1. In nine chronically catheterized fetuses in which all lung liquid was drained continuously from the time of surgery, the effects of continuous drainage of fetal urine for 1 week on fetal renal function, lung liquid production and salt and water balance were studied. Fetal wellbeing, as judged by fetal growth, urinary osmolality, blood gas status, arterial pressure and heart rate, was not adversely affected by urine drainage. The ewes, however, drank more water when fetal urine was drained. Thus. fetal plasma and urinary osmolalities declined (P < 0.25 and P < 0.05). 2. Fetal glomerular filtration rate fell from 75 +/- 4 ml kg-1 h-1 (+/- S.E.M., n = 9) before drainage to 54 +/- 7 ml kg-1 h-1 after drainage (n = 7; P < 0.005), and fetal renal sodium excretion also declined (P < 0.05). However, the excretion of sodium in lung liquid did not decrease and the fetal renin-angiotensin system was not activated. Fetal extracellular volume (561 +/- 44 ml kg-1, n = 7) and the calculated net sodium transfer (0.76 mmol kg-1 h-1, n = 6) and fluid transfer (15 +/- 2 ml kg-1 h-1, n = 8) to the fetus did not change. 3. It is concluded that overall fetal salt and water balance were maintained when all fetal urine and lung liquid were drained from fetal sheep in late gestation. Since drainage of urine and lung liquid considerably reduced the amniotic and allantoic fluids, transfer across the placenta and extraplacental membranes was able to compensate for the absence of these fluids. In response to the loss of sodium during drainage, fetal renal sodium conservation was about 11% of the total sodium conservation by the materno-fetal unit.
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机译:1.对从手术开始就连续排空所有肺液的9例慢性导尿胎儿,研究了连续排尿1周对胎儿肾脏功能,肺液产生以及盐和水平衡的影响。通过胎儿生长,尿渗透压,血气状态,动脉压和心率判断的胎儿健康不受排尿的不利影响。但是,排干胎儿尿液时,母羊会喝更多的水。从而。胎儿血浆和尿渗透压降低(P <0.25和P <0.05)。 2.胎儿肾小球滤过率从引流前的75 +/- 4 ml kg-1 h-1(+/- SEM,n = 9)降至引流后的54 +/- 7 ml kg-1 h-1(n = 7; P <0.005),胎儿肾钠排泄也下降(P <0.05)。但是,肺液中钠的排泄并没有减少,胎儿肾素-血管紧张素系统也未激活。胎儿细胞外体积(561 +/- 44 ml kg-1,n = 7)和计算出的净钠转移量(0.76 mmol kg-1 h-1,n = 6)和液体转移(15 +/- 2 ml kg- 1 h-1,n = 8)胎儿没有改变。 3.结论是,在妊娠后期从胎羊中排出所有的胎儿尿液和肺液时,总体的胎儿盐和水平衡得以维持。由于尿液和肺液的排出大大减少了羊水和尿囊液,因此通过胎盘和胎盘外膜的转移能够弥补这些液体的缺乏。由于引流过程中钠的流失,胎儿肾脏钠的保留量约为母胎单位总钠保留量的11%。
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