Immunofluorescence Protocol for Characterization of Platelet and Leukocyte Binding in Extracorporeal Membrane Oxygenation (ECMO) Circuits.

The continuous contact between blood and the foreign surface of the extracorporeal membrane oxygenation (ECMO) circuit contributes to hemostatic, inflammatory, and other physiological disturbances observed during ECMO. Although previous studies have extensively investigated blood samples from patients on ECMO, cell adsorption to the ECMO circuit as an additional factor that could potentially influence clinical outcomes, has largely been overlooked. Here we provide a detailed immunofluorescence (IF) protocol designed to characterize cellular binding on ECMO circuits collected from patients. Extracorporeal membrane oxygenation circuits were collected from three pediatric patients and an albumin primed-only ECMO circuit was used as control. Circuit samples from five different sites within each ECMO circuit were collected and processed for the IF protocol. CD14 and CD42a antibodies were used to identify platelets and leukocytes bound to each ECMO circuit sample and images captured using inverted fluorescence microscopy. The protocol enables the comprehensive characterization of platelet and leukocyte binding to ECMO circuits collected from patients, which could in turn extend our knowledge of the characteristics of circuit binding and may provide guidance for improved ECMO circuit design.

The Safe Addition of Nitric Oxide into the Sweep Gas of the Extracorporeal Circuit during Cardiopulmonary Bypass and Extracorporeal Life Support.

Low cardiac output syndrome and the systemic inflammatory response are consequences of the cardiac surgical perioperative course. The mechanisms responsible are multifactorial, but recent studies have shown that nitric oxide (NO) may be a key component in mitigating some of these processes. Following on from literature reports detailing the use of inhaled NO added to the gas phase of the extracorporeal circuit, we set about developing a technique to perform this addition safely and efficiently. In the setting of cardiopulmonary bypass, the technique was validated in a randomized prospective trial looking at 198 children. The benefits observed in this trial then stimulated the incorporation of NO into all extracorporeal life support (ECLS) circuits. This required additional hardware modifications all of which were able to be performed safely. Initial results from the first series of ECLS patients using NO also appear promising.