Prella Maura, Feihl François, Domenighetti Guido
Multidisciplinary ICU, Regional Hospital La Carità, 6600 Locarno, Switzerland.
Chest. 2002 Oct;122(4):1382-8. doi: 10.1378/chest.122.4.1382.
The potential clinical benefits of pressure-controlled ventilation (PCV) over volume-controlled ventilation (VCV) in patients with acute lung injury (ALI) or ARDS still remain debated. We compared PCV with VCV in patients with ALI/ARDS with respect to the following physiologic end points: (1) gas exchange and airway pressures, and (2) CT scan intrapulmonary gas distribution at end-expiration.
Prospective, observational study.
A multidisciplinary ICU in a nonuniversity, acute-care hospital.
Ten patients with ALI or ARDS (9 men and 1 woman; age range, 17 to 80 years).
Sequential ventilation in PCV and VCV with a constant inspiratory/expiratory ratio, tidal volume, respiratory rate, and total positive end-expiratory pressure; measurement of gas exchange and airway pressures; and achievement of CT sections at lung base, hilum, and apex for the quantitative analysis of lung densities and of aerated vs nonaerated zones.
PaO(2), PaCO(2), and PaO(2)/fraction of inspired oxygen ratio levels did not differ between PCV and VCV. Peak airway pressure (Ppeak) was significantly lower in PCV compared with VCV (26 +/- 2 cm H(2)O vs 31 +/- 2 cm H(2)O; p < 0.001; mean +/- SEM). The surface areas of the nonaerated zones as well as the total areas at each section level were unchanged in PCV compared with VCV, except at the apex level, where there was a significantly greater nonaerated area in VCV (11 +/- 2 cm(2) vs 9 +/- 2 cm(2); p < 0.05). The total mean CT number of each lung (20 lungs from 10 patients) was similar in the two modes, as were the density values at the basal and apical levels; the hilum mean CT number was - 442 +/- 28 Hounsfield units (HU) in VCV and - 430 +/- 26 HU in PCV (p < 0.005).
These data show that PCV allows the generation of lower Ppeaks through the precise titration of the lung distending pressure, and might be applied to avoid regional overdistension by means of a more homogeneous gas distribution.
在急性肺损伤（ALI）或急性呼吸窘迫综合征（ARDS）患者中，压力控制通气（PCV）相较于容量控制通气（VCV）的潜在临床益处仍存在争议。我们在ALI/ARDS患者中比较了PCV和VCV在以下生理终点方面的差异：（1）气体交换和气道压力，以及（2）呼气末CT扫描肺内气体分布。
前瞻性观察性研究。
一家非大学的急症医院的多学科重症监护病房。
10例ALI或ARDS患者（9例男性，1例女性；年龄范围17至80岁）。
以恒定的吸呼比、潮气量、呼吸频率和呼气末正压进行PCV和VCV的序贯通气；测量气体交换和气道压力；获取肺底部、肺门和肺尖的CT图像，用于定量分析肺密度以及充气区与未充气区。
PCV和VCV之间的PaO₂、PaCO₂以及PaO₂/吸入氧分数比值水平无差异。与VCV相比，PCV的气道峰压（Ppeak）显著更低（26±2 cmH₂O对31±2 cmH₂O；p<0.001；均值±标准误）。与VCV相比，PCV时各层面未充气区的表面积以及总面积均无变化，但在肺尖层面，VCV的未充气面积显著更大（11±2 cm²对9±2 cm²；p<0.05）。两种通气模式下，每个肺（来自10例患者的20个肺）的总平均CT值相似，肺底部和肺尖层面的密度值也相似；肺门平均CT值在VCV时为-442±28亨氏单位（HU），在PCV时为-430±26 HU（p<0.005）。
这些数据表明，PCV通过精确滴定肺扩张压力可产生更低的Ppeak，并且可能通过更均匀的气体分布来避免局部过度扩张。
