Djoufack-Momo Shelly M, Amparan Ashlee A, Grunden Beverly, Boivin Gregory P-
Department of Community Health, Wright State University, Dayton, Ohio, USA.
J Am Assoc Lab Anim Sci. 2014 Jul;53(4):404-7.
CO₂ euthanasia is used widely for small laboratory animals, such as rodents. A common necessity in many animal research facilities is to euthanize mice in sequential batches. We assessed the effects of several variables on the time it took for CO₂ to dissipate within a chamber. Using standard euthanasia time, changes in flow rate were compared between a slow 15% fill rate for 7 min, and a slow 15% followed by a rapid 50% filling for a total of 5 min. Additional variables assessed included the effects of opening the lid after the completion of chamber filling, turning the chamber over after completion of filling, and the use and removal of a cage from within the chamber. For all trials, CO₂ levels in the chambers peaked between 50% and 80%. After the gas was turned off, the concentration of CO₂ dropped to below 10% COv within 2 min, except when the lid was left on the chamber, where concentration levels remained above 10% after 20 min. CO₂ dissipation was significantly faster when the chamber was turned upside down after filling. Significant interaction effects occurred among the factors of cage presence within the chamber, flow rate, and chamber position. Only leaving the lid on the chamber had any practical implication for delaying CO₂ dissipation. We recommend that users allow 2 min for CO₂ to clear from the chamber before subsequent euthanasia procedures, unless the chamber is manipulated to increase the dissipation rate.
二氧化碳安乐死法被广泛用于小型实验动物，如啮齿动物。在许多动物研究设施中，一个常见的需求是分批对小鼠实施安乐死。我们评估了几个变量对二氧化碳在舱室内消散所需时间的影响。使用标准安乐死时间，比较了两种流速变化的情况，一种是在7分钟内以缓慢的15%填充率，另一种是先以缓慢的15%填充，然后以快速的50%填充，总共5分钟。评估的其他变量包括在舱室填充完成后打开盖子的影响、填充完成后翻转舱室的影响，以及在舱室内使用和移除笼子的影响。在所有试验中，舱室内的二氧化碳水平在50%至80%之间达到峰值。关闭气体后，二氧化碳浓度在2分钟内降至10%以下，除非舱室盖子保持关闭，在这种情况下20分钟后浓度水平仍高于10%。填充后翻转舱室时，二氧化碳消散明显更快。舱室内笼子的存在、流速和舱室位置等因素之间存在显著的交互作用。只有保持舱室盖子关闭对延迟二氧化碳消散有实际影响。我们建议使用者在后续安乐死程序之前留出2分钟让二氧化碳从舱室中清除，除非对舱室进行操作以提高消散速度。
