Department of Anaesthesia and Intensive Care, Treviso Regional Hospital, Treviso, Italy.
J Cardiothorac Vasc Anesth. 2012 Oct;26(5):785-90. doi: 10.1053/j.jvca.2012.01.017. Epub 2012 Mar 2.
The flow rate of the cardiopulmonary bypass (CPB) pump used in cardiac surgery often undergoes inherent fluctuations ranging from 10% to 20% of its theoretic value. However, the effects of such alterations remain unknown. In the present study, the authors investigated whether such variations could induce changes in the microvascular flow, which is considered a primary indicator of poor perfusion.
A prospective, observational, clinical study.
A university-affiliated teaching hospital.
Thirty adult patients undergoing elective cardiac surgery with CPB.
Analysis of the sublingual microcirculation during CPB using a pump flow rate of 80% or 100% of the theoretic value.
Sidestream dark field (SDF) imaging was used to record 2 video clips of the sublingual microcirculation in each patient. The videos were recorded at the same site at 80% and 100% of the theoretic flow rate. Microvascular analysis displaying the De Backer score, the microvascular flow index, the total vessel density, the perfused vessel density, and the proportion of perfused vessels was performed. Moreover, the mean arterial pressure (MAP), SvO(2), and PaCO(2) were evaluated. No significant changes in the measured parameters were noted at the 2 different flow rates.
Changes in the CPB pump flow rate within 20% (80%-100%) of its theoretic value do not alter the sublingual microcirculation. Thereafter, it is conceivable that during perioperative adjustments of the CPB pump rate, blood flow autoregulation mechanisms are activated so that limited changes in the pump flow can be considered safe not only at the sublingual site but also for the entire microcirculation.
心脏手术中体外循环（CPB）泵的流量通常会经历从其理论值的 10%到 20%的固有波动。然而，这些变化的影响尚不清楚。在本研究中，作者研究了这些变化是否会引起微血管流量的变化，而微血管流量被认为是灌注不良的主要指标。
前瞻性、观察性、临床研究。
一所大学附属医院。
30 名接受 CPB 择期心脏手术的成年患者。
使用 80%或 100%理论流量的 CPB 泵流量分析舌下微循环。
使用边流暗场（SDF）成像记录每位患者舌下微循环的 2 个视频片段。在 80%和 100%理论流量的相同部位记录视频。进行微血管分析，显示德贝克评分、微血管血流指数、总血管密度、灌注血管密度和灌注血管比例。此外，评估平均动脉压（MAP）、SvO2 和 PaCO2。在 2 个不同流速下，测量参数没有明显变化。
CPB 泵流量在其理论值的 20%（80%-100%）范围内的变化不会改变舌下微循环。此后，可以想象，在 CPB 泵率的围手术期调整过程中，血液流动自动调节机制被激活，因此泵流量的有限变化不仅在舌下部位，而且在整个微循环中被认为是安全的。
