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Pulsatile blood flow enhances kidney function, lymph flow, and oxygen consumption compared to nonpulsatile flow during cardiopulmonary bypass (CPB). This improved perfusion may be due to vascular shocks, increased lymph movement, and better vascular patency.
Area of Science:
- Cardiovascular physiology
- Biomedical engineering
Background:
- Pulsatile and nonpulsatile blood flow are critical in cardiopulmonary bypass (CPB), organ perfusion, and myocardial preservation.
- While early research was divided, recent studies indicate advantages of pulsatile flow.
Purpose of the Study:
- To review the benefits of pulsatile flow over nonpulsatile flow in various medical applications.
- To explore the physiological mechanisms underlying the superiority of pulsatile perfusion.
- To discuss novel methods for generating pulsatile flow.
Main Methods:
- Literature review comparing pulsatile and nonpulsatile blood flow studies.
- Analysis of physiological parameters affected by different flow types.
- Discussion of theoretical explanations for pulsatile flow's efficacy.
Main Results:
- Pulsatile perfusion improves kidney function, lymph flow, and oxygen consumption.
- Nonpulsatile CPB can lead to increased total peripheral resistance and mean arterial pressure.
- Proposed mechanisms include "vascular shocks," enhanced interstitial fluid diffusion, increased lymph movement, and maintained vascular patency.
Conclusions:
- Pulsatile blood flow offers significant physiological benefits over nonpulsatile flow.
- Understanding these benefits is crucial for optimizing CPB and organ perfusion strategies.
- Advancements in generating pulsatile flow are being adapted for clinical use.
Abstract:
Pulsatile and nonpulsatile blood flow have been intensely studied for cardiopulmonary bypass (CPB), isolated organ perfusion, and myocardial preservation. Although early studies differed, later ones have shown the benefits of pulsatile flow. Kidney function, lymph flow, and oxygen consumption are increased during pulsatile perfusion. Also, nonpulsatile CPB increases total peripheral resistance and mean arterial pressure, which are related to time of perfusion. Theories to account for the superiority of pulsatile flow include: (1) "vascular shocks" causing physical displacement of tissues, which changes the boundary layer of interstitial fluid around cell membranes and enhances diffusion ;(2) increased lymph movement during pulsatile flow; and (3) pulsatile energy ensuring the patency of the vascular beds and preventing shunting. New methods to create pulsatile flow and their adaptation to the standard roller pump are discussed.