Steffey E P, Howland D
Am J Vet Res. 1977 Dec;38(12):1993-6.
The slow rate of change of inspired halothane concentration which results in a conventional large animal circle anesthetic delivery system when low carrier gas flow rates are used was confirmed, using a model system. To obtain a 63% change in inspired halothane concentration in the 32-L large animal circle anesthetic machine at fresh gas inflow rates of 3, 6, and 12 L/minute required 10.7, 5.3, and 2.7 minutes, respectively. At a given inflow rate, increasing the rebreathing bag size from 20 to 40 L prolonged the time for equilibration between the gas flowing into the anesthetic circuit and the inspired gas. The extent to which an adult horse further slowed the rate of rise of inspired anesthetic concentration was also demonstrated.
使用模型系统证实，当采用低载气流量时，吸入氟烷浓度的缓慢变化率会导致传统的大型动物环路麻醉输送系统出现这种情况。在32升大型动物环路麻醉机中，新鲜气体流入速率分别为3、6和12升/分钟时，要使吸入氟烷浓度发生63%的变化，分别需要10.7、5.3和2.7分钟。在给定的流入速率下，将再呼吸袋的尺寸从20升增加到40升，会延长流入麻醉回路的气体与吸入气体之间达到平衡的时间。还证明了成年马会进一步减缓吸入麻醉剂浓度上升速率的程度。
