction, as well as the diameter and position of the grafts. Subsequently, the connection was optimized regarding recirculation and the WSS was evaluated. We validated the simulations in a silicone model traversed by dyed fluid.

Results

The simulations were in good agreement with the validation measurements (mean deviation 1.64%). The recirculation ranged from 32.1 to 0%. The maximum WSS did not exceed 5.57 Pa. The position and diameter of the return graft show the highest influence on recirculation. A correlation was ascertained between recirculation and WSS. Overall, an inflow jet directed at a vessel wall entails not only high WSS, but also a flow separation and thereby an increased recirculation. Therefore, return grafts aligned to the vena cava are crucial.

Conclusion

In conclusion, a connection without recirculation could be feasible and therefore provides a promising option for a long-term ECCO₂R connection.

Extracorporeal life support in the emergency department: A narrative review for the emergency physician

BACKGROUND

Extracorporeal life support (ECLS) describes the use of blood perfusion devices to provide advanced cardiac or respiratory support. Advances in percutaneous vascular cannula insertion, centrifugal pump technologies, and the miniaturization of extracorporeal devices have simplified ECLS. The intention of this discussion is to review the role of ECLS as a potential rescue method for emergency department (ED) clinicians in critical clinical scenarios and to focus on the prerequisites for managing an ECLS program in an ED setting.

DISCUSSION

Possible indications for ECLS cannulation in the ED include ongoing circulatory arrest, shock or refractory hypoxemia and pulmonary embolism with refractory shock. Severe trauma, foreign body obstruction, hypothermia and near drowning are situations in which patients may potentially benefit from ECLS. Early stabilization in the ED can provide a time window for a diagnostic workup and/or urgent procedures, including percutaneous coronary intervention, rewarming or damage control surgery in trauma. The use of ECLS is resource intensive and can be associated with a high risk of complications, especially when performed without previous training. Therefore, ECLS should only be used when the underlying problem is potentially reversible, and the resources are available to address the etiology of organ dysfunction.

CONCLUSION

Emergent ECLS has a role in the ED for selected indications in the face of life-threatening conditions. ECLS provides a bridge to recovery, definitive therapy, intervention or surgery. ECLS program requires an appropriately trained staff (physicians, nurses and ECLS specialists), equipment resources and logistical planning.

Extracorporeal respiratory support in adult patients

In patients with severe respiratory failure, either hypoxemic or hypercapnic, life support with mechanical ventilation alone can be insufficient to meet their needs, especially if one tries to avoid ventilator settings that can cause injury to the lungs. In those patients, extracorporeal membrane oxygenation (ECMO), which is also very effective in removing carbon dioxide from the blood, can provide life support, allowing the application of protective lung ventilation. In this review article, we aim to explore some of the most relevant aspects of using ECMO for respiratory support. We discuss the history of respiratory support using ECMO in adults, as well as the clinical evidence; costs; indications; installation of the equipment; ventilator settings; daily care of the patient and the system; common troubleshooting; weaning; and discontinuation.