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This study compared the quality of perfusion delivered by two oxygenators--the hollow-fiber membrane Capiox Baby RX05 and silicone membrane Medtronic 0800--using hemodynamic energy indicators. The oxygenators were tested across varying flow rates and perfusion modes in a neonatal extracorporeal life support (ECLS) model. The experimental ECLS circuit included a Jostra HL-20 heart/lung machine with Jostra Roller pump, oxygenators with associated tubing and components, and a neonatal pseudo-patient. We used a 40/60 glycerin/water solution in the circuit as a blood analog. Testing occurred at flow rates of 250, 500, and 750 mL/min at 37°C under both pulsatile and nonpulsatile flow conditions. Hemodynamic data points consisted of recording 20-s intervals of data, and a total of 96 experimental repetitions were conducted. The pressure drop across the Capiox Baby RX05 oxygenator was significantly lower than the pressure drop across the Medtronic 0800 at all flow rates and perfusion modes. Furthermore, the Medtronic 0800 oxygenator showed significantly lower post-oxygenator energy equivalent pressures, total hemodynamic energy values, and surplus hemodynamic energy retention values compared to those of the Capiox Baby RX05. These results indicate the Medtronic 0800 oxygenator significantly dampens the hemodynamic energy compared to the Capiox Baby RX05. Consequently, clinical use of the Medtronic 0800 in a pulsatile ECLS setting is likely to mitigate the benefits provided by pulsatile flow. In contrast, the Capiox Baby RX05 better transmits hemodynamic energy to the patient with much lower pressure drop.

Gaseous microemboli (GME) remain a challenge for cardiopulmonary bypass (CPB) because there is a positive correlation between microemboli exposure during CPB and postoperative neurological injury. Thus, minimizing the number of GME delivered to pediatric patients undergoing CPB procedures would lead to better clinical outcomes. In this study, we used a simulated CPB model to evaluate the effectiveness of capturing GME and the degree of membrane pressure drop for a new membrane oxygenator, Capiox Baby FX05 (Terumo Corporation,Tokyo, Japan), which has an integrated arterial filter with open and closed purge line.We used identical components in this study as our clinical CPB circuit. Three emboli detection and classification quantifier transducers were placed at prepump, preoxygenator, and postoxygenator sites in the circuit.Two flow probes as well as three pressure transducers were placed upstream and downstream of the oxygenator. The system was primed with human blood titrated to 30% hematocrit with Lactated Ringer’s solution.A bolus of air (1 mL) was injected in the prepump site under nonpulsatile perfusion mode at three flow rates (500,750, and 1000 mL/min) and with the purge line either open or closed. Six trials were performed for each unique set-up for a total of 36 trials.All trials were conducted at 35°C. The circuit pressure was kept constant at 100 mm Hg. Both the size and quantity of microemboli detected at postoxygenator site were recorded for 5 min postair injection. It was found that total counts of GME were significantly reduced with the purge line open when compared to keeping the purge line closed (P0.0001 at 1000 mL/min). At all flow rates, most of the GME were under 20 microns in size. In terms of microemboli greater than 40 microns, the counts were significantly higher with the purge line closed compared to keeping the purge line open at flow rates of 750 mL/min and 1000 mL/min (P0.01). At all flow rates,there is a tiny difference of less than 1 mmHg in membrane pressure drop between keeping the purge line open and closed, which is due to the small arteriovenous (A-V) shunt(P0.001). These results suggest that the integrated arterial filter of the Capiox FX05 oxygenator significantly improves the capturing of GME but has little impact on membrane pressure drop.

Blood cardioplegia delivery systems are employed in most pediatric open heart cases to arrest the heart and keep it preserved during aortic cross-clamping. They are also used as part of a modified ultrafiltration system at the end of cardiopulmonary bypass. We evaluated and compared the air-handling capabilities of different types of blood cardioplegia delivery devices. A simple circuit incorporating a cardiotomy reservoir, a roller pump, a cardioplegia test system, and two emboli detection and classification sensors were used to investigate the air-handling capabilities of the following cardioplegia delivery systems: GISH Vision, Maquet Plegiox, Medtronic Trillium MYOtherm XP, Sorin Group BCD Vanguard, Sorin Group CSC14, and Terumo Sarns Conducer and Bubble Trap. The 0.25-in. circuit was primed with 400mL of Lactated Ringer's. Outdated packed red blood cells were added to obtain a hematocrit of 24-28%. System pressure was maintained at 50mmHg. Air (0.1, 0.3, 0.5mL) was injected at a speed of 0.1mL/s into the circuit just after the pump head. Gaseous microemboli (GME) were measured prior to the cardioplegia system and after the device to evaluate the air-handling characteristics. The tests were run at 100, 200, and 400mL/min blood flow for both 4 and 37°C. There were no significant differences among the groups when comparing precardioplegia delivery system GME, thus demonstrating that all devices received the same amount of injected air. When comparing the groups for postcardioplegia delivery system GME, significant differences were noted especially at the 400mL/min blood flow rate. These results suggest that for the devices compared in this study, the Maquet Plegiox and the Medtronic Trillium MYOtherm XP eliminated GME the best.

A series of studies performed at our center demonstrates that gaseous microemboli (GME) remain a challenge in cardiac surgical procedures. Evaluation of novel oxygenators must address hemodynamic parameters and microemboli capture capability. The objective of this study is to compare two neonatal membrane oxygenators, the Quadrox-i (MAQUET Cardiopulmonary AG, Hirrlingen, Germany) and the Capiox RX05 (Terumo Corporation, Tokyo, Japan), with respect to GME capture and hemodynamic energy delivery. The experimental circuit included a Maquet HL-20 heart-lung machine, a Heater-Cooler Unit HCU 30 (MAQUET Cardiopulmonary AG), a membrane oxygenator (Quadrox-i Neonatal or Capiox RX05), and ¼-inch tubing from the COBE Heart/Lung Perfusion Pack (COBE Cardiovascular, Inc., Arvada, CO, USA). A Capiox cardiotomy reservoir CX*CR10NX (Terumo Corporation) acted as a pseudopatient. The circuit was primed with human packed red blood cells and lactated Ringer's solution and de-aired according to clinical priming procedure. Heparin (5000IU) was added into the circuit. The total volume was 400mL and hematocrit was 30%. Pump flow rate was maintained at 500 or 1000mL/min under both pulsatile and nonpulsatile modes. All trials were conducted under 100mm Hg of circuit pressure at normothermia (35°C). In each trial, bolus air (0.5mL) was injected into the circuit at the prepump site over 5s. Total emboli counts and total emboli volume were significantly reduced by the Quadrox-i Neonatal membrane oxygenator compared to the Capiox RX05 membrane oxygenator. Classification and quantification of GME detected at the postoxygenator site at two different flow rates indicated that the Quadrox-i Neonatal captures the majority of microemboli larger than 40µm in diameter. The Quadrox-i Neonatal membrane oxygenator had a higher transmembrane pressure drop at 500mL/min, whereas it had a lower pressure drop at 1000mL/min compared to the Capiox Baby RX05 oxygenator. Additionally, the Quadrox-i Neonatal oxygenator preserved more pulsatile energy than the Baby RX05 oxygenator at both flow rates. Compared to the Capiox RX05 membrane oxygenator, the Quadrox-i Neonatal membrane oxygenator has significantly improved GME handling capacity and had better hemodynamic energy preservation. Further research encompassing in vivo and clinical studies is needed to investigate the magnitude and mechanisms of these benefits.

During extracorporeal life support (ECLS), a large portion of the hemodynamic energy is lost to various components of the circuit. Minimization of this loss in the circuit leads to better vital organ perfusion and decreases the risk of systemic inflammation. In this study, we evaluated the hemodynamic properties of differing lengths of tubing in a simulated neonatal ECLS circuit. The neonatal ECLS circuit used in this study included a Capiox Baby RX05 oxygenator (Terumo Corporation, Tokyo, Japan), a Rotaflow centrifugal pump (MAQUET Cardiopulmonary AG, Hirrlingen, Germany), and a heater and cooler unit. An 8Fr Biomedicus arterial and a 10Fr Biomedicus venous cannula were connected to the pseudopatient. One-fourth inch tubing was used for both the arterial and the venous line. A Hoffman clamp was located upstream from the pseudopatient to maintain a certain patient pressure. Three pressure transducers were placed at different sites: postoxygenator, prearterial cannula, and postarterial cannula. The system was primed with Lactated Ringer's solution; human blood was then added to maintain a hematocrit of 40%. The volume of the pseudopatient was 500mL. We hemodynamically evaluated three circuits with different lengths of tubing: 6, 4, and 2 feet (182.88, 121.92, and 60.96 cm, respectively) for both arterial and venous lines; the priming volumes including all of the components of the circuits were 195, 155, and 115mL, respectively. In each circuit, we measured the pressure drops of the arterial tubing and the arterial cannula, as well as the flow rates at different rpm (1750-3000, 250 intervals) under three patient pressures (40, 60, and 80mm Hg). All the experiments were conducted at 37°C. The pressure drop across the arterial cannula is much larger than that of arterial tubing in all set-ups, especially under high flow rates. Upon cutting the tubing from 6 to 2 feet, the pressure drop of the arterial tubing decreased by half, while the pressure drop of the arterial cannula increased due to the slightly higher flow rates. These results suggest that compared to the arterial tubing, the arterial cannula has a larger impact on the hemodynamics of the circuit. There is a little influence of tubing length on the circuit flow rate.