Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany.
Dipartimento Anestesia, Rianimazione ed Emergenza-Urgenza, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
J Appl Physiol (1985). 2020 Jan 1;128(1):78-86. doi: 10.1152/japplphysiol.00587.2019. Epub 2019 Nov 27.
Esophageal pressure has been suggested as adequate surrogate of the pleural pressure. We investigate after lung surgery the determinants of the esophageal and intrathoracic pressures and their differences. The esophageal pressure (through esophageal balloon) and the intrathoracic/pleural pressure (through the chest tube on the surgery side) were measured after surgery in 28 patients immediately after lobectomy or wedge resection. Measurements were made in the nondependent lateral position (without or with ventilation of the operated lung) and in the supine position. In the lateral position with the nondependent lung, collapsed or ventilated, the differences between esophageal and pleural pressure amounted to 4.4 ± 1.6 and 5.1 ± 1.7 cmHO. In the supine position, the difference amounted to 7.3 ± 2.8 cmHO. In the supine position, the estimated compressive forces on the mediastinum were 10.5 ± 3.1 cmHO and on the iso-gravitational pleural plane 3.2 ± 1.8 cmHO. A simple model describing the roles of chest, lung, and pneumothorax volume matching on the pleural pressure genesis was developed; modeled pleural pressure = 1.0057 × measured pleural pressure + 0.6592 ( = 0.8). Whatever the position and the ventilator settings, the esophageal pressure changed in a 1:1 ratio with the changes in pleural pressure. Consequently, chest wall elastance (E) measured by intrathoracic (E = ΔPpl/tidal volume) or esophageal pressure (E = ΔPes/tidal volume) was identical in all the positions we tested. We conclude that esophageal and pleural pressures may be largely different depending on body position (gravitational forces) and lung-chest wall volume matching. Their changes, however, are identical. Esophageal and pleural pressure changes occur at a 1:1 ratio, fully justifying the use of esophageal pressure to compute the chest wall elastance and the changes in pleural pressure and in lung stress. The absolute value of esophageal and pleural pressures may be largely different, depending on the body position (gravitational forces) and the lung-chest wall volume matching. Therefore, the absolute value of esophageal pressure should not be used as a surrogate of pleural pressure.
食管压力已被建议作为胸腔压力的合适替代指标。我们研究了肺手术后食管压和胸腔内压及其差值的决定因素。在 28 例肺叶切除术或楔形切除术患者中，在手术后立即测量了术后胸腔管（手术侧）的食管压（通过食管球囊）和胸腔内/胸腔压。测量在非依赖侧卧位（不使用或使用患肺通气）和仰卧位进行。在非依赖侧卧位，塌陷或通气的肺，食管压和胸腔压之间的差异为 4.4 ± 1.6 和 5.1 ± 1.7 cmH2O。仰卧位时，差值为 7.3 ± 2.8 cmH2O。仰卧位时，对纵隔的估计压缩力为 10.5 ± 3.1 cmH2O，对等重力性胸膜平面的压缩力为 3.2 ± 1.8 cmH2O。开发了一个简单的模型来描述胸廓、肺和气胸容积匹配对胸腔压发生的作用；模拟胸腔压=1.0057×测量胸腔压+0.6592（=0.8）。无论位置和呼吸机设置如何，食管压的变化与胸腔压的变化呈 1:1 比例。因此，通过胸腔内压（E=ΔPpl/潮气量）或食管压（E=ΔPes/潮气量）测量的胸壁弹性（E）在我们测试的所有位置都相同。我们得出结论，食管压和胸腔压可能因体位（重力）和肺-胸壁容积匹配的不同而有很大差异。然而，它们的变化是相同的。食管压和胸腔压的变化呈 1:1 比例，完全证明了使用食管压来计算胸壁弹性和胸腔压及肺应力的变化是合理的。食管压和胸腔压的绝对值可能因体位（重力）和肺-胸壁容积匹配的不同而有很大差异。因此，食管压的绝对值不应作为胸腔压的替代指标。
