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首页> 外文期刊>American Journal of Physiology >Evidence for central venous pressure resetting during initial exposure to microgravity.
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Evidence for central venous pressure resetting during initial exposure to microgravity.

机译：初次暴露于微重力时中心静脉压复位的证据。

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We measured central venous pressure (CVP); plasma volume (PV); urine volume rate (UVR); renal excretion of sodium (UNa); and renal clearances of creatinine, sodium, and osmolality before and after acute volume infusion to test the hypothesis that exposure to microgravity causes resetting of the CVP operating point. Six rhesus monkeys underwent two experimental conditions in a crossover counterbalance design: 1) continuous exposure to 10 degrees head-down tilt (HDT) and 2) a control, defined as 16 h/day of 80 degrees head-up tilt and 8 h prone. After 48 h of exposure to either test condition, a 120-min course of continuous infusion of isotonic saline (0.4 ml. kg(-1). min(-1) iv) was administered. Baseline CVP was lower (P = 0.011) in HDT (2.3 +/- 0.3 mmHg) compared with the control (4.5 +/- 1.4 mmHg) condition. After 2 h of saline infusion, CVP was elevated (P = 0.002) to a similar magnitude (P = 0.485) in HDT (DeltaCVP = 2.7 +/- 0.8 mmHg) and control (DeltaCVP = 2.3 +/- 0.8 mmHg) conditions and returned to preinfusion levels 18 h postinfusion in both treatments. PV followed the same pattern as CVP. The response relationships between CVP and UVR and between CVP and UNa shifted to the left with HDT. The restoration of CVP and PV to lower preinfusion levels after volume loading in HDT compared with control supports the notion that lower CVP during HDT may reflect a new operating point about which vascular volume is regulated. These results may explain the ineffective fluid intake procedures currently employed to treat patients and astronauts.
机译：我们测量了中心静脉压（CVP）。血浆体积（PV）;尿量率（UVR）;肾钠排泄（UNa）;急性体积输注前后肌酐，钠和重量摩尔渗透压浓度的肾脏清除率，以检验以下假设：微重力暴露会导致CVP工作点复位。六只恒河猴在交叉配重设计中经历了两种实验条件：1）连续暴露于10度的头部向下倾斜（HDT）和2）对照，即每天16小时80度的头部向上倾斜和8 h俯卧。在暴露于任何一种测试条件下48小时后，进行120分钟的等渗盐水连续输注过程（0.4 ml。kg（-1）。min（-1）iv）。与对照组（4.5 +/- 1.4 mmHg）相比，HDT（2.3 +/- 0.3 mmHg）的基线CVP较低（P = 0.011）。盐水注入2小时后，在HDT（DeltaCVP = 2.7 +/- 0.8 mmHg）和对照（DeltaCVP = 2.3 +/- 0.8 mmHg）的条件下，CVP升高（P = 0.002）至相似的幅度（P = 0.485）。两种治疗均在输注后18小时恢复到输液前水平。 PV遵循与CVP相同的模式。 HDT使CVP和UVR之间以及CVP和UNa之间的响应关系向左移动。与对照组相比，HDT中的容积负荷后，CVP和PV恢复至较低的输注前水平支持了以下观念：HDT期间较低的CVP可能反映了调节血管容量的新操作点。这些结果可能解释了目前用于治疗患者和宇航员的无效液体摄入程序。

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