EFFFCTS OF HYPOTENSIVE ANESTHESIA ON CORONARY ARTERY AND MYOCARDIUM DURING ORAL SURGERY

I.实验研究：心内膜下区是心脏最易受缺血或缺氧损伤的区域。本研究旨在观察和比较硝酸甘油（NTG）、异氟醚（ISO）和三磷酸腺苷（ATP）控制性降压时，活体心肌组织氧分压（PO 2，mmHg）和局部血流量（BF，ml/100 g/min）的变化。在正常心脏中，在药物诱导的分级降压期间，心外膜层灌注和代谢活性相对较好地维持。内分泌层PO_2受影响最大，并伴有BF不同程度的变化，NTG引起的变化最大，ATP引起的变化最小。因此，我们得出结论，虽然NTG被认为是一种良好的心肌血管扩张剂，但在低血压时并不一定如此。在ATP的作用下，心肌BF和PO 2值在所有阶段都保持在对照的80%以上。临床研究：已知ATP、前列腺素E1和硝酸甘油是强效和极短作用的血管扩张剂，可产生短暂但严重的低血压。因此，这些。药剂特别适合于需要快速控制血压的短时间外科手术。当需要长期降压时，可能需要大剂量的血管扩张剂。在这项研究中，我们发现双嘧达莫将ATP剂量减少到1/10至1/15，以达到相同的血压下降。ATP/双嘧达莫对人的心血管（包括冠状动脉）和代谢参数有非常好的影响，在血液和尿液中均未检测到有害或不良的变化。因此，ATP/双嘧达莫组合可以比前列腺素E1或硝酸甘油更安全地用于临床。

I. Experimental study:The subendocardium is known to be the most vulnerable ergion of the heart to ischemic or hypoxic injury. The purpose of this study was to examine and compare the changes of 1) myocardial tissue oxygen tension(PO2, mmHg) and 2) regional blood flow (BF, ml/100g/min) by direct online measurement from the living myocardium during induced hypotension with nitroglycerine (NTG),isoflurane (ISO) or adenosine triphosphate (ATP). In normal heart, during drug induced graded hypotension, epicardial layer perfusion and metabolic activity were relatively well maintained. Endocardial layer PO2 was most affected and disturbed which was accompanied by various degrees of BF changes: NTG causing the most, and ATP the least changes. Thus, we conclude that although NTG is considered a good myocardial vasodilator, this is not necessarily so during hypotension.With ATP, both myocardial BF and PO2 values were maintained well above 80% of control in all stages of hypotension.II. Clinical study:ATP, prostaglandin E1 and nitroglycerine are known to be potent and extremely short acting vasodilators, producing transient but profound hypotension. For this reason, these. agents have been particularly suited for short time surgical procedures which require rapid control of blood pressure. When hypotension is needed for long periods, the large doses of vasodilators may be required.In this study, we found that dipyridamode reduced the ATP dose requirement to 1/10 to 1/15 to attain the same BP reduction. ATP/Dipyridamole showedvery favorable effects on both cardiovascular (includes coronary artery) and metabolic parameters during and after prolonged infusion (>4 hrs) in man. No deleterious or adverse changes were detected in neither blood nor ruine. Thus, the ATP/Dipyridamole combination can be more safely used chinically than prostaglandin E1 or nitroglycerine.