Goal-Directed Perfusion Methodology for Determining Oxygenator Performance during Clinical Cardiopulmonary Bypass

Abstract

New generation oxygenators incorporate arterial line filtration either sequential to, or directly in, the gas exchange module. This unique design may affect gas exchange performance by altering the operational characteristics of the device. The present study was designed to evaluate three oxygenators in a clinical setting using a goal-directed perfusion algorithm during cardiopulmonary bypass (CPB). After institutional review board approval, 60 adult patients undergoing cardiac surgery for acquired heart disease were matched for disease state and body size into three groups based on oxygenator type: Terumo SX18™(n= 20), Terumo FX15™(n= 20), and LivaNova Inspire6F™6 Dual (n= 20). An external arterial line filter was used with the FX15, whereas the SX18 and Inspire6F had integrated arterial filters. All perfusion, anesthetic and postoperative care management was standardized using institutional goal-directed patient management processes. Data were collected and stored according to quality improvement guidelines. There were no differences in demographics or type of surgical procedure performed among groups. The Inspire6F patients required lower fraction of inspired oxygen values as compared to the SX18 (67.9% ± 6.2% vs. 75.4% ± 6.5%,p< .005) and FX15 (79.1% ± 8.4%,p< .0001) groups. Arterial oxygen content and oxygen delivery were slightly higher in the FX15 group as compared to SX18 (13.1 ± 1.4 mL O2/dL vs. 12.4 ± 1.1 mL O2/dL, 611.1 ± 150.4 mL O2vs. 528.2 ± 102.3 mL O2,p< .05). The FX15 patients had significantly higher CPB hematocrits compared to SX18 patients (30.3% ± 3.9% vs. 27.7% ± 2.6%,p< .05), but were not different when compared to the Inspire6F group (28.8% ± 3.5%,p< .50). There were no differences in intraoperative transfusion rates, but a higher percent of patients received postoperative transfusions in the SX18 group as compared to either FX15 or Inspire6F groups (p< .039). There were no differences in postoperative morbidity or complications in any group. In conclusion, the use of the SX18 was comparable to newer generation oxygenators in regard to gas exchange performance and the degree of hemodilution.