MacDonald P H, Dinda P K, Beck I T, Mercer C D
Department of Surgery, Queen's University, Kingston, Ontario, Canada.
Surg Gynecol Obstet. 1993 May;176(5):451-8.
The intraoperative evaluation of intestinal ischemia and viability is often subjective and unreliable. The results of recent reports of pulse and surface oximetry have suggested that these techniques may be useful in assessing intestinal blood flow. In the current study, we evaluated and compared the ability of intestinal tissue oxygen saturation (as measured by pulse oximetry) and intestinal surface oxygen tension (as measured by surface oximetry) to determine the actual intestinal tissue blood flow (as measured with a radiolabeled microsphere technique). In five dogs, tissue oxygen saturation, surface oxygen tension and blood flow of the proximal and distal parts of the small intestine were measured under basal conditions. A clamp placed around the root of the superior mesenteric artery was then tightened to decrease the blood flow through this artery (as measured by an ultrasonic flow probe) by 50 percent and then by 75 percent, repeating all measurements after each reduction. The two consecutive reductions in superior mesenteric artery blood flow resulted in an average 54 and 76 percent reduction in tissue blood flow, respectively. As a result of these reductions in tissue blood flow, the average intestinal tissue oxygen saturation (percentage), as determined by pulse oximetry, decreased significantly from a basal value of 93 +/- 1 to 83 +/- 1 (p < 0.05) and then to 76 +/- 1 (p < 0.05) with the two progressive blood flow reductions. Intestinal surface oxygen tension decreased more steeply, from a basal value of 97 +/- 1 to 80 +/- 6 (p < 0.05) and then to 64 +/- 7 millimeters of mercury (p < 0.05) with the same two reductions in tissue blood flow. Both techniques were capable of estimating tissue blood flow, but pulse oximetry was quicker and simpler to use. We conclude that the pulse oximeter has the potential to be of value in the intraoperative assessment of intestinal blood flow.
术中对肠缺血和活力的评估往往主观且不可靠。近期有关脉搏和表面血氧饱和度测定的报告结果表明，这些技术可能有助于评估肠血流。在本研究中，我们评估并比较了肠组织氧饱和度（通过脉搏血氧饱和度测定法测量）和肠表面氧张力（通过表面血氧饱和度测定法测量）确定实际肠组织血流（通过放射性微球技术测量）的能力。在五只狗身上，在基础条件下测量小肠近端和远端的组织氧饱和度、表面氧张力和血流。然后收紧置于肠系膜上动脉根部的夹子，使通过该动脉的血流（通过超声血流探头测量）减少50%，然后再减少75%，每次血流减少后重复所有测量。肠系膜上动脉血流的两次连续减少分别导致组织血流平均减少54%和76%。由于组织血流的这些减少，通过脉搏血氧饱和度测定法确定的平均肠组织氧饱和度（百分比）从基础值93±1显著降至83±1（p<0.05），然后随着血流的两次逐步减少降至76±1（p<0.05）。肠表面氧张力下降更为陡峭，在组织血流同样减少两次的情况下，从基础值97±1降至80±6（p<0.05），然后降至64±7毫米汞柱（p<0.05）。两种技术都能够估计组织血流，但脉搏血氧饱和度测定法使用起来更快、更简单。我们得出结论，脉搏血氧仪在术中评估肠血流方面可能具有价值。
