Department of Anaesthesiology and Intensive Care Medicine, Medical University of Innsbruck, Innsbruck, Austria.
Department of Radiology, Medical University of Innsbruck, Innsbruck, Austria.
Am J Physiol Lung Cell Mol Physiol. 2023 Jun 1;324(6):L879-L885. doi: 10.1152/ajplung.00235.2022. Epub 2023 May 16.
In pressure-controlled ventilation (PCV), a decelerating gas flow pattern occurs during inspiration and expiration. In contrast, flow-controlled ventilation (FCV) guarantees a continuous gas flow throughout the entire ventilation cycle where the inspiration and expiration phases are simply performed by a change of gas flow direction. The aim of this trial was to highlight the effects of different flow patterns on respiratory variables and gas exchange. Anesthetized pigs were ventilated with either FCV or PCV for 1 h and thereafter for 30 min each in a crossover comparison. Both ventilation modes were set with a peak pressure of 15 cmHO, positive end-expiratory pressure of 5 cmHO, a respiratory rate of 20/min, and a fraction of inspired oxygen at 0.3. All respiratory variables were collected every 15 min. Tidal volume and respiratory minute volume were significantly lower in FCV ( = 5) compared with PCV ( = 5) animals [4.6 vs. 6.6, MD -2.0 (95% CI -2.6 to -1.4) mL/kg; < 0.001 and 7.3 vs. 9.5, MD -2.2 (95% CI -3.3 to -1.0) L/min; = 0.006]. Notwithstanding these differences, CO-removal as well as oxygenation was not inferior in FCV compared with PCV. Mechanical ventilation with identical ventilator settings resulted in lower tidal volumes and consecutive minute volume in FCV compared with PCV. This finding can be explained physically by the continuous gas flow pattern in FCV that necessitates a lower alveolar pressure amplitude. Interestingly, gas exchange was comparable in both groups, which is suggestive of improved ventilation efficiency at a continuous gas flow pattern. This study examined the effects of a continuous (flow-controlled ventilation, FCV) vs. decelerating (pressure-controlled ventilation, PCV) gas flow pattern during mechanical ventilation. It was shown that FCV necessitates a lower alveolar pressure amplitude leading to reduced applied tidal volumes and consequently minute volume. Notwithstanding these differences, CO-removal as well as oxygenation was not inferior in FCV compared with PCV, which is suggestive of improved gas exchange efficiency at a continuous gas flow pattern.
在压力控制通气（PCV）中，吸气和呼气过程中会出现减速气流模式。相比之下，流量控制通气（FCV）可确保整个通气周期内持续的气流，其中吸气和呼气阶段仅通过改变气流方向来完成。本试验的目的是强调不同气流模式对呼吸变量和气体交换的影响。麻醉猪分别用 FCV 或 PCV 通气 1 小时，然后交叉比较各通气 30 分钟。两种通气模式的峰值压力均为 15cmH2O，呼气末正压为 5cmH2O，呼吸频率为 20/min，吸入氧分数为 0.3。每 15 分钟收集一次所有呼吸变量。潮气量和呼吸分钟通气量在 FCV（=5）中显著低于 PCV（=5）动物[4.6 比 6.6，MD-2.0（95%CI-2.6 至-1.4）mL/kg；<0.001 和 7.3 比 9.5，MD-2.2（95%CI-3.3 至-1.0）L/min；=0.006]。尽管存在这些差异，但 FCV 的 CO 去除和氧合作用并不逊于 PCV。使用相同呼吸机设置进行机械通气时，FCV 的潮气量和随后的分钟通气量低于 PCV。这一发现可以通过 FCV 中的连续气流模式来解释，该模式需要较低的肺泡压力振幅。有趣的是，两组之间的气体交换相当，这表明在连续气流模式下通风效率得到了提高。本研究检查了连续（流量控制通气，FCV）与减速（压力控制通气，PCV）气流模式在机械通气中的影响。结果表明，FCV 需要较低的肺泡压力振幅，导致应用的潮气量和随后的分钟通气量减少。尽管存在这些差异，但 FCV 的 CO 去除和氧合作用并不逊于 PCV，这表明在连续气流模式下气体交换效率得到了提高。
