Versichelen L F, Bouche M P, Rolly G, Van Bocxlaer J F, Struys M M, De Leenheer A P, Mortier E P
Department of Anesthesia, Ghent University Hospital, Belgium.
Anesthesiology. 2001 Sep;95(3):750-5. doi: 10.1097/00000542-200109000-00030.
Insufficient data exist on the production of compound A during closed-system sevoflurane administration with newer carbon dioxide absorbents.
A modified PhysioFlex apparatus (Dräger, Lübeck, Germany) was connected to an artificial test lung (inflow at the top of the bellow approximately/= 160 ml/min CO2; outflow at the Y piece of the lung model approximately/= 200 ml/min, simulating oxygen consumption). Ventilation was set to obtain an end-tidal carbon dioxide partial pressure of approximately 40 mmHg. Various fresh carbon dioxide absorbents were used: Sodasorb (n = 6), Sofnolime (n = 6), and potassium hydroxide (KOH)-free Sodasorb (n = 7), Amsorb (n = 7), and lithium hydroxide (n = 7). After baseline analysis, liquid sevoflurane was injected into the circuit by syringe pump to obtain 2.1% end-tidal concentration for 240 min. At baseline and at regular intervals thereafter, end-tidal carbon dioxide partial pressure, end-tidal sevoflurane concentration, and canister inflow (T degrees(in)) and canister outflow (T degrees(out)) temperatures were measured. To measure compound Ainsp concentration in the inspired gas of the breathing circuit, 2-ml gas samples were taken and analyzed by capillary gas chromatography plus mass spectrometry.
The median (minimum-maximum) highest compound Ainsp concentrations over the entire period were, in decreasing order: 38.3 (28.4-44.2)* (Sofnolime), 30.1 (23.9-43.7) (KOH-free Sodasorb), 23.3 (20.0-29.2) (Sodasorb), 1.6 (1.3-2.1)* (lithium hydroxide), and 1.3 (1.1-1.8)* (Amsorb) parts per million (P < 0.01 vs. Sodasorb). After reaching their peak concentration, a decrease for Sofnolime, KOH-free Sodasorb, and Sodasorb until 240 min was found. The median (minimum-maximum) highest values for T degrees(out) were 39 (38-40), 40 (39-42), 41 (40-42), 46 (44-48), and 39 (38-41) degrees C (*P < 0.01 vs. Sodasorb), respectively.
With KOH-free (but sodium hydroxide [NaOH]-containing) soda limes even higher compound A concentrations are recorded than with standard Sodasorb. Only by eliminating KOH as well as NaOH from the absorbent (Amsorb and lithium hydroxide) is no compound A produced.
关于在使用新型二氧化碳吸收剂进行七氟醚密闭系统给药过程中化合物A的生成情况，现有数据不足。
将改良的PhysioFlex装置（德国吕贝克德尔格公司）连接至人工测试肺（风箱顶部流入约160 ml/min二氧化碳；肺模型Y形管处流出约200 ml/min，模拟耗氧量）。设置通气以获得约40 mmHg的呼气末二氧化碳分压。使用了各种新型二氧化碳吸收剂：碱石灰（n = 6）、Sofnolime（n = 6）、无氢氧化钾（KOH）的碱石灰（n = 7）、Amsorb（n = 7）和氢氧化锂（n = 7）。在基线分析后，通过注射泵将液体七氟醚注入回路，以在240分钟内获得2.1%的呼气末浓度。在基线及之后的固定时间间隔，测量呼气末二氧化碳分压、呼气末七氟醚浓度以及罐流入（Tin）和罐流出（Tout）温度。为测量呼吸回路吸入气体中的化合物A吸入浓度，采集2 ml气体样本并通过毛细管气相色谱 - 质谱联用仪进行分析。
在整个时间段内，化合物A吸入浓度的中位数（最小值 - 最大值）从高到低依次为：38.3（28.4 - 44.2）（Sofnolime）、30.1（23.9 - 43.7）（无KOH的碱石灰）、23.3（20.0 - 29.2）（碱石灰）、1.6（1.3 - 2.1）（氢氧化锂）和1.3（1.1 - 1.8）*（Amsorb）ppm（*与碱石灰相比，P < 0.01）。在达到峰值浓度后，发现Sofnolime、无KOH的碱石灰和碱石灰的浓度在240分钟内下降。Tout的中位数（最小值 - 最大值）最高值分别为39（38 - 40）、40（39 - 42）、41（40 - 42）、46（44 - 48）*和39（38 - 41）摄氏度（*与碱石灰相比，P < 0.01）。
与标准碱石灰相比，使用不含KOH但含氢氧化钠（NaOH）的碱石灰时，记录到的化合物A浓度更高。只有从吸收剂中同时去除KOH和NaOH（Amsorb和氢氧化锂）才不会产生化合物A。
