Paramasivam Rupan, Kristensen Nickolai Malte, Ambrus Rikard, Stavsetra Marie, Ørntoft Mai-Britt, Madsen Anders Husted
Eur Surg Res. 2023 Dec 7. doi: 10.1159/000535525.
Healing is essential for successful colorectal surgery. Optimal microcirculation is needed to ensure this; however, this is only subjectively assessed by the surgeon. Laser Speckle Contrast Imaging (LSCI) is an objective non-contact, image-based method to quantify microcirculation in bowel ends. This study aimed to evaluate the application of LSCI in an open surgery porcine model, determine differences between normal and impaired microcirculation, and test the LSCI applicability to repeated measurements.
A midline laparotomy was made in ten healthy female pigs to expose the colon and small intestine. Subsequently, baseline measurements were conducted. A local arteria supplying the colonic or small intestine mesentery was clamped for 5 min. and LSCI measures were made again. After an hour's rest, LSCI measurements were done in two unaffected areas on the colon and the small intestine, and baseline values were recorded. Hypotension was induced with rapid bleeding and LSCI measurements were done. After the mean arterial blood pressure (MAP) dropped to 50-60 mmHg, norepinephrine infusion was started. At a stable MAP of 85-100 mmHg, LSCI measurements were repeated at 0 min. and 30 min. during continuous norepinephrine infusion.
Cross-clamping caused LSCI levels to drop equally in both the colon and small intestine by 60% in the entire the clamped zone. Compared to baseline, the microcirculation measured by LSCI in the unclamped adjacent transition zone was diminished by 33% and 40%, colon and small intestines, respectively. During hypotension due to bleeding, LSCI decreased as expected. When MAP was stabilized by norepinephrine infusion, LSCI values dropped further: compared to baseline, measurements decreased with 24% and 20% in colon and small intestines, respectively.
LSCI can be used as a quantitative, real-time, non-contact method to detect changes in the microcirculation during open intestinal surgery with large changes in microcirculation due to e.g., hypovolemic and norepinephrine infusion. It is simple to use and in contrast to the existing intraoperative microcirculation assessment techniques, LSCI stands out primarily for its elimination of the requirement for a dye. As our study has shown, this feature allows us to perform time-independent measurements and repeat them indefinitely in nearby regions without compromising the effectiveness of the method.
愈合对于结直肠手术的成功至关重要。为此需要最佳的微循环；然而，这仅由外科医生进行主观评估。激光散斑对比成像（LSCI）是一种客观的非接触式、基于图像的方法，用于量化肠端的微循环。本研究旨在评估LSCI在开放手术猪模型中的应用，确定正常和受损微循环之间的差异，并测试LSCI对重复测量的适用性。
对十只健康的雌性猪进行中线剖腹术，以暴露结肠和小肠。随后进行基线测量。夹闭供应结肠或小肠系膜的局部动脉5分钟，然后再次进行LSCI测量。休息一小时后，在结肠和小肠的两个未受影响区域进行LSCI测量，并记录基线值。通过快速出血诱导低血压并进行LSCI测量。在平均动脉血压（MAP）降至50 - 60 mmHg后，开始输注去甲肾上腺素。在MAP稳定在85 - 100 mmHg时，在持续输注去甲肾上腺素期间于0分钟和30分钟重复进行LSCI测量。
交叉夹闭导致结肠和小肠的LSCI水平在整个夹闭区域均同等下降60%。与基线相比，在未夹闭的相邻过渡区通过LSCI测量的微循环在结肠和小肠中分别减少了33%和40%。在出血导致的低血压期间，LSCI如预期那样下降。当通过输注去甲肾上腺素使MAP稳定时，LSCI值进一步下降：与基线相比，结肠和小肠的测量值分别下降了24%和20%。
LSCI可作为一种定量、实时、非接触的方法，用于检测开放肠道手术期间微循环的变化，这些变化是由例如低血容量和输注去甲肾上腺素引起的微循环大幅改变。它使用简单，与现有的术中微循环评估技术相比，LSCI的突出之处主要在于其无需染料。正如我们的研究所表明的，这一特性使我们能够进行与时间无关的测量，并在不影响方法有效性的情况下在附近区域无限期重复测量。
