Butchart E G, Austen W G, McEnany M T
J Thorac Cardiovasc Surg. 1981 Jul;82(1):38-44.
Water equilibrium within heart muscle during cardiopulmonary bypass is an important aspect of ventricular physiology which must be considered in efforts to optimize myocardial protection. This study focuses on the influence of the inotropic state of the ventricle in determining the amount of heart water and its regional distribution within the free wall of the left ventricle. Experiments involving cardiopulmonary bypass were performed in 57 dogs. Three spontaneous levels of myocardial contractility were identified under conditions of standard preload, afterload, and heart rate. Each increase in level (grade) was associated with a significantly higher myocardial wet weight/drug weight (W/D) ratio. In addition, higher levels of contractility were associated with a marked shift in water distribution within the left ventricular wall; water tended to accumulate in the inner half of the better contracting left ventricular wall, the reverse of the distribution seen at lower levels of contractility. These three grades of contractility and myocardial water content were not associated with any significant differences in total or regional myocardial blood flow, as determined by the use off radioactive microspheres. Maintenance of low levels of contractility during cardiopulmonary bypass may be desirable in order to prevent the occurrence of subendocardial edema.
体外循环期间心肌内的水平衡是心室生理学的一个重要方面，在优化心肌保护的努力中必须予以考虑。本研究聚焦于心室变力状态对左心室游离壁内心脏含水量及其区域分布的影响。对57只狗进行了涉及体外循环的实验。在标准前负荷、后负荷和心率条件下，确定了三种自发的心肌收缩力水平。每升高一个水平（等级），心肌湿重/干重（W/D）比值就显著升高。此外，较高的收缩力水平与左心室壁内水分分布的明显变化有关；水分倾向于积聚在收缩较好的左心室壁的内半部，这与较低收缩力水平时的分布情况相反。通过使用放射性微球测定，这三种收缩力等级和心肌含水量与总心肌血流量或区域心肌血流量的任何显著差异均无关联。为防止心内膜下水肿的发生，体外循环期间维持低水平的收缩力可能是可取的。
