TRANSCAPILLARY FLUID SHIFTS IN TISSUES OF THE HEAD AND NECK DURING AND AFTER SIMULATED MICROGRAVITY
TRANSCAPILLARY FLUID SHIFTS IN TISSUES OF THE HEAD AND NECK DURING AND AFTER SIMULATED MICROGRAVITY
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DOI：
10.1152/jappl.1991.71.6.2469
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发表时间：
1991-12-01
影响因子：
3.3
通讯作者：
CRENSHAW, A
中科院分区：
文献类型：
--
作者：
PARAZYNSKI, SE;HARGENS, AR;CRENSHAW, A
为了了解微重力条件下面部浮肿的发生机制、程度和时间进程，7名男性受试者头部向下倾斜6度，持续8h，直接测量倾斜前、倾斜中和倾斜后的4种Starling跨毛细血管压力。头低位倾斜(HDT)导致面部水肿和下唇微血管压显著升高：毛细血管压从HDT前的27.7+/-1.5 mm Hg(平均值+/-SE)增加到倾斜结束时的33.9+/-1.7 mm Hg。颈部皮下和肌肉间质液压力也因HDT而增加，而间质液体胶体渗透压保持不变。血浆胶体渗透压在卧床后4h显著下降(卧床前为21.5+/-1.5 mm Hg，卧床前为18.2+/-1.9 mm Hg)，提示卧床期间心脏和足部毛细血管床由液体滤过向吸收转变。卧床4小时后，唇部微血管压(毛细血管和小静脉压)仍显著高于基线值5-8毫米汞柱。卧床期间，尿量为126.5毫升/小时，而对照组为46.7ml/小时。这些结果表明，HDT引起的面部水肿主要是由毛细血管压升高和血浆胶体渗透压降低引起的。心脏水平以上的间质液体压力的负值对直立状态下维持组织液体平衡也有一定的意义。
To understand the mechanism, magnitude, and time course of facial puffiness that occurs in microgravity, seven male subjects were tilted 6-degrees head-down for 8 h, and all four Starling transcapillary pressures were directly measured before, during, and after tilt. Head-down tilt (HDT) caused facial edema and a significant elevation of microvascular pressures measured in the lower lip: capillary pressures increased from 27.7 +/- 1.5 mmHg (mean +/- SE) pre-HDT to 33.9 +/- 1.7 mmHg by the end of tilt. Subcutaneous and intramuscular interstitial fluid pressures in the neck also increased as a result of HDT, whereas interstitial fluid colloid osmotic pressures remained unchanged. Plasma colloid osmotic pressure dropped significantly by 4 h of HDT (21.5 +/- 1.5 mmHg pre-HDT to 18.2 +/- 1.9 mmHg), suggesting a transition from fluid filtration to absorption in capillary beds between the heart and feet during HDT. After 4 h of seated recovery from HDT, microvascular pressures in the lip (capillary and venule pressures) remained significantly elevated by 5-8 mmHg above baseline values. During HDT, urine output was 126.5 ml/h compared with 46.7 ml/h during the control baseline period. These results suggest that facial edema resulting from HDT is caused primarily by elevated capillary pressures and decreased plasma colloid osmotic pressures. The negativity of interstitial fluid pressures above heart level also has implications for maintenance of tissue fluid balance in upright posture.