Kawakami Y, Menkes H A, DuBois A B
J Clin Invest. 1970 Jun;49(6):1237-51. doi: 10.1172/JCI106337.
A water-filled body plethysmograph was constructed to measure gas exchange in man. As compared to an air-filled plethysmograph, its advantages were greater sensitivity, less thermal drift, and no change from adiabatic to isothermal conditions after a stepwise change of pressure. When five subjects were completely immersed within it and were breathing to the ambient atmosphere, they had a normal heart rate, oxygen consumption, CO(2) output, and functional residual capacity. Pulmonary capillary blood flow ([unk]Qc) during and after Valsalva and Mueller maneuvers was calculated from measurements of N(2)O uptake. Control measurements of [unk]Qc were 2.58 liters/min per m(2) at rest and 3.63 liters/min per m(2) after moderate exercise. During the Valsalva maneuver at rest (intrapulmonary pressure: 24, SD 3.0, mm Hg), [unk]Qc decreased from a control of 2.58, SD 0.43, liters/min per m(2) to 1.62, SD 0.26, liters/min per m(2) with a decrease in pulmonary capillary stroke volume from a control of 42.4, SD 8.8, ml/stroke per m(2) to 25.2, SD 5.5, ml/stroke per m(2). After release of the Valsalva, there was an overshoot in [unk]Qc averaging +0.78, SD 0.41, liter/min per m(2) accompanied by a significant increase in heart rate. Similar changes occurred during and after the Valsalva following moderate exercise. During the Mueller maneuver at rest and after exercise, [unk]Qc, heart rate, and central stroke volume did not change significantly.
构建了一个充水式人体体积描记器来测量人体的气体交换。与充气式体积描记器相比,它的优点是灵敏度更高、热漂移更小,并且在压力逐步变化后不会从绝热状态转变为等温状态。当五名受试者完全浸入其中并向周围大气呼吸时,他们的心率、耗氧量、二氧化碳排出量和功能残气量均正常。通过测量氧化亚氮摄取量来计算瓦尔萨尔瓦动作和米勒动作期间及之后的肺毛细血管血流量([unk]Qc)。静息时[unk]Qc的对照测量值为每平方米2.58升/分钟,适度运动后为每平方米3.63升/分钟。静息时进行瓦尔萨尔瓦动作期间(肺内压:24,标准差3.0,毫米汞柱),[unk]Qc从对照值每平方米2.58,标准差0.43,升/分钟降至每平方米1.62,标准差0.26,升/分钟,肺毛细血管每搏量从对照值每平方米42.4,标准差8.8,毫升/搏降至每平方米25.2,标准差5.5,毫升/搏。瓦尔萨尔瓦动作解除后,[unk]Qc平均超调量为每平方米+0.78,标准差0.41,升/分钟,同时心率显著增加。适度运动后进行瓦尔萨尔瓦动作期间及之后也出现了类似变化。静息时和运动后进行米勒动作期间,[unk]Qc、心率和中心每搏量均无显著变化。