Liu Song-qiao, Chen Jing, Huang Ying-zi, Guo Feng-mei, Liu Ling, Yang Yi
Department of Critical Care Medicine, Zhong-Da Hospital and Medical College of Southeast University, Nanjing 210009, China.
Zhonghua Nei Ke Za Zhi. 2011 Nov;50(11):926-30.
To evaluate the value of dead space fraction (V(D)/V(T)) guided positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS).
Twenty-three intubated and mechanically ventilated patients with early ARDS were enrolled in the study. PEEP was titrated by lowest V(D)/V(T). Parameters of oxygenation and respiratory mechanics were observed.
PEEP titrated by lowest V(D)/V(T) and highest static lung compliance (C(Lst)) (P > 0.05) respectively, were lower than PEEP titrated by optimal oxygenation (P < 0.05), but there was no significant difference between lowest V(D)/V(T) and highest C(Lst) method. The V(D)/V(T) that ventilated on PEEP titrated by the lowest V(D)/V(T) decreased than its basal level. There was no difference significantly between the V(D)/V(T) that ventilated on PEEP elected by the other two methods with basal level (P > 0.05). The the ratio of arterial PO2 to the inspired oxygen fraction (PaO2/FiO2) ratios improved significantly than the baseline values in three ventilation strategies, and that ventilated on PEEP targeting the lowest V(D)/V(T) was lower than PEEP targeting optimal oxygenation. The plateau airway pressure that ventilated on PEEP targeting optimal oxygenation was higher than the other two methods. The functional residual capacity (FRC) of patients ventilated by PEEP targeting optimal oxygenation was increased than the lowest V(D)/V(T) and maximum C(Lst).
V(D)/V(T) could be one of the methods to titrate the optimal PEEP in patients with early ARDS. Optimal PEEP targeting the highest compliance in conjunction with the lowest dead space fraction indicated a maximum amount of effectively expanded alveoli.
评估死腔分数（V(D)/V(T)）指导下的呼气末正压（PEEP）在急性呼吸窘迫综合征（ARDS）中的价值。
23例早期ARDS且行气管插管机械通气的患者纳入本研究。通过最低V(D)/V(T)来滴定PEEP。观察氧合和呼吸力学参数。
分别通过最低V(D)/V(T)和最高静态肺顺应性（C(Lst)）滴定的PEEP（P>0.05）低于通过最佳氧合滴定的PEEP（P<0.05），但最低V(D)/V(T)和最高C(Lst)方法之间无显著差异。在通过最低V(D)/V(T)滴定的PEEP下通气时的V(D)/V(T)低于其基础水平。通过其他两种方法选择的PEEP通气时的V(D)/V(T)与基础水平之间无显著差异（P>0.05）。在三种通气策略中，动脉血氧分压与吸入氧分数之比（PaO2/FiO2）均较基线值显著改善，且在以最低V(D)/V(T)为目标的PEEP下通气时低于以最佳氧合为目标的PEEP。以最佳氧合为目标的PEEP通气时的平台气道压高于其他两种方法。以最佳氧合为目标的PEEP通气的患者的功能残气量（FRC）高于以最低V(D)/V(T)和最大C(Lst)为目标的PEEP。
V(D)/V(T)可作为滴定早期ARDS患者最佳PEEP的方法之一。以最高顺应性和最低死腔分数为目标的最佳PEEP表明有效扩张肺泡的数量最多。
