Forces involved in lobar atelectasis in intact dogs

1980 ◽  
Vol 48 (1) ◽  
pp. 29-33 ◽  
Author(s):  
G. T. Ford ◽  
C. A. Bradley ◽  
N. R. Anthonisen
Keyword(s):  
Chest Wall ◽  
Lower Lobe ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Lateral Position ◽  
Relative Volume ◽  
Left Lower Lobe ◽  
Lung Lobe ◽  
Left Lateral Position ◽  
The Difference

When an excised lung lobe undergoes atelectasis, its shape differs from that observed when lobar atelectasis occurs in an intact animal: the chest wall deforms the collapsing lobe. In eight anesthetized dogs in the left lateral position we measured lung volume and transpulmonary pressure during the development of atelectasis. We then induced atelectasis of the left lower lobe with the rest of the lung maintained at FRC and measured lobar volume and "translobar" (lobar minus esophageal) pressure. Lung and lobar volumes were measured by prebreathing the animal with 88% O2-12% N2, occluding the airway and observing the increase in lung or lobar N2 concentration. When the left lower lobe alone collapsed, translobar pressures were more negative than transpulmonary pressure at the same relative volume when the whole lung collapsed. This pressure difference, which represents the deforming force applied to the lobe minus the pressure costs of deformation, averaged 3 cmH2O at 50% FRC. Infusion of 25 ml of normal saline into the pleural space sharply reduced the difference pulmonary pressure during lung collapse: this difference was abolished at 80% FRC and halved at 50% FRC. The large effect of the small volume of fluid suggested that deforming forces were largely generated in relatively local areas, such as regions of the chest wall with sharp angulation.

Respiratory mechanics in the anesthetized rat

1978 ◽  
Vol 45 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Y. L. Lai ◽  
J. Hildebrandt
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Esophageal Pressure ◽  
Gas Content ◽  
Lung Capacity ◽  
Consistent Change ◽  
Residual Capacity ◽  
Wall Compliance ◽  
The Difference ◽  
Body Plethysmograph

Functional residual capacity (FRC) and pressure-volume (PV) curves of the lung, chest wall, and total respiratory system were studied in 15 anesthetized rats, weighing 307 +/- 10 (SE) g. Pleural pressure was estimated from the esophageal pressure measured with a water-filled catheter. The FRC determined by body plethysmograph was slightly and significantly larger than FRC determined from saline displacement of excised lungs. The difference may be accounted for by O2 uptake by lung tissue, escape of CO2 through the pleura, and abdominal gas. Paralysis in the prone position did not affect FRC, and abdominal gas content contributed only slightly to the FRC measured by body plethysmograph. Values of various pulmonary parameters (mean +/- SE) were as follows: residual volume, 1.26 +/- 0.13 ml; FRC, 2.51 +/- 0.20 ml; total lung capacity, 12.23 +/- 0.55 ml; compliance of the lung, 0.90 +/- 0.06 ml/cmH2O; chest wall compliance, 1.50 +/- 0.11 ml/cmH2O; and respiratory system compliance, 0.57 +/- 0.03 ml/cmH2O. The lung PV curve did not show a consistent change after the chest was opened.

Effect of the chest wall and blood volume on pulmonary distensibility

1992 ◽  
Vol 72 (1) ◽  
pp. 186-193 ◽  
Author(s):  
H. J. Colebatch ◽  
C. K. Ng ◽  
N. Berend ◽  
F. J. Maccioni
Keyword(s):  
Chest Wall ◽  
Blood Volume ◽  
Surface Pressure ◽  
Supine Position ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Relative Increase ◽  
Alveolar Volume ◽  
Pulmonary Blood Volume ◽  
Gas Volume

To determine the reason for increased pulmonary distensibility in excised lungs, we performed deflation pressure-volume (PV) studies in 24 dogs. Exponential analysis of PV data gave K, an index of distensibility. Lung volume was measured by dilution of neon. Compared with measurements obtained in the supine position, with the chest closed, and with esophageal pressure (Pes) to obtain transpulmonary pressure, K was not changed significantly with the chest strapped, with pleural pressure to obtain transpulmonary pressure, or with the chest open. From displacement of PV curves obtained in the supine position and with the chest closed or open, we estimated that Pes was 0.18 kPa greater than average lung surface pressure. An increase in K in the prone and head-up positions was attributed to a traction artifact decreasing Pes. Exsanguination increased K and produced a relative increase in gas volume. These results show that overall pulmonary distensibility is unaffected by an intact chest wall. An increase in K and gas volume after exsanguination probably reflects a decreased pulmonary blood volume, with collapse of capillaries increasing the alveolar volume-to-surface ratio.

scholarly journals Determinants of the esophageal-pleural pressure relationship in humans

2020 ◽  
Vol 128 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Iacopo Pasticci ◽  
Paolo Cadringher ◽  
Lorenzo Giosa ◽  
Michele Umbrello ◽  
Paolo Formenti ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Chest Wall ◽  
Supine Position ◽  
Body Position ◽  
Esophageal Pressure ◽  
Lateral Position ◽  
Pleural Pressure ◽  
Absolute Value ◽  
Gravitational Forces ◽  
Chest Wall Elastance

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 cmH2O. In the supine position, the difference amounted to 7.3 ± 2.8 cmH2O. In the supine position, the estimated compressive forces on the mediastinum were 10.5 ± 3.1 cmH2O and on the iso-gravitational pleural plane 3.2 ± 1.8 cmH2O. 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 ( r2 = 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 (Ecw) measured by intrathoracic (Ecw = ΔPpl/tidal volume) or esophageal pressure (Ecw = 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. NEW & NOTEWORTHY 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.

scholarly journals Lung Injury after In Vivo  Reperfusion

2008 ◽  
Vol 109 (2) ◽  
pp. 269-278 ◽  
Author(s):  
Idit Matot ◽  
Sharon Einav ◽  
Carolyn F. Weiniger ◽  
Ron G. Pearl ◽  
Rinat Abramovitch ◽  
...  
Keyword(s):  
Lung Injury ◽  
Lower Lobe ◽  
Receptor Activation ◽  
Left Lower Lobe ◽  
Lung Edema ◽  
Lung Lobe ◽  
Time Period ◽  
Adenosine Receptor Agonist ◽  
A3 Adenosine Receptor

Background Although short-term findings after lung reperfusion have been extensively reported, in vivo animal studies have not described outcome beyond the immediate time period. Therefore, the authors evaluated lung injury 27 h after reperfusion. They also investigated whether attenuation of lung injury with the A3 adenosine receptor agonist MRS3558 was sustained beyond the immediate time period. Methods In intact-chest, spontaneously breathing cats in which the left lower lung lobe was isolated and subjected to 2 h of ischemia and 3 h of reperfusion, MRS3558 was administered before reperfusion. Animals were killed 3 or 27 h after reperfusion. Results When compared with 3 h of reperfusion, at 27 h the left lower lobe showed reduced apoptosis and no change in inflammation, but increased edema. Increased edema of the nonischemic right lung and hypoxemia were observed at 27 h after left lower lobe reperfusion. Increases in phosphorylated p38 levels were found at 3 h of reperfusion compared with control lung, with further increases at 27 h. The attenuation of injury observed with MRS3558 treatment at 3 h of reperfusion was sustained at 27 h. Conclusions Lung edema may worsen hours after the immediate postreperfusion period, even though lung apoptosis and inflammation are reduced or show no change, respectively. This was associated with further increases in phosphorylated p38 levels. The nonischemic lung may also be affected, suggesting a systemic response to reperfusion. In addition, early attenuation of injury is beneficial beyond the immediate period after reperfusion. Treatment aimed at inhibiting p38 activation, such as A3 receptor activation, should be further studied to explore its potential long-term beneficial effect.

Case 13.5

2014 ◽  
pp. 623-624
Author(s):  
Christine U. Lee ◽  
James F. Glockner
Keyword(s):  
Soft Tissue ◽  
Chest Wall ◽  
Chest Radiograph ◽  
Lower Lobe ◽  
Left Lower Lobe ◽  
Minimal Extension ◽  
Nonproductive Cough ◽  
T2 Weighted Images

72-year-old woman with a nonproductive cough and a mass on chest radiograph Axial (Figure 13.5.1) and sagittal (Figure 13.5.2) fat-suppressed FSE T2-weighted images reveal a large centrally necrotic mass in the posterior left lower lobe. Notice the subtle tail of soft tissue extending across the pleura with minimal extension into the chest wall. Axial postgadolinium 3D SPGR images (...

Effect of alveolar and pleural pressures on interstitial pressures in isolated dog lungs

1991 ◽  
Vol 70 (2) ◽  
pp. 914-918 ◽  
Author(s):  
M. R. Glucksberg ◽  
J. Bhattacharya
Keyword(s):  
Transpulmonary Pressure ◽  
Pleural Pressure ◽  
Alveolar Pressure ◽  
Lung Lobe ◽  
Direct Measurements ◽  
The Difference

We report the first direct measurements of perialveolar interstitial pressures in lungs inflated with negative pleural pressure. In eight experiments, we varied surrounding (pleural) pressure in a dog lung lobe to maintain constant inflation with either positive alveolar and ambient atmospheric pleural pressures (positive inflation) or ambient atmospheric alveolar and negative pleural pressures (negative inflation). Throughout, vascular pressure was approximately 4 cmH2O above pleural pressure. By the micropuncture servo-null technique we recorded interstitial pressures at alveolar junctions (Pjct) and in the perimicrovascular adventitia (Padv). At transpulmonary pressure of 7 cmH2O (n = 4), the difference of Pjct and Pady from pleural pressure of 0.9 +/- 0.4 and -1.1 +/- 0.2 cmH2O, respectively, during positive inflation did not significantly change (P less than 0.05) after negative inflation. After increase of transpulmonary pressure from 7 to 15 cmH2O (n = 4), the decrease of Pjct by 3.3 +/- 0.3 cmH2O and Pady by 2.0 +/- 0.4 cmH2O during positive inflation did not change during negative inflation. The Pjct-Pady gradient was not affected by the mode of inflation. Our measurements indicate that, in lung, when all pressures are referred to pleural or alveolar pressure, the mode of inflation does not affect perialveolar interstitial pressures.

Effects of Prone Positioning on Transpulmonary Pressures and End-expiratory Volumes in Patients without Lung Disease

2018 ◽  
Vol 128 (6) ◽  
pp. 1187-1192 ◽  
Author(s):  
Abirami Kumaresan ◽  
Robert Gerber ◽  
Ariel Mueller ◽  
Stephen H. Loring ◽  
Daniel Talmor
Keyword(s):  
Chest Wall ◽  
Prone Position ◽  
Airway Pressure ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Driving Pressure ◽  
Prone Positioning ◽  
Volume Increase ◽  
Mechanically Ventilated ◽  
Chest Wall Elastance

Abstract Background The effects of prone positioning on esophageal pressures have not been investigated in mechanically ventilated patients. Our objective was to characterize effects of prone positioning on esophageal pressures, transpulmonary pressure, and lung volume, thereby assessing the potential utility of esophageal pressure measurements in setting positive end-expiratory pressure (PEEP) in prone patients. Methods We studied 16 patients undergoing spine surgery during general anesthesia and neuromuscular blockade. We measured airway pressure, esophageal pressures, airflow, and volume, and calculated the expiratory reserve volume and the elastances of the lung and chest wall in supine and prone positions. Results Esophageal pressures at end expiration with 0 cm H2O PEEP decreased from supine to prone by 5.64 cm H2O (95% CI, 3.37 to 7.90; P < 0.0001). Expiratory reserve volume measured at relaxation volume increased from supine to prone by 0.15 l (interquartile range, 0.25, 0.10; P = 0.003). Chest wall elastance increased from supine to prone by 7.32 (95% CI, 4.77 to 9.87) cm H2O/l at PEEP 0 (P < 0.0001) and 6.66 cm H2O/l (95% CI, 3.91 to 9.41) at PEEP 7 (P = 0.0002). Median driving pressure, the change in airway pressure from end expiration to end-inspiratory plateau, increased in the prone position at PEEP 0 (3.70 cm H2O; 95% CI, 1.74 to 5.66; P = 0.001) and PEEP 7 (3.90 cm H2O; 95% CI, 2.72 to 5.09; P < 0.0001). Conclusions End-expiratory esophageal pressure decreases, and end-expiratory transpulmonary pressure and expiratory reserve volume increase, when patients are moved from supine to prone position. Mean respiratory system driving pressure increases in the prone position due to increased chest wall elastance. The increase in end-expiratory transpulmonary pressure and expiratory reserve volume may be one mechanism for the observed clinical benefit with prone positioning.

Effects of acute pleural effusion on respiratory system mechanics in dogs

1985 ◽  
Vol 59 (5) ◽  
pp. 1458-1463 ◽  
Author(s):  
W. S. Krell ◽  
J. R. Rodarte
Keyword(s):  
Chest Wall ◽  
Shape Change ◽  
Lower Lobe ◽  
Esophageal Pressure ◽  
Elastic Recoil ◽  
Cross Sectional ◽  
Before And After ◽  
Residual Capacity ◽  
Upward Displacement ◽  
The Right

We determined regional (Vr) and overall lung volumes in six head-up anesthetized dogs before and after the stepwise introduction of saline into the right pleural space. Functional residual capacity (FRC), as determined by He dilution, and total lung capacity (TLC) decreased by one-third and chest wall volume increased by two-thirds the saline volume added. Pressure-volume curves showed an apparent increase in lung elastic recoil and a decrease in chest wall elastic recoil with added saline, but the validity of esophageal pressure measurements in these head-up dogs is questionable. Vr was determined from the positions of intraparenchymal markers. Lower lobe TLC and FRC decreased with added saline. The decrease in upper lobe volume was less than that of lower lobe volume at FRC and was minimal at TLC. Saline increased the normal Vr gradient at FRC and created a gradient at TLC. During deflation from TLC to FRC before saline was added, the decrease in lung volume was accompanied by a shape change of the lung, with greatest distortion in the transverse (ribs to mediastinum) direction. After saline additions, deflation was associated with deformation of the lung in the cephalocaudal and transverse directions. The deformation with saline may be a result of upward displacement of the lungs into a smaller cross-sectional area of the thoracic cavity.

Lower lobe origin is related to unfavorable outcomes in patients with stage I–III lung cancer treated with radical chemoradiotherapy

2020 ◽  
pp. 030089162097135
Author(s):  
Fangfang Liu ◽  
Xun Yuan ◽  
Jizong Jiang ◽  
Peng Zhang ◽  
Yuan Chen ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Lung Tumor ◽  
Survival Rates ◽  
Lower Lobe ◽  
Tumor Location ◽  
Stage I ◽  
Lung Lobe ◽  
Tumor Origin ◽  
Lower Lung ◽  
The Difference

Purpose: The influence of tumor location on survival was investigated in patients with lung cancer who received radical chemoradiotherapy. Methods: We examined the relationships between radiation site and survival outcome in patients with lung cancer. A total of 14,640 patients with lung cancer who received radical chemoradiotherapy for stage I–III disease were reviewed from Surveillance, Epidemiology, and End Results Program (SEER) datasets. We further retrospectively collected cases from a cohort of 148 eligible patients diagnosed between December 2013 and December 2019. Results: Female sex, adenocarcinoma, and stage III disease were significantly correlated with right lung lobe tumor. Advanced age at diagnosis was associated with lower lung tumor origin. For the patients who received radical chemoradiotherapy, 1- and 3-year survival rates were 56.5% and 22.9%. Lower lobe origin was closely related to a shorter overall survival compared to non-right lower lobe tumors ( p < 0.001). We also validated the difference in our cohort ( p = 0.004). Conclusions: Our results suggest that lower lobe tumor increases mortality risk in patients with lung cancer treated with radical chemoradiotherapy.

scholarly journals Goal-Directed Mechanical Ventilation: Are We Aiming at the Right Goals? A Proposal for an Alternative Approach Aiming at Optimal Lung Compliance, Guided by Esophageal Pressure in Acute Respiratory Failure

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Arie Soroksky ◽  
Antonio Esquinas
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory Failure ◽  
Acute Respiratory Failure ◽  
Chest Wall ◽  
Respiratory System ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Plateau Pressure ◽  
Lung Compliance ◽  
Inspiratory Pressure

Patients with acute respiratory failure and decreased respiratory system compliance due to ARDS frequently present a formidable challenge. These patients are often subjected to high inspiratory pressure, and in severe cases in order to improve oxygenation and preserve life, we may need to resort to unconventional measures. The currently accepted ARDSNet guidelines are characterized by a generalized approach in which an algorithm for PEEP application and limited plateau pressure are applied to all mechanically ventilated patients. These guidelines do not make any distinction between patients, who may have different chest wall mechanics with diverse pathologies and different mechanical properties of their respiratory system. The ability of assessing pleural pressure by measuring esophageal pressure allows us to partition the respiratory system into its main components of lungs and chest wall. Thus, identifying the dominant factor affecting respiratory system may better direct and optimize mechanical ventilation. Instead of limiting inspiratory pressure by plateau pressure, PEEP and inspiratory pressure adjustment would be individualized specifically for each patient's lung compliance as indicated by transpulmonary pressure. The main goal of this approach is to specifically target transpulmonary pressure instead of plateau pressure, and therefore achieve the best lung compliance with the least transpulmonary pressure possible.

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