Cullen P M, Turtle M, Prys-Roberts C, Way W L, Dye J
Sir Humphry Davy Department of Anaesthesia, University of Bristol, Bristol Royal Infirmary, England.
Anesth Analg. 1987 Nov;66(11):1115-20.
Previous studies have shown that infusions of propofol, a new intravenous anesthetic, were associated with decreased arterial pressure and slow heart rates. To evaluate the role of baroreflex mechanisms in sustaining these conditions, the effects of two infusion rates of propofol (54 and 108 micrograms.kg-1.min-1) to supplement 66% nitrous oxide in oxygen anesthesia were studied in twelve ASA class I patients having a mean age of 34 years. Baroreflex control of heart rate was studied by perturbing the patients' arterial pressure with phenylephrine or sodium nitroprusside. Valsalva maneuvers were used to assess the response of the systemic arterial system. Steady state anesthesia at both infusion rates was not associated with decreased sensitivity of the baroreflex control of heart rate, but resetting of the reflex occurred to allow lower arterial pressures for a given heart rate than in the awake state. During propofol infusions at either rate, the diastolic pressure overshoot normally associated with the relief of raised airway pressure in the Valsalva maneuver was significantly reduced. It is concluded that propofol/nitrous oxide anesthesia is not associated with impairment of baroreflex sensitivity, but that central sympatholytic and/or vagotonic mechanisms enable low heart rates to be sustained despite decreased arterial pressures.
以往的研究表明，输注新型静脉麻醉药丙泊酚会导致动脉压下降和心率减慢。为了评估压力感受性反射机制在维持这些状态中的作用，我们对12例平均年龄34岁的美国麻醉医师协会（ASA）I级患者进行了研究，观察了丙泊酚两种输注速率（54和108微克·千克⁻¹·分钟⁻¹）在66%氧化亚氮-氧气麻醉中补充使用时的效果。通过用去氧肾上腺素或硝普钠干扰患者的动脉压来研究压力感受性反射对心率的控制。采用瓦尔萨尔瓦动作来评估体循环动脉系统的反应。两种输注速率下的稳态麻醉均与压力感受性反射对心率控制的敏感性降低无关，但反射发生了重新设定，使得在给定心率下的动脉压低于清醒状态。在以任一速率输注丙泊酚期间，瓦尔萨尔瓦动作中通常与气道压力升高缓解相关的舒张压过冲明显降低。得出的结论是，丙泊酚/氧化亚氮麻醉与压力感受性反射敏感性受损无关，但中枢性交感神经抑制和/或迷走神经兴奋机制使得尽管动脉压下降仍能维持低心率。
