Thanks for your response. Perfusionists in our center are not so interested in using pulsatile flow. In deed, searching the literature, there is not consensus that pulsatile flow is superior to continuous flow in all patients (see references below). Some researchers recommend it in prolonged operation or critically ill patients. I wonder whether using it in all patients has any disadvantages or not. Please share your experiences and ideas.

Poswal P, et al. Comparative study of pulsatile and nonpulsatile flow during cardio-pulmonary bypass. Ann Card Anaesth 2004; 7: 44–50.

Sink JD, et al. Comparison of nonpulsatile and pulsatile extracorporeal circulation

on renal cortical blood flow. Ann Thorac Surg 1980; 29: 57–62.

Baraki H, et al. Does pulsatile perfusion improve outcome after cardiac surgery? A propensity-matched analysis of 1,959 patients. Perfusion 2012; 27: 166–174.

Presta P, et al. Can pulsatile cardiopulmonary bypass prevent perioperative renal dysfunction during myocardial revascularization in elderly patients? Nephron Clin Pract 2009; 111:c229–c235.

Adademir T, et al. The effects of pulsatile cardiopulmonary bypass on acute

kidney injury. Int J Artif Organs 2012; 35: 511–519.

The question of whether to pulse or not to pulse during CPB is an enduring one. The one consistent finding in studying pulsatile flow during CPB is a beneficial effect on renal function, often manifest at the most fundamental level as increased urine production. However, the impact of pulsatile flow during CPB is most likely to be of greatest significance in patients undergoing prolonged procedures at the extremes of age. The trend towards shorter periods of CPB over the past couple of decades may obviate many of the perceived benefits. However, the oft highlighted aging population, complicated with co-morbidities of renal origin may herald an increase in interest in pulsatile flow. Indeed this factor is once again currently undergoing widespread study. The potential benefits in this cohort of patients may be further increased through the reduction in PVR associated with PCPB, leading to improved peripheral perfusion and some associated reduction in regional ischaemia reperfusion effects. There is considerable evidence supporting PCPB in longer more complex procedures, but the issue remains controversial, possibly due to some moderation of impact when contrasted with other advances in CPB and open heart surgical techniques and technologies. In addition the technical challenge of producing pulsatile flow of physiological proportions using typical CPB pumps in a cluttered perfusion circuit remains a challenge. A review of the literature on this subject can be confusing, but it is a large body of work and worth consulting prior to deployment of PCPB, a least to determine the most suitable P.flow control characteristics and clinical environment (anaesthetic technique etc) to optimise benefit with particular perfusion systems. These a key factors.

Many thanks Terence,

In an attempt to shed further light on this controversial topic, I'd like to know your opinion about possible contraindications for employing pulsatile CPB such as severe aortic calcification and aortic plaques.

I am using pulsatile flow and to my best knowledge there is no publication demonstrating drawback of pulsatile perfusion. 

I agree, that there is no consensus on the efficiency of pulsatile perfusion, but many works published did not demonstrate correctly the quality of pulsatile perfusion.

Pulsatile perfusion depends on several parameters and we know that pumps with FDA approval for pulsatile flow are unable to perform pulsatile flow. Pulsatile flow depends on energy gradient and not on pressure gradient. 

Recent blood roller pumps can generate pulsatile flow, but the quality depends also on the bypass circuit downstream the pump and mainly on the oxygenator and on the arterial cannula.