Positive effects of pulsatile flow:
- Improved cerebral oxygen saturation and increased pulsatility index in the middle-cerebral artery
- increased blood flow perfusion in the microcirculation and capillaries
- improved oxygen consumption and extraction ratio due to increased microcirculation
- increased myocardial, pulmonary, renal, cerebral, pancreatic, uteroplacental, and gastrointestinal mucosal blood flow
- reduced endothelial damage
- attenuated systemic inflammatory response and decreased fibrinolytic activation
Negative effects of pulsatile flow:
- Higher levels of hemolysis due to high velocity jetting flow
- decreased gaseous micro-bubble filtering properties of oxygenators
- increased number of GME produced by splitting of the existing bubbles in the circuit (not by additional gas production in the circuit)
Ündar concludes: Each component of the cardiopulmonary bypass must be evaluated in terms of hemodynamic impact prior to clinical use. In addition, precise quantification of pressure and flow waveforms using various pulsatile flow settings are required for meaningful comparisons. Current roller pumps can generate sufficient pulsatility to achieve better clinical outcomes, particularly in high risk patients. In terms of safety during cardiopulmonary bypass, pulsatile flow should only be used during aortic cross-clamping. Additionally, a Transcranial Doppler device should be utilized to not only measure the quality of pulsatility but also to monitor potential emboli delivery in real time.