Cardiopulmonary bypass with physiological flow and pressure curves: pulse is unnecessary!☆

Abstract

Even when using pulsatile flow patterns which mimic closely the physiological waveforms, there is no advantage concerning organ perfusion or inflammatory response. Moreover, the extent of haemolysis and capillary leak is higher compared to non-pulsatile perfusion. Efforts to optimise pulsatility are not justified.

A review of postoperative cognitive dysfunction and neuroinflammation associated with cardiac surgery and anaesthesia

“…However, a study using single photon positron-emission computed tomography failed to show significant correlations between changes in regional and global cerebral blood flow, and POCD [38]. The hypothesis that a pulsatile flow pattern in the CPB circuit would improve outcomes has also been opposed by several studies that found no beneficial effect of pulsatile flow compared with constant pump flow on organ perfusion [39], the inflammatory response, endothelial activation [40], and microcirculatory blood flow as seen with sublingual microvascular video recordings [41], brain tissue oxygenation [42], or cognitive outcomes two months after surgery [43]. Likewise, two cohort studies have failed to show an effect of temperature management during CPB on postoperative cerebral oedema [27,28] and a large blinded randomised controlled trial (class-2b evidence) showed no effect on cognitive function [44].…”

“Flow and Rate”: Concept and Clinical Applications of a New Hemodynamic Theory

“…Meanwhile, the benefits of normothermia on myocardial protection and microcirculation improvements remain controversial (Rastan, et al, 2008), as the myocardium is already protected with doses of cardioplegia, while the perfusion of microcirculation is more or less helped by the FahraeusLindqvist effect due to hemodilution; c) total or partial absenteeism of CPB: that becomes popular with proven postoperative hemodynamic advantages, but it is still a challenging technique reserved for selected groups of patients (Shroyer, et al, 2009); d) pulsatile perfusion flow devices: in a matter to keep ESS some pulsatile CPB have proven advantages clinically and experimentally (Ündar, et al,1999); (Undar, et al 2006). Despite that, recent studies recommend the unphysiological steady flow (Voss, et al, 2010). This may be explained by pulsatile CPB inadequate curves with the necessity of a double perfusion pumps system to compensate the oxygenators momentum energy losses.…”

Intraaortic Counterpulsation During Cardiopulmonary Bypass Impairs Distal Organ Perfusion

“…Consequently, assessment of perfusion pressure distal to the balloon should be addressed whenever IABP is used during CPB. T he controversy of pulsatile vs nonpulsatile perfusion during cardiopulmonary bypass (CPB) remains unsolved [1,2]. Although a number of studies are unable to demonstrate any advantage of pulsed CPB perfusion [2][3][4], pulsatile CPB flow has been associated with improved cardiac, renal, and pulmonary outcomes, better cytokine profiles, endothelin and hormone levels, and an improved respiratory index [1].…”