Griez E, van den Hout M A
J Behav Ther Exp Psychiatry. 1982 Mar;13(1):27-32. doi: 10.1016/0005-7916(82)90032-5.
The immediate effects of double inhalations of a 35% CO2-65% O2 mixture were studied on 12 subjects, all of them undergraduate students. For placebo control double inhalations of compressed air were administered to the same experimental subjects. In comparison, CO2/O2 inhalations were found to provoke significantly stronger autonomic reactions, viz, drops in heart rate and diastolic blood pressure. Reduction in subjective feeling of anxiety was observed with both CO2/O2 and air intake. On this parameter of subjective feeling the order in which the treatments were received interacted with the gas variable, i.e. CO2/O2 and air. The occurrence of a carry-over effect was indicated: Subjects having taken the placebo before CO2/O2 showed lower SUD scores than did those treated reversely.
对12名受试者（均为本科生）进行了研究，观察他们吸入35%二氧化碳-65%氧气混合物两次后的即时效应。作为安慰剂对照，对相同的实验对象给予两次压缩空气吸入。相比之下，发现吸入二氧化碳/氧气会引发明显更强的自主神经反应，即心率和舒张压下降。吸入二氧化碳/氧气和空气后，主观焦虑感均有所降低。在主观感觉这一参数上，接受治疗的顺序与气体变量（即二氧化碳/氧气和空气）相互作用。结果表明存在残留效应：在吸入二氧化碳/氧气之前服用安慰剂的受试者的主观不适感得分低于顺序相反的受试者。
