Quantification of Perfusion Modes in Terms of Surplus Hemodynamic Energy Levels in a Simulated Pediatric CPB Model

The objective of this investigation was to compare pulsatile versus nonpulsatile perfusion modes in terms of surplus hemodynamic energy (SHE) levels during cardiopulmonary bypass (CPB) in a simulated neonatal model. The extracorporeal circuit consisted of a Jostra HL-20 heart-lung machine (for both pulsatile and nonpulsatile modes of perfusion), a Capiox Baby RX hollow-fiber membrane oxygenator, a Capiox pediatric arterial filter, 5 feet of arterial tubing and 6 feet of venous tubing with a quarter-inch diameter. The circuit was primed with a lactated Ringers solution. The systemic resistance of a pseudo-patient (mean weight, 3 kg) was simulated by placing a clamp at the end of the arterial line. The pseudo-patient was subjected to five pump flow rates in the 400 to 800 ml/min range. During pulsatile perfusion, the pump rate was kept constant at 120 bpm. Pressure waveforms were recorded at the preoxygenator, postoxygenator, and preaortic cannula sites. SHE was calculated by use of the following formula {SHE (ergs/cm3) = 1,332 [((∫ fpdt) / (∫ fdt)) – Mean Arterial Pressure]} (f = pump flow and p = pressure). A total of 60 experiments were performed (n = 6 for nonpulsatile and n = 6 for pulsatile) at each of the five flow rates. A linear mixed-effects model, which accounts for the correlation among repeated measurements, was fit to the data to assess differences in SHE between flows, pumps, and sites. The Tukey multiple comparison procedure was used to adjust p values for post hoc pairwise comparisons. With a pump flow rate of 400 ml/min, pulsatile flow generated significantly higher surplus hemodynamic energy levels at the preoxygenator site (23,421 ± 2,068 ergs/cm3 vs. 4,154 ± 331 ergs/cm3, p < 0.0001), the postoxygenator site (18,784 ± 1,557 ergs/cm3 vs. 3,383 ± 317 ergs/cm3, p < 0.0001), and the precannula site (6,324 ± 772 ergs/cm3 vs. 1,320 ± 91 ergs/cm3, p < 0.0001), compared with the nonpulsatile group. Pulsatile flow produced higher SHE levels at all other pump flow rates. The Jostra HL-20 roller pump generated significantly higher SHE levels in the pulsatile mode when compared with the nonpulsatile mode at all five pump flow rates.

[1]  A. Ündar.  Pulsatile Versus Nonpulsatile Cardiopulmonary Bypass Procedures in Neonates and Infants: From Bench to Clinical Practice , 2005 .

[2]  A. Şaşmazel,et al.  Postoperative Prophylactic Peritoneal Dialysis in Neonates and Infants After Complex Congenital Cardiac Surgery , 2006, ASAIO journal.

[3]  A. Undar,et al.  Comparison of hollow-fiber membrane oxygenators in terms of pressure drop of the membranes during normothermic and hypothermic cardiopulmonary bypass in neonates. , 2003, Perfusion.

[4]  A. Ündar,et al.  AN IN VIVO COMPARISON OF INFANT MEMBRANE OXYGENATORS FOR PULSATILE CARDIOPULMONARY BYPASS , 1996 .

[5]  G Wright,et al.  Hemodynamic analysis could resolve the pulsatile blood flow controversy. , 1994, The Annals of thoracic surgery.

[6]  A. Ündar,et al.  Pulsatile ECMO in Neonates and Infants: First European Clinical Experience with a New Device , 2005, ASAIO journal.

[7]  C. Fraser,et al.  Pulsatile Perfusion Improves Regional Myocardial Blood Flow during and after Hypothermic Cardiopulmonary Bypass in a Neonatal Piglet Model , 2000, ASAIO journal.

[8]  A Undar,et al.  Pulsatile and nonpulsatile flows can be quantified in terms of energy equivalent pressure during cardiopulmonary bypass for direct comparisons. , 1999, ASAIO journal.

[9]  C. Fraser,et al.  Comparison of hollow-fiber membrane oxygenators in terms of pressure drop of the membranes during normothermic and hypothermic cardiopulmonary bypass in neonates , 2005 .

[10]  A Undar,et al.  Effects of perfusion mode on regional and global organ blood flow in a neonatal piglet model. , 1999, The Annals of thoracic surgery.

[11]  A. Undar,et al.  Precise Quantification of Pulsatility is a Necessity for Direct Comparisons of Six Different Pediatric Heart-Lung Machines in a Neonatal CPB Model , 2005, ASAIO journal.

[12]  R B Shepard,et al.  Energy equivalent pressure. , 1966, Archives of surgery.

[13]  A. Ündar,et al.  Effects of Pulsatile and Nonpulsatile Perfusion on Vital Organ Recovery in Pediatric Heart Surgery: A Pilot Clinical Study , 2006, ASAIO journal.

[14]  Akif Undar,et al.  An Evaluation of the Benefits of Pulsatile versus Nonpulsatile Perfusion during Cardiopulmonary Bypass Procedures in Pediatric and Adult Cardiac Patients , 2006, ASAIO journal.

[15]  Akif Ündar,et al.  Myths and truths of pulsatile and nonpulsatile perfusion during acute and chronic cardiac support. , 2004 .

[16]  Scott B. Johnson,et al.  Testing neonate-infant membrane oxygenators with the University of Texas neonatal pulsatile cardiopulmonary bypass system in vitro , 1998, Perfusion.

[17]  Gerson Rosenberg,et al.  Major factors in the controversy of pulsatile versus nonpulsatile flow during acute and chronic cardiac support. , 2005, ASAIO journal.