| 摘要 |
A peristaltic pump employs a tensioner to add additional stretch to a distensible, compliant segment of tubing stretched around pin rollers mounted (120) degrees apart on a rotating wheel just before stretch is released on the segment as the wheel rotates. The release creates a pressure wave giving a pulsatile flow. The tubing is not compressed against a raceway, but is tensioned against rollers restricting the lumen of the tubing where it is stretched across the rollers. This feature allows the stretched tubing to function as a capacitance reservoir, eliminating the need for upstream and downstream reservoirs. The volume of blood in the header tubing varies according to available venous return. When outflow obstruction occurs, blood accumulates in the header tubing. As the tubing distends, it becomes progressively less occlusive, so that over pressure is avoided. When the obstruction is released, blood flows downstream rapidly propelled by the large stroke volume of the distended header tubing. The tubing is never totally occlusive, so that negative pressure, blood cell lysis and degassing do not occur. |
