Drake R E, Gabel J C
Center for Microvascular and Lymphatic Studies, University of Texas Medical School, Houston 77030.
Am J Physiol. 1991 Apr;260(4 Pt 2):R668-71. doi: 10.1152/ajpregu.1991.260.4.R668.
Lymphatic vessels are important in removing excess fluid from the intestines and preventing intestinal edema. In this study we used the relationship between intestinal lymph flow rate (QL) and lymphatic outflow pressure (PO) to analyze the flow from intestinal lymphatics in unanesthetized sheep. We cannulated intestinal lymphatic vessels in six anesthetized sheep. One to 3 days after the surgery, we measured QL as we increased PO in steps. We found no QL decrease until PO greater than 15 cmH2O, but QL decreased significantly for PO greater than 15 cmH2O and was decreased to zero at PO = 34 +/- 13 (SD) cmH2O. In three experiments, we used the pressure pulses generated by the active lymphatic pump to estimate the pump stroke volume and frequency. These data indicate that increases in lymphatic pumping prevented a QL decreased for PO less than 15 cmH2O and the QL decrease for PO greater than 15 cmH2O was associated with lymphatic pump failure. When we increased portal venous pressure from baseline (10.1 +/- 4.1 cmH2O) to 24.3 +/- 6.2 cmH2O, lymph flow increased, but it was much more sensitive to outflow pressure. These results are important because they indicate that the ability of the lymphatics to remove fluid from edematous intestines may be compromised by small increases in lymphatic outflow pressure.
淋巴管在清除肠道多余液体和预防肠道水肿方面起着重要作用。在本研究中，我们利用肠道淋巴液流速（QL）与淋巴流出压力（PO）之间的关系，分析了未麻醉绵羊肠道淋巴管的流量。我们在六只麻醉的绵羊身上插管至肠道淋巴管。手术后1至3天，我们在逐步增加PO的同时测量QL。我们发现，直到PO大于15 cmH2O时QL才会下降，但当PO大于15 cmH2O时QL显著下降，并且在PO = 34±13（标准差）cmH2O时降至零。在三个实验中，我们利用主动淋巴泵产生的压力脉冲来估计泵的冲程容积和频率。这些数据表明，淋巴泵的增加可防止PO小于15 cmH2O时QL下降，而PO大于15 cmH2O时QL下降与淋巴泵衰竭有关。当我们将门静脉压力从基线（10.1±4.1 cmH2O）增加到24.3±6.2 cmH2O时，淋巴流量增加，但它对流出压力更为敏感。这些结果很重要，因为它们表明淋巴管从水肿肠道清除液体的能力可能会因淋巴流出压力的小幅增加而受到损害。
