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We thank Drs Ji and Luo [1Ji B. Luo Y. Importance of precise quantification of pressure-flow waveforms in comparison between pulsatile versus non-pulsatile perfusion.Ann Thorac Surg. 2009; 87 (letter): 988Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar] for their interest in our work [2Siepe M. Goebel U. Mecklenburg A. et al.Pulsatile pulmonary perfusion during cardiopulmonary bypass reduces the pulmonary inflammatory response.Ann Thorac Surg. 2008; 86: 115-122Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar] and their important input. We would like to briefly comment on the issues they have raised. From years of research on pulmonary perfusion in animal projects and in clinical trials, we have identified 20% of the systemic flow as being the optimal and most practical volume of pulmonary perfusion. It represents a volume that can be drawn off the reservoir without altering systemic perfusion. Thereby, physiologic pulmonary arterial pressures can be maintained with or without pulsatility. Using this strategy, we achieved the main objective of pulmonary perfusion, namely, the prevention of pulmonary ischemic and inflammatory injury during cardiopulmonary bypass [2Siepe M. Goebel U. Mecklenburg A. et al.Pulsatile pulmonary perfusion during cardiopulmonary bypass reduces the pulmonary inflammatory response.Ann Thorac Surg. 2008; 86: 115-122Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar, 3Schlensak C. Doenst T. Preusser S. Wunderlich M. Kleinschmidt M. Beyersdorf F. Cardiopulmonary bypass reduction of bronchial blood flow: a potential mechanism for lung injury in a neonatal pig model.J Thorac Cardiovasc Surg. 2002; 123: 1199-1205Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar]. We admit that the shape and quantification of the pulsatile waveform are important factors. The quantification methods mentioned by Ji and Luo are entirely convincing, and we will take the formulas they propose into account in our future investigations. In this study, we adjusted the pulsatile pulmonary perfusion to make it easy to reproduce and translate into clinical routine. In detail, we introduced a 14F pediatric polyurethane cannula (Stöckert Instruments GmbH, Munich, Germany) in the proximal main pulmonary artery. Pulsatile perfusion was achieved using a diagonal pump (DELTASTREAM DP1, MEDOS Medizinitechnik AG, Stolberg, Germany). We connected the pump to a soft venous bag for neonates (D 901, Sorin S.p.A., Milan, Italy). Using these tools, the perfusionist was able to create a well-shaped pressure curve in all experiments. The curve resembled the normal pulsatile profile in the pulmonary artery. We find that this strategy for ensuring pulsatile pulmonary perfusion throughout the experiments is easy to perform and that it has convincing advantages for the lungs during cardiopulmonary bypass. Importance of Precise Quantification of Pressure-Flow Waveforms in Comparison Between Pulsatile Versus Nonpulsatile PerfusionThe Annals of Thoracic SurgeryVol. 87Issue 3PreviewWe read with great interest the article by Siepe and colleagues [1]. In this particular animal research, to avoid ischemia of the lungs during cardiopulmonary bypass (CPB), the authors used active pulmonary perfusion and compared the effects of two different perfusion modes (pulsatile vs nonpulsatile perfusion) on pulmonary inflammatory response and apoptosis in the lungs. They concluded that active pulsatile pulmonary perfusion reduces the inflammatory response and apoptosis in the lungs during CPB. Full-Text PDF