Barbieri Riccardo, Triedman John K, Saul J Philip
Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
Am J Physiol Regul Integr Comp Physiol. 2002 Nov;283(5):R1210-20. doi: 10.1152/ajpregu.00127.2002.
Small negative changes of central volume reduce cardiac output without significant alterations of arterial blood pressure (ABP), suggesting an adequate regulatory response. Furthermore, evidence has arisen supporting a Bainbridge reflex (tachycardia with hypervolemia) in humans. To investigate these phenomena, multivariate autoregressive techniques were used to evaluate the beat-to-beat interactions between respiration, R-R interval, and ABP at six levels of decreased and increased central volume. With reductions of central volume below control, baroreflex and respiratory sinus arrhythmia gains were reduced, while with increases of volume above control, gains increased for the first two levels but decreased again at the highest volume level, suggesting the presence of a Bainbridge reflex in healthy human subjects. The mechanical influence of respiration on central venous pressure (CVP) had an unexpected shift in phase at the point of mild central hypervolemia, with the expected negative relation at lower volumes (inspiration lowers CVP) but a positive relation at higher volumes (inspiration raises CVP). We conclude that multivariate techniques can quantify the relations between a variety of respiratory and hemodynamic parameters, allowing for the in vivo assessment of complex cardiorespiratory interactions during manipulations of central volume. The results identify the presence of a Bainbridge reflex in humans and suggest that short-term cardiovascular control is optimized at mild hypervolemia.
中心血容量的微小负向变化会降低心输出量，而动脉血压（ABP）无显著改变，这表明存在充分的调节反应。此外，已有证据支持人类存在 Bainbridge 反射（血容量过多时心动过速）。为研究这些现象，采用多元自回归技术评估了在中心血容量降低和增加的六个水平下呼吸、R-R 间期和 ABP 之间的逐搏相互作用。中心血容量低于对照水平时，压力反射和呼吸性窦性心律不齐增益降低；而中心血容量高于对照水平时，前两个水平的增益增加，但在最高血容量水平时再次降低，这表明健康人类受试者存在 Bainbridge 反射。呼吸对中心静脉压（CVP）的机械影响在轻度中心血容量过多时出现了意外的相位变化，在较低血容量时呈现预期的负相关（吸气降低 CVP），而在较高血容量时呈现正相关（吸气升高 CVP）。我们得出结论，多元技术可以量化各种呼吸和血流动力学参数之间的关系，从而在体内评估中心血容量变化时复杂的心肺相互作用。结果表明人类存在 Bainbridge 反射，并提示短期心血管控制在轻度血容量过多时最为优化。
