Pulsatile and Nonpulsatile Flows Can Be Quantified in Terms of Energy Equivalent Pressure During Cardiopulmonary Bypass for Direct Comparisons

Ündar, Akif; Masai, Takafumi; Frazier, O. H.; Fraser, Charles D.

doi:10.1097/00002480-199911000-00017

Cited by 74 publications

(71 citation statements)

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“…[33][34][35][36][37][38][39][40] Pulsatile and nonpulsatile pressure-flow waveforms should be quantified in terms of hemodynamic energy levels because generation of pulsatile flow depends upon an energy gradient. [33][34][35][36][37][38][39][40] We have clearly documented that, with identical pulse pressures, the difference in terms of extra energy between two different pulsatile pumps can be more than 100%. 37 The cause of this difference is the energy contained in each pulsatile cycle.…”

Section: Limitations Of Experimental Designsmentioning

confidence: 99%

Major Factors in the Controversy of Pulsatile Versus Nonpulsatile Flow During Acute and Chronic Cardiac Support

Ündar¹,

Rosenberg²,

Myers³

2005

ASAIO Journal

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During the past 50 years, the controversy over the benefits of pulsatile versus nonpulsatile flow in cardiac surgery has not been solved. 1 A detailed investigation in all published literature reveals that in a majority of publications, the investigators could not show any differences between perfusion modes during acute or chronic cardiac support. However, in more than 20 articles, it appears clear that pulsatile flow causes significantly less vital organ injury and systemic inflammation during cardiopulmonary bypass (CPB) procedures and chronic cardiac circulatory support. 1-23 To the best of our knowledge, there is not a single publication that clearly shows the benefits of nonpulsatile perfusion over pulsatile perfusion in acute or chronic clinical or animal settings. The pro-nonpulsatile flow investigators can only claim that there is no difference between perfusion modes, whereas the pro-pulsatile investigators have documented clear benefits. The objective of this editorial is to examine the major causes for this continuing controversy and suggest potential solutions to end it. Following are the two major causes for the controversy, and both are valid for acute or chronic settings.

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Section: Limitations Of Experimental Designsmentioning

confidence: 99%

Major Factors in the Controversy of Pulsatile Versus Nonpulsatile Flow During Acute and Chronic Cardiac Support

Ündar¹,

Rosenberg²,

Myers³

2005

ASAIO Journal

Self Cite

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show abstract

“…Flow pulsatility has been shown to be beneficial for organ perfusion [27] as well as healthy vascular gene expression and remodelling; however, the energetic cost of delivering a constant CO is higher in pulsatile flow than in non-pulsatile flow [26,72]. In the healthy circulatory system, the pulsatile component of ventricular load operates optimally and constitutes a small fraction of the total power requirement of the ventricle (approx.…”

Section: Non-dimensional Numbers In the Clinical Settingmentioning

confidence: 99%

Non-dimensional physics of pulsatile cardiovascular networks and energy efficiency

Yigit

Pekkan

2016

J. R. Soc. Interface.

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In Nature, there exist a variety of cardiovascular circulation networks in which the energetic ventricular load has both steady and pulsatile components. Steady load is related to the mean cardiac output (CO) and the haemodynamic resistance of the peripheral vascular system. On the other hand, the pulsatile load is determined by the simultaneous pressure and flow waveforms at the ventricular outlet, which in turn are governed through arterial wave dynamics (transmission) and pulse decay characteristics (windkessel effect). Both the steady and pulsatile contributions of the haemodynamic power load are critical for characterizing/comparing disease states and for predicting the performance of cardiovascular devices. However, haemodynamic performance parameters vary significantly from subject to subject because of body size, heart rate and subject-specific CO. Therefore, a 'normalized' energy dissipation index, as a function of the 'non-dimensional' physical parameters that govern the circulation networks, is needed for comparative/ integrative biological studies and clinical decision-making. In this paper, a complete network-independent non-dimensional formulation that incorporates pulsatile flow regimes is developed. Mechanical design variables of cardiovascular flow systems are identified and the Buckingham Pi theorem is formally applied to obtain the corresponding non-dimensional scaling parameter sets. Two scaling approaches are considered to address both the lumped parameter networks and the distributed circulation components. The validity of these non-dimensional number sets is tested extensively through the existing empirical allometric scaling laws of circulation systems. Additional validation studies are performed using a parametric numerical arterial model that represents the transmission and windkessel characteristics, which are adjusted to represent different body sizes and non-dimensional haemodynamic states. Simulations demonstrate that the proposed nondimensional indices are independent of body size for healthy conditions, but are sensitive to deviations caused by off-design disease states that alter the energetic load. Sensitivity simulations are used to identify the relationship between pulsatile power loss and non-dimensional characteristics, and optimal operational states are computed.

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“…12, 13 They also suggested that the high norepinephrine level in the non-pulsatile circulation would affect oxygen metabolism and worsen systemic oxygen uptake in the acute phase. 14, 15 From the standpoint of hemodynamic change, Undar et al showed that pulsatile flow generated higher energy, which may be beneficial for vital organ perfusion, 16 depending on the timing of mechanical beating. 17, 18 Pulsatile flow may be beneficial for end-organ microcirculation 19 and CoF, 20 but it does not change liver circulation.…”

Section: Umeki a Et Almentioning

confidence: 99%

Change of Coronary Flow by Continuous-Flow Left Ventricular Assist Device With Cardiac Beat Synchronizing System (Native Heart Load Control System) in Acute Ischemic Heart Failure Model

Umeki

Nishimura

Ando

et al. 2013

Circ J

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Pulsatile and Nonpulsatile Flows Can Be Quantified in Terms of Energy Equivalent Pressure During Cardiopulmonary Bypass for Direct Comparisons

Cited by 74 publications

References 0 publications

Major Factors in the Controversy of Pulsatile Versus Nonpulsatile Flow During Acute and Chronic Cardiac Support

Major Factors in the Controversy of Pulsatile Versus Nonpulsatile Flow During Acute and Chronic Cardiac Support

Non-dimensional physics of pulsatile cardiovascular networks and energy efficiency

Change of Coronary Flow by Continuous-Flow Left Ventricular Assist Device With Cardiac Beat Synchronizing System (Native Heart Load Control System) in Acute Ischemic Heart Failure Model

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