神经重症与应激性溃疡课件.ppt

* * * Parietal cell 胃壁细胞 G cell 分泌胃泌素的细胞 ECL cell 類肠嗜铬细胞( ECL cell ) 分泌的组织胺( histamine ) 可刺激壁细胞分泌胃酸.  Chief cell又称为胃酶细胞，数量较多主要分布于胃底的中下部，胞体呈圆柱状，胞核圆形 ?。 总所周知，胃内pH4是预防应激性溃疡的关键，而保持胃内pH6则是治疗上消化道出血的关键。 * Slide18. IV PPIs As you can see, day three, 4.2% of the PPI group, but if you looked at day 7 and day 30, there is only a small incremental increase in rebleeding rates. Most rebleeding occurs in the first 72 hours after endoscopic hemostasis. This is very important for surgeons, because there may be a question at day 7 or day 30, but most bleeding will occur by day 3; the same thing in the placebo arm. Here is that classic 20% rebleed rate. It only jumps to 21.7% after another 4 days and up to only 22.5% by 30 days. The most important time period, which is the 72-hour period postendoscopy. In the PPI group, only 4.2% of patients rebled vs in the placebo group the classic 20% rebleed rate. This was statistically significant. At day 7, also statistically significant, 5.8 vs 21.7 and, again, statistically significant at 30 days, rebleed rate of 6.7 in the PPI group and 22.5% in the placebo group. So, as opposed to H2-blockers, which unfortunately are the most common form of medication we use in the acute bleeder in the United States, PPIs do reduce the rate of recurrent bleeding. They decrease the need for endoscopic retreatment. They decrease blood transfusion requirement and they shorten the length of hospitalization by over a day. * 血小板的聚集反应对pH高度敏感，pH的轻微下降使 聚集率显著降低 pH5.9以下时，血小板聚集被完全抑制，聚集率为0。 再次强调pH6以上与pH6以下的显著差异 * 该图说明胃蛋白酶在酸性环境中活性强，两个最适pH分别为pH1~1.6之间 和pH3.4，但pH超过4后立见胃酶活性的几乎垂直下降 据此有人主张，上消化道出血时将胃内pH升至4以上即可，但图中可见, 此时胃酶活性虽很低，但仍具崔化能力,pH6以上才能使其活性完全丧失 * 近中性不环境中，胃酶失活，不影响血小板聚集 酸性环境中，胃酶有活性，可使因酸性而开始解聚的血小板进一步解聚增多（**P0.01与单独酸性环境对比） 实验所用酸性环境为pH4.8，说明将胃内pH升至4以上仍不够理想 * pH6以上止血反应尚能较慢进行，pH6以下则显著受阻，CT为凝血时间。 上消化道出血初期，由于血液的缓冲作用，在血管破损的局部pH接近中性,有利止血，随着胃排空，局部酸度将逐渐升高，阻碍止血过程 。 * 治疗目标：一是胃内pH6以上，二是持续维持。因为任何泌酸反跳都可 能导致再出血发生而使治疗失败 胃酸的分泌 胃酸分泌的调控 控制胃内PH值药物 抗酸剂 制酸剂 H2受体阻滞剂(H2RA) 胃泌素受体拮抗剂－谷丙胺 M