Cardiopulmonary Reflex Responses during Nitric Oxide inhalation

吸入机械刺激呼吸道可引起多种心肺反应，包括血压、心率的改变以及支气管收缩等。由于人体呼吸道中存在多种受体，如刺激性受体、伸展受体和J受体，吸入一氧化氮等气体可引起心血管病变。近年来，临床上出现了吸入一氧化氮或急性呼吸窘迫综合征患者吸入一氧化氮的现象。然而，目前还没有关于这几点的研究。在本研究中，我们旨在研究吸入气体和呼吸道麻醉对反射反应的影响，结果如下：1)在麻醉犬，5ppm和50ppm的一氧化氮(NO)对动脉压力感受性无明显影响，但显著抑制低氧引起的肺动脉反应。2)吸烟(尼古丁0.1 mg和1 mg，焦油13 mg)引起麻醉大鼠软脑膜小动脉和小静脉收缩。这种效应似乎是一种浓度依赖的方式，可能至少部分是通过尼古丁受体和吸烟激活交感神经。3)使用利多卡因喷雾的航空麻醉减弱了与呼吸道刺激相关的动脉血压和心率的变化，这通常会引起人体的心肺反射反应。静脉注射布比卡因和罗比卡因，一种新的局部麻醉剂，在大鼠体内引起动脉压力反射反应，抑制它们的毒性剂量。轻度呼吸性酸中毒时抑制作用不明显，呼吸性碱中毒时抑制作用减弱。

Inhaled of mechanical stimulation to the respiratory tracts could elicit several cardiopulmonary responses, includidng changes in blood pressure and heart rate as well as bronchoconstriction and so on. Since there are many receptors such as irritant receptors, stretch receptors and J-receptors in the respiratory tracts of humans, inhaled gases such as nitric oxide, inhalation of which recently inroduced in clinically for patients with pulmonary hypertension or acute respiratory distress syndrome, and nicotine smoke, which is very a popular problem, could elicit cariovascular changes. However there has been no study available as to these points. In the present studies, we aimed to examine how inhalation of gas as well as airway anesthesia affect the reflex responses and had the following results.1)In anesthetized dogs, nitric oxide (NO), 5ppm and 50ppm, did not cause any significant influence on arterial barorefex sensitivity, but significantly suppressed pulmonary arterial responses to hypoxemia.2)Cigarette smoking (nicotine of 0.1mg and 1mg with tar of 13mg) caused to constrict pial arterioles and venules observed using the cranial window in anesthetized rats. The effets seem to be in a concentration-dependent fashione, perhaps to be via nicotinic receptors, at least partly, and sympathetic activation by cigarette smoking.3)Airwayanesthesia using lidocaine's spray attenuated the changes in arterial blood pressure and heart rate associated with airway stimulation which usually causes cardiopulmonary reflex responses in humans.Intravenous administration of bupivacaine and ropivacaine, a new local anesthetic, caused arterial baroreflex responses to suppress in their toxic dose in rats. The supression was not augumented in the presence of mild respiratory acidosis, but atttenuated in the presence of respiratory alkalosis.