Intraoperative Oxygen Practices in Cardiac Surgery: A National Survey.

OBJECTIVE: To describe the current nationwide perspectives and practice regarding intraoperative oxygen titration in cardiac surgery. DESIGN: Prospective, observational survey. SETTING: Hospitals across the United States. PARTICIPANTS: Cardiovascular anesthesiologists and perfusionists. INTERVENTIONS: Expert- and consensus-derived electronic surveys were sent to perfusionists and cardiac anesthesiologists to evaluate the current intraoperative practices around oxygen administration. Providers were asked about individual intraoperative oxygen titration practices used at different stages of cardiac surgical procedures. Anonymous responses were collected in the Research Electronic Data Capture (REDCap). MEASUREMENTS AND MAIN RESULTS: A total of 3,335 providers were invited to participate, of whom 554 (317 anesthesiologists and 237 perfusionists) were included in the final analysis (17% response rate). During cardiopulmonary bypass (CPB), perfusionists reported a median (interquartile range [IQR]) target range from 150 (110-220)-to-325 mmHg (250-400), while anesthesiologists reported a significantly lower target range from 90 (70-150)-to-250 mmHg (158-400) (p values <0.0001 and 0.02, respectively). This difference was most pronounced at lower partial pressure of arterial oxygen (PaO2) ranges. The median PaO2 considered "too low" by perfusionists was 100 mmHg (IQR 80-125), whereas it was 60 mmHg (IQR 60-75) for anesthesiologists, who reported for both off and on bypass. The median PaO2 considered "too high" was 375 mmHg (IQR 300-400) for perfusionists and 300 mmHg (IQR 200-400) for anesthesiologists. Anesthesiologists, therefore, reported more comfort with significantly lower PaO2 values (p < 0.0001), and considered a higher PaO2 value less desirable compared with perfusionists (p < 0.0001). CONCLUSIONS: This survey demonstrated there was wide variation in oxygen administration practices between perfusionists and anesthesiologists. Hyperoxygenation was more common while on CPB.

Minimizing Ischemia Reperfusion Injury in Xenotransplantation.

The recent dramatic advances in preventing "initial xenograft dysfunction" in pig-to-non-human primate heart transplantation achieved by minimizing ischemia suggests that ischemia reperfusion injury (IRI) plays an important role in cardiac xenotransplantation. Here we review the molecular, cellular, and immune mechanisms that characterize IRI and associated "primary graft dysfunction" in allotransplantation and consider how they correspond with "xeno-associated" injury mechanisms. Based on this analysis, we describe potential genetic modifications as well as novel technical strategies that may minimize IRI for heart and other organ xenografts and which could facilitate safe and effective clinical xenotransplantation.