Comparison of end-systolic pressure-length relations and preload recruitable stroke work as indices of myocardial contractility in the conscious and anesthetized, chronically instrumented dog.
Comparison of end-systolic pressure-length relations and preload recruitable stroke work as indices of myocardial contractility in the conscious and anesthetized, chronically instrumented dog.
复制标题
比较收缩末压-时长关系和预负荷可复张卒中做功作为清醒和麻醉、长期使用仪器的狗的心肌收缩力指标。
DOI：
10.1097/00000542-199008000-00016
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发表时间：
1990
期刊：
影响因子：
8.8
通讯作者：
Warltier,DC
中科院分区：
文献类型：
--
作者：
Pagel,PS;Kampine,JP;Schmeling,WT;Warltier,DC
开发一种既与负荷无关又易于在体内定量的心肌收缩性指数一直是一项艰巨的任务。最近，三个收缩状态的措施已被提倡，似乎满足这些要求：收缩末期压力-长度关系（ESPLR），ESPLR面积，和区域预负荷可复搏功（PRSW）。由于氟烷和异氟烷对这些收缩性指数的影响尚未研究，因此本研究的目的是比较这些挥发性麻醉剂对收缩功能的影响，通过这些技术在长期仪器犬中进行评价。由于自主神经系统张力在体内显著影响全身血流动力学，因此在存在自主神经系统的药理学阻断的情况下进行实验。四组包括用九只狗进行的36个实验。吸入诱导后，犬维持1.5 MAC和2 MAC氟烷或异氟烷。压力-长度环在通过部分下腔静脉闭塞减少前负荷或通过苯肾上腺素输注增加后负荷平衡1小时后产生。然后分别计算PRSW和ESPLR。从ESPLR中获得的斜率和长度截距变量未能随麻醉深度水平的增加而显著改变，尽管其他收缩性指数显著降低。然而，斜率和长度截距参数组合到ESPLR面积模型中被证明是一种灵敏且易于计算的心肌功能抑制指标。同样，区域PRSW斜率精确地反映了当氟烷（对照组为62+/-10到30+/-6 erg. cm-2.10（-3）。mm-1，2 MAC）或异氟烷（对照组83+/-14至55+/-8 erg. cm-2.10（-3）。mm-1（2MAC）。当比较氟烷和异氟烷的等麻醉浓度时，PRSW斜率也证明了收缩力抑制的显着差异（在1.5 MAC下，氟烷对照为63+/-7%，异氟烷对照为86+/-4%;在2 MAC下，氟烷对照为50+/-5%，异氟烷对照为70+/-6%）。ESPLR面积也准确地证明了最近的体外研究表明，当在体内比较等麻醉剂量的氟烷和异氟烷时，收缩功能的差异性抑制。因此，虽然ESPLR斜率和长度截距变量不能作为心肌收缩力的指标，但ESPLR面积和区域PRSW斜率被证明是清醒和麻醉犬收缩状态的有用指标。
Development of an index of myocardial contractility that is both load independent and easily quantified in vivo has been a difficult task. Recently, three measures of contractile state have been advocated that appear to fulfill these requirements: the end-systolic pressure-length relationship (ESPLR), the ESPLR area, and regional preload recruitable stroke work (PRSW). Because the effects of halothane and isoflurane on these indices of contractility have yet to be studied, the purpose of this investigation was to compare the effects of these volatile anesthetics on contractile function as evaluated via these techniques in chronically instrumented dogs. Because autonomic nervous system tone substantially influences systemic hemodynamics in vivo, experiments were performed in the presence of pharmacologic blockade of the autonomic nervous system. Four groups comprised the 36 experiments that were performed with nine dogs. Following inhalational induction, the dogs were maintained on 1.5 MAC and 2 MAC of halothane or isoflurane. Pressure-length loops were generated after 1 h of equilibration using preload reduction via partial inferior vena caval occlusion or afterload augmentation by a phenylephrine infusion. The PRSW and ESPLR were then calculated, respectively. Slope and length intercept variables obtained from the ESPLR failed to significantly change from control with increasing levels of anesthetic depth despite substantial decreases in other indices of contractility. However, combination of slope and length intercept parameters into the ESPLR area model proved to be a sensitive and easily calculable measure of depressed myocardial function. Similarly, regional PRSW slope precisely reflected changes in contractile state when halothane (62+/-10 for control to 30+/-6 erg. cm-2.10 (-3). mm-1 at 2 MAC) or isoflurane (83+/-14 for control to 55+/-8 erg. cm-2.10 (-3). mm-1 at 2 MAC) were administered. The PRSW slope also demonstrated a significant difference in depressed contractility when equianesthetic concentrations of halothane and isoflurane were compared (63+/-7% of control with halothane versus 86+/-4% of control with isoflurane at 1.5 MAC; 50+/-5% of control with halothane versus 70+/-6% of control with isoflurane at 2 MAC). The ESPLR area also accurately demonstrated the differential depression in contractile function suggested by recent in vitro studies when equianesthetic doses of halothane and isoflurane were compared in vivo. Therefore, while ESPLR slope and length intercept variables fail as indices of myocardial contractility, ESPLR area and regional PRSW slope were shown to be useful indicators of contractile state in the conscious and anesthetized dog.