Brenner M, Shankel T, Wang N S, Waite T A, Wong H, Hamilton A, Tadir Y, Milner T, Boyajian J, Chung E, Tromberg B, Wilson A F, Berns M W
Department of Medicine, University of California Irvine Medical Center, Orange, California 92668, USA.
Am J Respir Crit Care Med. 1996 Mar;153(3):1136-40. doi: 10.1164/ajrccm.153.3.8630557.
Laser exposure of the pulmonary parenchyma during treatment of emphysema and other clinical indications causes acute lung injury. Animal investigations are needed to understand and control laser-induced lung injury. We hypothesized that lung injury is deeper from Nd:YAG laser exposures than CO2 exposures because of deeper penetration of Nd:YAG wavelength light. We compared the temporal evolution of histologic injury in rabbits resulting from continuous mode shallow CO2 and Nd:YAG laser pulmonary parenchymal exposures applied in rabbits. Forty-six New Zealand white (NZW) rabbits underwent treatment with CO2 laser (n=18), Nd:YAG laser (n=18), or sham thoracotomy control (n=10) to the visceral pleural surface using 1 min of exposure (5 watts, defocused to 70 W/cm2 power density for both lasers). Animals were killed at 0, 4, 7, 21, and 49 d after exposure. Lung injury, similar to that seen clinically in humans, developed in all laser-treated animals. Injury progressed from ischemia and vascular congestion, to edema and necrosis, followed by pleural and parenchymal fibrosis. The acute injury was qualitatively distinct and slightly deeper in CO2 than Nd:YAG-treated animals (p<0.02) despite the shallower depth of penetration of the CO2 laser. These findings may imply that higher absorption coefficient for CO2 laser energy results in greater focal temperatures and injury in the areas of direct exposure, and suggest that Nd:YAG laser exposure at these settings may cause shallower injury than CO2 lasers in humans undergoing clinical treatment.
在治疗肺气肿及其他临床适应症时，对肺实质进行激光照射会导致急性肺损伤。需要通过动物研究来了解并控制激光诱导的肺损伤。我们推测，由于Nd:YAG激光波长的光穿透更深，因此Nd:YAG激光照射导致的肺损伤比CO2激光照射更深。我们比较了连续模式下，对家兔肺实质进行浅部CO2激光和Nd:YAG激光照射后，家兔组织学损伤的时间演变情况。46只新西兰白兔接受了CO2激光治疗（n = 18）、Nd:YAG激光治疗（n = 18）或假开胸对照（n = 10），通过对脏层胸膜表面进行1分钟照射（5瓦，两种激光均散焦至70 W/cm2功率密度）。在照射后0、4、7、21和49天处死动物。所有接受激光治疗的动物均出现了与人类临床所见相似的肺损伤。损伤从缺血和血管充血发展为水肿和坏死，随后出现胸膜和实质纤维化。尽管CO2激光的穿透深度较浅，但CO2激光治疗的动物急性损伤在性质上有所不同，且比Nd:YAG激光治疗的动物稍深（p<0.02）。这些发现可能意味着，CO2激光能量的吸收系数较高，导致直接暴露区域的局部温度更高和损伤更大，这表明在这些设置下，Nd:YAG激光照射对接受临床治疗的人类造成的损伤可能比CO2激光浅。
