Meakin G, Jennings A D, Beatty P C, Healy T E
Royal Manchester Children's Hospital, Pendlebury.
Br J Anaesth. 1992 Apr;68(4):333-7. doi: 10.1093/bja/68.4.333.
We have determined the minimum fresh gas flow rate (VF) for use with the Ohmeda enclosed afferent reservoir breathing system (EAR) in 10 anaesthetized children breathing spontaneously. First, we determined the VF required to prevent rebreathing as detected by increased total ventilation (VE) and end-tidal carbon dioxide partial pressure. Second, we used a mathematical model to calculate the degree of rebreathing occurring at each VF. A VF equal to the predicted alveolar ventilation was sufficient to prevent clinically detectable rebreathing in all patients. From the model, no rebreathing occurred when VF/VE was 0.78 or more. We have shown previously that the EAR functions efficiently during controlled ventilation with a VF = 0.6 x weight 0.5. As this VF is slightly greater than the predicted alveolar ventilation, we suggest that the EAR may be used with a VF = 0.6 x weight 0.5 regardless of the mode of ventilation.
我们已确定了10名自主呼吸的麻醉儿童使用Ohmeda封闭式传入储气囊呼吸系统（EAR）时的最低新鲜气流速（VF）。首先，我们确定了通过增加的总通气量（VE）和呼气末二氧化碳分压检测到的防止重复呼吸所需的VF。其次，我们使用数学模型计算了每个VF时发生的重复呼吸程度。等于预测肺泡通气量的VF足以防止所有患者出现临床可检测到的重复呼吸。根据该模型，当VF/VE为0.78或更高时，不会发生重复呼吸。我们之前已经表明，在控制通气期间，当VF = 0.6×体重0.5时，EAR能有效发挥作用。由于该VF略大于预测的肺泡通气量，我们建议无论通气模式如何，EAR都可使用VF = 0.6×体重0.5。
