Novel and highly reliable leak check tests for drop- and external pressure-type cell-free and concentrated ascites reinfusion therapy.

INTRODUCTION: For safe management of cell-free and concentrated ascites reinfusion therapy (CART), a highly reliable leak test for detecting ascites filter damage is essential. However, such a test has not been established for drop-type CART. METHODS: We devised two novel leak tests for drop- and external pressure-type CART, manual or pump pressurization methods, using high-pressure loading and pressure monitoring, and investigated their reliability. RESULTS: Both methods could easily load and maintain sufficiently high pressure (>400 Torr) on the hollow fibers for 2 min. No result deviation was noted between different operators. The pressure drops in both methods were identical and significantly lower than those in the leak test using a special CART machine, the e-CART. CONCLUSION: The reliability of our revised leak test is equivalent to that of the automatic leak test of e-CART. These highly reliable leak tests may contribute to safety in patients undergoing drop- and external pressure-type CART.

Hemolytic characteristics of three suctioning systems for use with a newly developed cardiopulmonary bypass system.

INTRODUCTION: We have been developing a closed-circuit cardiopulmonary bypass (CPB) system ("Dihead CPB") for application during coronary artery bypass grafting (CABG) and valve surgery. To strive for minimal hemolysis during Dihead CPB, we compared the hemolysis caused by three different suction systems and performed a clinical study with the newly applied suction system. MATERIALS & METHODS: We evaluated the hemolysis caused by roller-pump suction, the SmartSuction® Harmony® and wall suction systems with respect to suction speed and compared the systems by means of in vitro studies. A clinical study was also performed on 15 volunteers to assess hemolysis and the adequacy of the newly applied suction system with Dihead CPB. RESULTS: Pressure inside the suction cannula was -22.5 ± 0.1 mmHg at a maximum flow of 1.5 L/min for roller-pump suction and -43.4 ± 0.1 mmHg at -150 mmHg of the set vacuum pressure of wall suction. With the SmartSuction, the pressure inside the cannula varied from -76.3 ± 1.0 to -130.3 ± 1.5 mmHg, depending on suctioning conditions. Suction speed (to suction 50 ml of blood) was fastest with the SmartSuction (69.7 ± 3.58 s) whereas, with roller suction, it was 117.3 ± 8.47 s and with wall suction 96.9 ± 7.10 s. The SmartSuction had the highest hemolysis rate (2.00 ± 0.33%) vs. 0.61 ± 0.10% for roller suction and 0.41 ± 0.11% for wall suction (p<0.001). The clinical study with wall suction showed no significant increase in plasma free hemoglobin during or after CPB compared with before surgery. CONCLUSIONS: Wall suction had less hemolysis than roller suction or the SmartSuction in the in vitro study and the clinical study with wall suction showed efficient suction speed and acceptable hemolysis, suggesting that Dihead CPB with wall suction is feasible for CABG.