Evaluation of two pediatric polymethyl pentene membrane oxygenators with pulsatile and non-pulsatile perfusion.

OBJECTIVES: This experiment sought to compare two polymethyl pentene (PMP) hollow-fiber membrane oxygenators: the Medos HILITE 2400 LT and the Maquet Quadrox-iD Pediatric in terms of transmembrane pressure gradients and hemodynamic energy preservation under both pulsatile and non-pulsatile conditions. METHODS: A simulated pediatric extracorporeal life support (ECLS) circuit was used to test these two oxygenators. The circuit consisted of a roller pump, » inch tubing for both arterial and venous lines, an oxygenator, and a venous reservoir served as a pseudo-patient. Three pressure transducers were placed upstream and downstream of the oxygenator and the distal arterial line. The experimental system was primed with lactated Ringer's solution and packed human red blood cells to maintain a hematocrit of 40%.The total volume was 600 ml, including the 350 ml volume of the pseudo-patient.The tests were performed at six flow rates (250, 500, 750, 1000, 1250, 1500 ml/min) and three distal arterial line pressures (MAP) (60, 80, 100 mmHg), under both pulsatile and non-pulsatile perfusion modes.The temperature was kept constant at 37°C for all tests. RESULTS: Both oxygenators had adequate performances in pressure drop and hemodynamic energy preservation. There were no significant differences between pre- and post-oxygenators for mean pressure (MP), energy equivalent pressure (EEP) and total hemodynamic energy (THE). During the pulsatile perfusion mode, the HILITE 2400 LT retained a greater percentage of surplus hemodynamic energy (SHE) across the oxygenator. CONCLUSIONS: Both the Quadrox-iD Pediatric and HILITE 2400LT PMP membrane oxygenators are suitable for pediatric ECLS therapy under both non-pulsatile and pulsatile perfusion. An optimized combination of flow rate and MAP should be achieved in order to deliver the maximal pulsatile energy in the extracorporeal circuit.

Translational research in pediatric extracorporeal life support systems and cardiopulmonary bypass procedures: 2011 update.

Over the past 6 years at Penn State Hershey, we have established the pediatric cardiovascular research center with a multidisciplinary research team with the goal to improve the outcomes for children undergoing cardiac surgery with cardiopulmonary bypass (CPB) and extracorporeal life support (ECLS). Due to the variety of commercially available pediatric CPB and ECLS devices, both in vitro and in vivo translational research have been conducted to achieve the optimal choice for our patients. By now, every component being used in our clinical settings in Penn State Hershey has been selected based on the results of our translational research. The objective of this review is to summarize our translational research in Penn State Hershey Pediatric Cardiovascular Research Center and to share the latest results with all the interested centers.

Pediatric cardiopulmonary bypass: does perfusion mode matter?

This current review describes how components of the cardiopulmonary bypass (CPB) circuit are selected and examines the benefits of pulsatile perfusion for use during CPB. Pulsatile flow generates significantly greater surplus hemodynamic energy (SHE) than nonpulsatile flow; higher SHE values have been associated with better microcirculation perfusion, lower rates of systemic inflammatory response, and better vital organ protection. Pulsatile perfusion may have a positive effect on clinical outcomes, play a role in preserving homeostasis, and help to decrease morbidity associated with CPB.

Comparison of perfusion quality in hollow-fiber membrane oxygenators for neonatal extracorporeal life support.

Perfusion quality is an important issue in extracorporeal life support (ECLS); without adequate perfusion of the brain and other vital organs, multiorgan dysfunction and other deficits can result. The authors tested three different pediatric oxygenators (Medos Hilite 800 LT, Medtronic Minimax Plus, and Capiox Baby RX) to determine which gives the highest quality of perfusion at flow rates of 400, 600, and 800 mL/min using human blood (36 degrees C, 40% hematocrit) under both nonpulsatile and pulsatile flow conditions. Clinically identical equipment and a pseudo-patient were used to mimic operating conditions during neonatal ECLS. Traditionally, the postoxygenator surplus hemodynamic energy value (SHE(post), extra energy obtained through pulsatile flow) is the one relied upon to give a qualitative determination of the amount of perfusion in the patient; the authors also examined SHE retention through the membrane, as well as the contribution of SHE(post) to the postoxygenator total hemodynamic energy (THE(post)). At each experimental condition, pulsatile flow outperformed nonpulsatile flow for all factors contributing to perfusion quality: the SHE(post) values for pulsatile flow were 4.6-7.6 times greater than for nonpulsatile flow, while the THE(post) remained nearly constant for pulsatile versus nonpulsatile flow. For both pulsatile and nonpulsatile flow, the Capiox Baby RX oxygenator was found to deliver the highest quality of perfusion, while the Minimax Plus oxygenator delivered the least perfusion. It is the authors' recommendation that the Baby RX oxygenator running under pulsatile flow conditions be used for pediatric ECLS, but further studies need to be done in order to establish its effectiveness beyond the FDA-approved time span.

The multiplier method for prediction of adult height.

The authors propose the "height multiplier method," a new, simple, universal method to predict adult height. The authors calculated age- and gender-specific height multiplier values and validated their use for height prediction. Average height multiplier values (M) for boys and girls were calculated by dividing height at skeletal maturity (Htm) by present height (Ht) for each age, gender, and height percentile (M=Htm/Ht) using data published by the Centers for Disease Control and Prevention (CDC). The accuracy of the multiplier method was compared with the CDC growth charts using longitudinal growth data from 52 normal children. No significant differences were noted between predictions made using the CDC growth charts versus the multiplier method. The authors also compared the CDC-derived multiplier values with other growth databases from around the world and from different eras. Height multipliers were independent of height percentile, race, and generation, indicating that the multiplier method is universal.