Ihara T, Shannon R P, Komamura K, Pasipoularides A, Patrick T, Shen Y T, Vatner S F
Department of Medicine, Harvard Medical School, Beth Israel Hospital, Boston, MA.
Cardiovasc Res. 1994 Mar;28(3):325-36. doi: 10.1093/cvr/28.3.325.
The aims were to determine the effects and the extent to which halothane anaesthesia affects diastolic function both immediately after and remote from surgery and to investigate whether the effect is due to alterations in loading conditions.
Eight mongrel dogs were studied under halothane anaesthesia (0.5-1.5 end tidal vol%) with the chest closed, after acute instrumentation with left ventricular pressure transducers, left atrial and aortic catheters, and left ventricular diameter and wall thickness crystals. The same dogs were then studied in the fully conscious state, 2-3 weeks later. An additional four dogs were studied in the conscious state and then again under halothane anaesthesia remote from acute instrumentation. The left ventricular isovolumetric relaxation time constant, tau, as well as myocardial and chamber stiffness constants were used as indices of diastolic function.
Following halothane anaesthesia and recent surgery, tau was prolonged significantly compared to the conscious state, at 30(SEM 1) v 22(1) ms (p < 0.01), but there were no changes in either myocardial or chamber stiffness. While tau remained sensitive to increased heart rate and enhanced contractility and was prolonged by increasing afterload in both the anaesthetised and conscious states, it was consistently prolonged following halothane anaesthesia and recent surgery even at matched levels of contractile states, heart rates and loading conditions, compared to the conscious state, at 26(1) v 19(1) ms (p < 0.01). When the effects of halothane anaesthesia were examined after full recovery from surgery, tau was still prolonged under halothane anaesthesia, at 29(2) v 20(1) ms (p < 0.01), compared to the conscious state, but in contrast to the findings following halothane anaesthesia and recent surgery, it was fully normalised [19(1) v 19(1) ms] when contractile state and loading conditions were matched.
Left ventricular diastolic function is influenced markedly by halothane anaesthesia and recent surgery, and to a degree comparable to many pathological states. The effects of halothane anaesthesia and recent surgery appear to prolong the isovolumetric relaxation time constant independently of heart rate, contractility, and loading conditions and are most likely to be due to the combined direct effects of anaesthetics and acute instrumentation.
本研究旨在确定氟烷麻醉对手术刚结束时及术后远期舒张功能的影响及程度，并探究该影响是否由负荷条件改变所致。
选用8只杂种犬，在氟烷麻醉（呼气末浓度0.5 - 1.5%）下，于胸部闭合状态下进行急性仪器植入，植入左心室压力传感器、左心房及主动脉导管以及左心室直径和壁厚晶体。2 - 3周后，在完全清醒状态下对同一只犬再次进行研究。另外4只犬先在清醒状态下进行研究，然后在远离急性仪器植入的情况下再次接受氟烷麻醉。左心室等容舒张时间常数（tau）以及心肌和心室僵硬度常数用作舒张功能指标。
与清醒状态相比，氟烷麻醉及近期手术后，tau显著延长，分别为30（标准误1）毫秒和22（1）毫秒（p < 0.01），但心肌或心室僵硬度均无变化。尽管tau在麻醉和清醒状态下均对心率增加、收缩力增强敏感，且后负荷增加会使其延长，但与清醒状态相比，即使在收缩状态、心率和负荷条件匹配的情况下，氟烷麻醉及近期手术后tau仍持续延长，分别为26（1）毫秒和19（1）毫秒（p < 0.01）。当在手术后完全恢复后检查氟烷麻醉的影响时，与清醒状态相比，氟烷麻醉下tau仍延长，分别为29（2）毫秒和20（1）毫秒（p < 0.01），但与氟烷麻醉及近期手术后的结果不同，当收缩状态和负荷条件匹配时，tau完全恢复正常[19（1）毫秒和19（1）毫秒]。
氟烷麻醉和近期手术对左心室舒张功能有显著影响，其程度与许多病理状态相当。氟烷麻醉和近期手术的影响似乎独立于心率、收缩力和负荷条件延长等容舒张时间常数，最可能是由于麻醉剂和急性仪器植入的联合直接作用。
