Wittenstein Jakob, Scharffenberg Martin, Ran Xi, Keller Diana, Michler Pia, Tauer Sebastian, Theilen Raphael, Kiss Thomas, Bluth Thomas, Koch Thea, Gama de Abreu Marcelo, Huhle Robert
Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
Intensive Care Med Exp. 2020 Dec 18;8(Suppl 1):24. doi: 10.1186/s40635-020-00308-0.
Flow-controlled ventilation (FCV) allows expiratory flow control, reducing the collapse of the airways during expiration. The performance of FCV during one-lung ventilation (OLV) under intravascular normo- and hypovolaemia is currently unknown. In this explorative study, we hypothesised that OLV with FCV improves PaO and reduces mechanical power compared to volume-controlled ventilation (VCV). Sixteen juvenile pigs were randomly assigned to one of two groups: (1) intravascular normovolaemia (n = 8) and (2) intravascular hypovolaemia (n = 8). To mimic inflammation due to major thoracic surgery, a thoracotomy was performed, and 0.5 μg/kg/h lipopolysaccharides from Escherichia coli continuously administered intravenously. Animals were randomly assigned to OLV with one of two sequences (60 min per mode): (1) VCV-FCV or (2) FCV-VCV. Variables of gas exchange, haemodynamics and respiratory signals were collected 20, 40 and 60 min after initiation of OLV with each mechanical ventilation mode. The distribution of ventilation was determined using electrical impedance tomography (EIT).
Oxygenation did not differ significantly between modes (P = 0.881). In the normovolaemia group, the corrected expired minute volume (P = 0.022) and positive end-expiratory pressure (PEEP) were lower during FCV than VCV. The minute volume (P ≤ 0.001), respiratory rate (P ≤ 0.001), total PEEP (P ≤ 0.001), resistance of the respiratory system (P ≤ 0.001), mechanical power (P ≤ 0.001) and resistive mechanical power (P ≤ 0.001) were lower during FCV than VCV irrespective of the volaemia status. The distribution of ventilation did not differ between both ventilation modes (P = 0.103).
In a model of OLV in normo- and hypovolemic pigs, mechanical power was lower during FCV compared to VCV, without significant differences in oxygenation. Furthermore, the efficacy of ventilation was higher during FCV compared to VCV during normovolaemia.
流量控制通气（FCV）可实现呼气流量控制，减少呼气过程中气道的塌陷。目前尚不清楚在血管内容量正常和低血容量状态下，单肺通气（OLV）期间FCV的性能。在这项探索性研究中，我们假设与容量控制通气（VCV）相比，FCV用于OLV可改善动脉血氧分压（PaO）并降低机械功率。16只幼年猪被随机分为两组之一：（1）血管内容量正常组（n = 8）和（2）血管内容量低血容量组（n = 8）。为模拟重大胸科手术引起的炎症，进行开胸手术，并以0.5μg/kg/h的剂量持续静脉输注来自大肠杆菌的脂多糖。动物被随机分配接受两种通气模式之一的OLV（每种模式60分钟）：（1）VCV-FCV或（2）FCV-VCV。在每种机械通气模式开始OLV后20、40和60分钟收集气体交换、血流动力学和呼吸信号变量。使用电阻抗断层扫描（EIT）确定通气分布。
两种模式之间的氧合无显著差异（P = 0.881）。在容量正常组中，FCV期间的校正呼出分钟通气量（P = 0.022）和呼气末正压（PEEP）低于VCV。无论容量状态如何，FCV期间的分钟通气量（P≤0.001）、呼吸频率（P≤0.001）、总PEEP（P≤0.001）、呼吸系统阻力（P≤0.001）、机械功率（P≤0.001）和阻力机械功率（P≤0.001）均低于VCV。两种通气模式之间的通气分布无差异（P = 0.103）。
在容量正常和低血容量猪的OLV模型中，与VCV相比，FCV期间的机械功率较低，氧合无显著差异。此外，在容量正常期间，FCV期间的通气效率高于VCV。
