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.

Integrated Oxygenator FX05.

In recent years, there has been a trend to incorporate arterial filters into cardiopulmonary bypass (CPB) oxygenators. The FX oxygenators are the first examples of integrating a filter around the fibers of the oxygenator. To assess the efficacy of the FX05 oxygenator, in comparison with our existing CPB setup (RX05 oxygenator + arterial filter), we randomly assigned 40 patients undergoing CPB, with calculated flows <1.5 L/min, to FX05 or RX05 + arterial filter (19 FX and 21 RX). Embolic load was assessed using the emboli detection and classification quantifier, with sensors placed prefilter and postfilter/oxygenator at identical distances for both devices. A total of 6,270 FX readings and 6,183 RX readings were obtained. Because of the extremely skewed nature of the data, the prefilter embolic volumes were divided into deciles, and each decile was analyzed separately. Our results show that the devices perform similarly; both filter out a high percentage of the prefilter embolic load. Our data support that in the clinical setting, the FX05 is as effective at removing emboli as the RX05 with an arterial filter (CXAF02) which, in conjunction with the prime volume reduction and circuit simplification, has warranted our conversion to the FX series of oxygenators.

Centrifugal pump inlet pressure site affects measurement.

During extracorporeal life support (ECLS), blood is exposed to a myriad of unphysiological factors that can affect outcome. One aspect of this is the sub-atmospheric pressure generated by the ECLS pump and imparted to blood elements along the pump inlet line. This pressure can be measured on the inlet line close to the pump head by adding a connector, or at the venous cannula connection site. We compared the two measurement sites located at both points; between the venous cannula-inlet tubing and inlet tubing-pump, with a range of cannulae and flows. We also investigated the effects on inlet pressure from pump afterload and increasing inlet tubing length.