Steffey E P, Laster M J, Ionescu P, Eger E I, Emerson N
Department of Anesthesia, University of California-San Francisco 94143-0464, USA.
Anesth Analg. 1998 Jan;86(1):173-8. doi: 10.1097/00000539-199801000-00034.
Nonimmobilizers (inhaled compounds that do not suppress movement in response to a noxious stimulus) resemble anesthetics in their capacity to suppress memory, but unlike anesthetics, they can cause convulsions. Higher concentrations of nonimmobilizers may cause death, even with apparent suppression of convulsions by the concurrent administration of conventional inhaled anesthetics. We hypothesized that nonimmobilizers can depress ventilation and can cause death by adding to the depression of ventilation produced by conventional anesthetics. To test these hypotheses, we administered 1,2-dichlorohexafluorocyclobutane (2N) to four pigs anesthetized with desflurane. The addition of 2N decreased PaCO2 and tended to increase the slope of the ventilatory response to imposed increases in PETCO2. Limited results from study of two other nonimmobilizers (2,3-dichlorooctafluorobutane and perfluoropentane), in two pigs each, were consistent with the findings for 2N. However, experimental limitations (e.g., toxicity of 2,3-dichlorooctafluorobutane, and hypoxia from perfluoropentane) confound interpretation of these latter results. Our findings do not support our hypotheses--2N (and presumably all nonimmobilizers) seems to be a respiratory stimulant, not a depressant.
A new class of inhaled compounds, nonimmobilizers, allow tests of how inhaled anesthetics act. Nonimmobilizers may act like anesthetics (e.g., impair learning) or may not (e.g., do not prevent movement in response to a noxious stimulus). The present work shows that, unlike anesthetics,nonimmobilizers do not depress breathing.
非麻醉性气体（吸入后不会抑制对有害刺激的反应性运动的化合物）在抑制记忆的能力方面类似于麻醉剂，但与麻醉剂不同的是，它们会引起惊厥。即使同时使用传统吸入麻醉剂明显抑制了惊厥，高浓度的非麻醉性气体仍可能导致死亡。我们假设非麻醉性气体可抑制通气，并通过加重传统麻醉剂所产生的通气抑制作用而导致死亡。为验证这些假设，我们对4只接受地氟烷麻醉的猪给予1,2 - 二氯六氟环丁烷（2N）。加入2N后，动脉血二氧化碳分压（PaCO2）降低，并且对呼气末二氧化碳分压（PETCO2）升高所产生的通气反应斜率有增加趋势。对另外两种非麻醉性气体（2,3 - 二氯八氟丁烷和全氟戊烷）分别在2只猪身上进行的有限研究结果与2N的研究结果一致。然而，实验局限性（例如，2,3 - 二氯八氟丁烷的毒性以及全氟戊烷导致的低氧血症）使这些后期结果的解释变得复杂。我们的研究结果不支持我们的假设——2N（可能所有非麻醉性气体）似乎是一种呼吸兴奋剂，而非抑制剂。
一类新型的吸入化合物——非麻醉性气体，可用于测试吸入麻醉剂的作用方式。非麻醉性气体的作用可能类似于麻醉剂（例如，损害学习能力），也可能不同（例如，不阻止对有害刺激的反应性运动）。目前的研究表明，与麻醉剂不同，非麻醉性气体不会抑制呼吸。
