Blood vessel burst pressures were simulated and predicted for sealing and cutting of vessels in a two-step process, using low (<25 W), medium (∼100 W), and high (200 W) power lasers at a wavelength of 1470 nm. Monte Carlo optical transport, heat transfer, Arrhenius integral tissue damage simulations, and vessel pressure equations were utilized. The purpose of these studies was to first validate the numerical model by comparison with experimental results (for low and medium power) and then to use the model to simulate parameters that could not be experimentally tested (for high power). The goal was to reduce the large range of parameters (power, irradiation time, and linear beam dimensions) to be tested in future experiments, for achieving short vessel sealing/cutting times, minimal bifurcated seal zones (BSZ), and high vessel burst pressures. Blood vessels were compressed to 400 μm thickness. A wide range of linear beam profiles (1-5 mm widths and 8-9.5 mm lengths), incident powers (20-200 W) and clinically relevant irradiation times (0.5-5.0 s) were simulated and peak seal and cut temperatures as well as thermal seal zones, ablation zones, and BSZ computed. A simplistic mathematical expression was used to estimate vessel burst pressures based on seal width. Optimal low-power parameters were: 24W/5s/8 × 2 mm (sealing) and 24W/5s/8x1mm (cutting), yielding a BSZ of 0.4 mm, corresponding to experimental burst pressures of ∼450 mmHg. Optimal medium-power parameters were: 90W/1s/9.5x3mm (sealing) and 90W/1s/9.5x1mm (cutting), yielding a BSZ of 0.9 mm for burst pressures of ∼1300 mmHg. Simulated only optimal high-power parameters were: 200W/0.5s/9x3 mm (sealing) and 200W/0.5s/9x1mm (cutting), yielding a BSZ of 0.9 mm and extrapolated to predict a seal strength of ∼1300 mmHg. All lasers produced seal zones between 0.4-1.5 mm, corresponding to high vessel burst pressures of 300-1300 mmHg (well above normal systolic blood pressure of 120 mmHg). Higher laser powers enable shorter sealing/cutting times and higher vessel strengths.

中文翻译：

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红外激光封切血管的计算模拟

使用波长为 1470 nm 的低 (<25 W)、中 (~100 W) 和高 (200 W) 激光，模拟和预测血管爆裂压力，用于在两步过程中密封和切割血管. 蒙特卡罗光学传输、热传递、Arrhenius 积分组织损伤模拟和血管压力方程被使用。这些研究的目的是首先通过与实验结果（低功率和中等功率）比较来验证数值模型，然后使用该模型模拟无法通过实验测试的参数（高功率）。目标是减少未来实验中要测试的大量参数（功率、辐照时间和线性光束尺寸），以实现较短的容器密封/切割时间、最小的分叉密封区 (BSZ) 和高容器爆破压力. 血管被压缩至 400 μm 厚。模拟了广泛的线性光束轮廓（1-5 mm 宽度和 8-9.5 mm 长度）、入射功率（20-200 W）和临床相关照射时间（0.5-5.0 s），以及峰值密封和切割温度作为热密封区、消融区和 BSZ 计算。使用一个简单的数学表达式来估计基于密封宽度的容器爆破压力。最佳低功率参数为：24W/5s/8 × 2 mm（密封）和 24W/5s/8x1mm（切割），产生 0.4 mm 的 BSZ，对应于 ~450 mmHg 的实验爆破压力。最佳中功率参数为：90W/1s/9.5x3mm（密封）和 90W/1s/9.5x1mm（切割），在 ∼1300 mmHg 的爆破压力下产生 0.9 mm 的 BSZ。仅模拟出最佳大功率参数为：200W/0.5s/9x3 mm（密封）和200W/0。5s/9x1mm（切割），产生 0.9 mm 的 BSZ 并推断预测密封强度为 ~1300 mmHg。所有激光产生的密封区域都在 0.4-1.5 mm 之间，对应于 300-1300 mmHg 的高血管爆裂压力（远高于 120 mmHg 的正常收缩压）。更高的激光功率可缩短密封/切割时间并提高容器强度。