Background Positive end-expiratory pressure (PEEP) is used to optimize oxygenation by preventing alveolar collapse. However, PEEP can potentially decrease cardiac output through cardiopulmonary interactions. The effect of PEEP on cardiac output during cardiopulmonary resuscitation (CPR) is not known. Methods This was a preclinical randomized, controlled, animal study conducted in an animal research facility on 25 Landrace-Yorkshire pigs. After inducing cardiac arrest, CPR was performed with LUCAS 3. During CPR, pigs were ventilated at a PEEP of 0, 5, 10, 15, 20 cmH 2 O (randomly determined via lottery) for 9 min. Cardiac output, obtained via ultrasound dilution, and PaO 2 were measured, and oxygen delivery calculated for each PEEP. Results A mixed-effects repeated-measures analysis of variance was used to compare the baseline value adjusted mean cardiac output, PaO 2 , and oxygen delivery between PEEP groups. Least significant difference test was used to conduct pairwise comparisons between PEEP groups. To determine optimum PEEP, Gaussian mixture model was applied to the adjusted means of cardiac output and oxygen delivery. Increasing PEEP to 10 and higher resulted in significant declines in cardiac output. A PEEP of 15 and higher resulted in significant declines in oxygen delivery. As PEEP was increased from 0 to 20, PaO 2 increased significantly. Gaussian mixture model identified the 0–5 PEEP group as providing optimal cardiac output and oxygen delivery, with PEEP of 5 providing the highest oxygen delivery. Conclusions A PEEP of 0–5 resulted in the optimal oxygen delivery and cardiac output during CPR, with PEEP of 5 resulting in higher oxygen delivery, and a slightly lower, statistically insignificant cardiac output than PEEP of 0.

中文翻译：

---

心肺复苏过程中呼气末正压对心输出量和氧供的影响

背景 呼气末正压 (PEEP) 用于通过防止肺泡塌陷来优化氧合。然而，PEEP 可能会通过心肺相互作用降低心输出量。PEEP 对心肺复苏 (CPR) 期间心输出量的影响尚不清楚。方法 这是在动物研究设施中对 25 头长白猪约克夏猪进行的临床前随机对照动物研究。诱导心脏骤停后，使用 LUCAS 3 进行 CPR。在 CPR 期间，猪以 0、5、10、15、20 cmH 2 O（通过抽签随机确定）的 PEEP 通气 9 分钟。测量通过超声稀释获得的心输出量和 PaO 2 ，​​并计算每个 PEEP 的氧气输送量。结果 使用混合效应重复测量方差分析比较基线值调整后的平均心输出量、PaO 2 和 PEEP 组之间的氧气输送。最小显着差异检验用于进行 PEEP 组之间的成对比较。为了确定最佳 PEEP，高斯混合模型应用于调整后的心输出量和氧气输送方式。将 PEEP 增加到 10 或更高会导致心输出量显着下降。15 及更高的 PEEP 导致氧气输送显着下降。随着 PEEP 从 0 增加到 20，PaO 2 显着增加。高斯混合模型确定 0-5 PEEP 组提供最佳的心输出量和氧气输送，PEEP 为 5 提供最高的氧气输送。