Anvari B, Motamedi M, Torres J H, Rastegar S, Orihuela E
Beckman Laser Institute and Medical Clinic, University of California, Irvine 92715.
Lasers Surg Med. 1994;14(4):386-95. doi: 10.1002/lsm.1900140411.
Effects of surface irrigation on the thermal response of tissue during laser irradiation are investigated. In particular, influence of temperature and flow rate of the irrigation fluid on the resulting temperature distributions and coagulation depths are studied. Intraluminal Nd:YAG laser irradiation of bovine muscle is performed in vitro for a fixed value of the irrigation flow rate while the irrigation temperature is varied, and for a fixed irrigation temperature while the irrigation flow rate is kept constant. Thermocouples are used to measure the temperatures within the tissue for various irradiation and irrigation conditions. Higher temperatures and deeper coagulation depths are achieved as the temperature of the irrigation fluid is increased. For sufficiently low values of irradiance and exposure time, the use of cold irrigation is shown to prevent or delay tissue carbonization. Beyond a critical irradiance and an exposure time, use of cold irrigation does not prevent tissue carbonization. Coagulation depths and temperature distributions are not affected by a change in the flow rate of laminar irrigation. Application of stagnant irrigation, however, results in an increase in coagulation depth. Results of this study suggest that the dominating mechanism of heat transfer during application of laminar irrigation is thermal diffusion as compared to the bulk motion of the fluid.
研究了表面灌溉对激光照射期间组织热响应的影响。特别地，研究了灌溉液的温度和流速对所得温度分布和凝固深度的影响。在体外对牛肌肉进行腔内钕：钇铝石榴石激光照射，灌溉流速固定而灌溉温度变化，以及灌溉温度固定而灌溉流速保持恒定。使用热电偶测量各种照射和灌溉条件下组织内的温度。随着灌溉液温度升高，可实现更高的温度和更深的凝固深度。对于足够低的辐照度和暴露时间值，表明使用冷灌溉可防止或延迟组织碳化。超过临界辐照度和暴露时间，使用冷灌溉不能防止组织碳化。层流灌溉流速的变化不会影响凝固深度和温度分布。然而，应用停滞灌溉会导致凝固深度增加。本研究结果表明，与流体的整体运动相比，层流灌溉应用期间传热的主导机制是热扩散。
