Gårdebäck M, Settergren G, Ohquist G, Tirén C
Department of Cardiothoracic Anaesthetics and Intensive Care, Karolinska Hospital, Stockholm, Sweden.
Acta Anaesthesiol Scand. 1995 Jul;39(5):599-604. doi: 10.1111/j.1399-6576.1995.tb04134.x.
Gastric tonometry was used to study the possible effect of dopexamine infusion on a low calculated intramucosal pH (pHi) as a sign of splanchnic ischemia. Measurements were made during surgery and for approximately 18 hours postoperatively on 19 non-selected adult patients undergoing valve replacement. Patients developing a postoperative pHi > 7.30 were randomized to receive dopexamine (2 micrograms.kg-1 min-1) or placebo in a double blind fashion. Eighteen patients were randomized, 10 to receive dopexamine and 8 to placebo. The calculated pHi remained unchanged for the first 2 hours in both groups. After 4 hours a significant (P < 0.05) decrease in pHi was noted in the dopexamine group which remained significantly below the placebo group during the monitoring period. The dopexamine treated patients had a significantly longer period of low pHi but the pH-gap i.e. the difference between arterial pH and pHi did not differ between the two groups. Patients with postoperative complications, defined as infections (2), myocardial infarction (1), single- (2) or multiple organ failure and death (1), did not have longer periods with pHi below 7.30. In these patients, however, a pH-gap > 0.12 occurred more often than in those without complications, indicating that an increased incidence of complications was related to a pH-gap > 0.12. It is our opinion that true mucosal ischemia is best detected by estimating the difference in carbon dioxide tension between arterial blood and mucosa. This can be expressed either directly as PCO2-gap (PtonCO2-PaCO2) or indirectly as pH-gap.
采用胃张力测定法研究多培沙明输注对计算得出的低黏膜内pH值（pHi）的可能影响，该低pHi值是内脏缺血的一个标志。对19例接受瓣膜置换术的非特定成年患者在手术期间及术后约18小时进行了测量。术后pHi>7.30的患者以双盲方式随机接受多培沙明（2微克·千克-1·分钟-1）或安慰剂治疗。18例患者被随机分组，10例接受多培沙明治疗，8例接受安慰剂治疗。两组在最初2小时内计算得出的pHi均保持不变。4小时后，多培沙明组的pHi显著降低（P<0.05），在监测期间一直显著低于安慰剂组。接受多培沙明治疗的患者pHi处于低水平的时间明显更长，但两组之间的pH差值（即动脉血pH值与pHi之间的差值）并无差异。术后出现并发症（定义为感染2例、心肌梗死1例、单器官或多器官功能衰竭及死亡1例）的患者，其pHi低于7.30的时间并未延长。然而，在这些患者中，pH差值>0.12的情况比无并发症的患者更常见，这表明并发症发生率增加与pH差值>0.12有关。我们认为，通过估计动脉血与黏膜之间二氧化碳张力的差异，能最好地检测到真正的黏膜缺血。这可以直接表示为PCO2差值（PtonCO2-PaCO2），也可以间接表示为pH差值。
