Paulev P E, Honda Y, Sakakibara Y, Morikawa T, Tanaka Y, Nakamura W
Institute of Medical Physiology B, University of Copenhagen, Denmark.
Jpn J Physiol. 1988;38(4):507-17. doi: 10.2170/jjphysiol.38.507.
With a computerized impedance cardiograph we measured stroke volume (sv), cardiac output and heart rate (HR) in four men, during apnea with positive or negative intrapulmonic pressure (i.e., Valsalva and Mueller maneuver) in air. During Valsalva maneuvers the sv was reduced, and the compensatory rise in HR failed to keep the cardiac output at the control level before apnea. During both types of apnea, the diastolic pressure was increased as was the total peripheral resistance (TPR). The vasoconstriction and tachycardia during Valsalva maneuvers can be explained as a sino-aortic baroreceptor phenomenon in man. The smaller changes occurring during Mueller maneuvers result in no change in the transmural arterial pressure in the thorax, compared to the control level. Thus, without a stimulus there is no change in heart rate. The alveolar oxygen uptake and carbon dioxide elimination during apnea at total lung capacity was much larger than in the control phase before both types of apnea. The arteriolar vasoconstriction with increased TPR during the Valsalva apnea, was accompanied by a reduction in the stroke work of the left ventricle to approximately 50% of the work in the control phase.
我们使用计算机化阻抗心动描记仪，在空气中进行正性或负性肺内压（即瓦尔萨尔瓦动作和米勒动作）的屏气期间，测量了四名男性的每搏输出量（sv）、心输出量和心率（HR）。在瓦尔萨尔瓦动作期间，每搏输出量降低，而心率的代偿性升高未能使心输出量维持在屏气前的对照水平。在两种类型的屏气期间，舒张压均升高，总外周阻力（TPR）也升高。瓦尔萨尔瓦动作期间的血管收缩和心动过速可解释为人类的窦主动脉压力感受器现象。与对照水平相比，米勒动作期间发生的较小变化不会导致胸内跨壁动脉压的改变。因此，没有刺激时心率不会改变。在肺总量屏气期间的肺泡氧摄取和二氧化碳排出量比两种类型屏气前的对照阶段要大得多。瓦尔萨尔瓦屏气期间伴随总外周阻力增加的小动脉血管收缩，同时左心室的搏功减少至对照阶段功的约50%。
