Hasaart T H, de Haan J
Eur J Obstet Gynecol Reprod Biol. 1985 Aug;20(2):121-9. doi: 10.1016/0028-2243(85)90125-x.
The effects of fetal breathing movements on the blood flow pattern in the common umbilical vein were studied in six chronically instrumented fetal lambs between 106 and 143 days gestation. Umbilical venous blood flow was measured with an electromagnetic flow transducer around the intra-abdominal common umbilical vein. Fetal breathing movements were recorded by means of an intratracheal catheter. During rapid irregular breathing movements instantaneous umbilical venous blood flow showed undulations with the frequency of the breathing movements. An inspiratory movement, characterized by a fall in tracheal pressure (mean +/- S.D. = 5.3 +/- 1.7 mmHg) was accompanied by a decrease in instantaneous umbilical venous blood flow (mean +/- S.D. = 10.5 +/- 2.8%). This decrease in umbilical blood flow during inspiration was accompanied by an increase in intra-abdominal pressure. A much greater decrease (mean +/- S.D. = 40.6 +/- 18.4%) in instantaneous umbilical venous blood flow occurred during deep inspiratory efforts (mean pressure drop +/- S.D. = 15.5 +/- 4.3 mmHg), accompanied by marked increases in intra-abdominal pressure. Isolated expiratory efforts resulted in an increase in both tracheal (mean +/- S.D. = 6.3 +/- 2.6 mmHg) and intra-abdominal pressure, while umbilical venous blood flow decreased (mean +/- S.D. = 33.5 +/- 21.3%). These observations show the great influence of fetal respiratory movements on the blood flow pattern in the common umbilical vein. The changes in instantaneous umbilical venous blood flow are possibly brought about by changes in intra-abdominal pressure.
在6只妊娠106至143天、长期植入仪器的胎羊中，研究了胎儿呼吸运动对脐静脉血流模式的影响。通过环绕腹内段脐静脉的电磁流量传感器测量脐静脉血流。通过气管内导管记录胎儿呼吸运动。在快速不规则呼吸运动期间，瞬时脐静脉血流随呼吸运动频率出现波动。以气管压力下降为特征的吸气运动（平均值±标准差=5.3±1.7 mmHg）伴随着瞬时脐静脉血流减少（平均值±标准差=10.5±2.8%）。吸气时脐血流的减少伴随着腹内压的升高。在深度吸气时（平均压力下降±标准差=15.5±4.3 mmHg），瞬时脐静脉血流出现更大幅度的减少（平均值±标准差=40.6±18.4%），同时腹内压显著升高。单独的呼气动作导致气管压力（平均值±标准差=6.3±2.6 mmHg）和腹内压升高，而脐静脉血流减少（平均值±标准差=33.5±21.3%）。这些观察结果表明胎儿呼吸运动对脐静脉血流模式有很大影响。瞬时脐静脉血流的变化可能是由腹内压的变化引起的。
