Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, USA.
Gastrointest Endosc. 2012 May;75(5):1062-7. doi: 10.1016/j.gie.2011.12.007. Epub 2012 Jan 31.
Cryotherapy is a method of endoscopic mucosal ablation that involves delivery of a cryogen to result in tissue destruction by extreme low temperature. Its effects are influenced by the dosage of cryogen and thawing of ice. There are limited data on the tissue effects of multiple freeze and thaw cycles of carbon dioxide (CO(2)) cryotherapy on GI tissues.
To investigate the extent of tissue injury due to escalating doses of CO(2) cryotherapy on the esophagus, stomach, and colon of pigs.
Animal experiment.
Varying doses of CO(2) cryotherapy with increasing number of freeze-thaw cycles were applied to each site. The animals were allowed to survive for 48 hours.
Depth of tissue injury assessed in blinded fashion by varying doses of cryotherapy on a defined area of porcine esophagus, stomach, and colon.
There was a dose-dependent relationship of CO(2) cryogen and depth of injury (P = .0001 and P = .002, respectively). In the stomach, the dose-response relationship was significant (P = .007), but the average grades of injury across the various doses were lower when compared with the esophagus at comparable cryogen doses (P = .0004). The estimated depth of tissue injury from the mucosal surface in the porcine esophagus and colon tissue ranged from 1.2 to 2.5 mm and 1.3 to 2.5 mm, respectively.
The study was performed in a normal porcine model.
There was a dose-dependent relationship between the dose of CO(2) cryotherapy and the depth of tissue injury in the porcine esophagus, stomach, and colon.
冷冻疗法是一种内镜下黏膜消融方法，通过输送冷冻剂导致组织在极低温度下破坏。其效果受冷冻剂剂量和冰的融化的影响。关于二氧化碳（CO2）冷冻疗法在胃肠道组织上多次冻融循环的组织效应，数据有限。
研究递增剂量 CO2 冷冻疗法对猪食管、胃和结肠组织造成的组织损伤程度。
动物实验。
在每个部位应用递增剂量的 CO2 冷冻疗法和增加的冻融循环次数。允许动物存活 48 小时。
通过对猪食管、胃和结肠的特定区域应用不同剂量的冷冻疗法，以盲法评估组织损伤的深度。
CO2 冷冻剂的剂量与损伤深度呈剂量依赖性关系（P =.0001 和 P =.002）。在胃中，剂量反应关系具有统计学意义（P =.007），但与可比冷冻剂量下的食管相比，各剂量下的平均损伤程度较低（P =.0004）。从猪食管和结肠组织的黏膜表面估计的组织损伤深度范围分别为 1.2 至 2.5 毫米和 1.3 至 2.5 毫米。
该研究在正常猪模型中进行。
CO2 冷冻疗法的剂量与猪食管、胃和结肠的组织损伤深度之间存在剂量依赖性关系。
