Pairwise Registration Enhances Analysis of Lung Inflation in Prone vs. Supine Pigs with Lung Injury

2019 ◽  
Author(s):  
Y. Xin ◽  
M. Cereda ◽  
N. Tustison ◽  
S. Na ◽  
H. Hamedani ◽  
...  
Keyword(s):  
Lung Injury ◽  
Lung Inflation ◽  
Pairwise Registration

Lung water measurement by nuclear magnetic resonance: correlation with morphometry

1995 ◽  
Vol 79 (6) ◽  
pp. 2163-2168 ◽  
Author(s):  
A. G. Cutillo ◽  
K. C. Goodrich ◽  
K. Ganesan ◽  
S. Watanabe ◽  
D. C. Ailion ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Oleic Acid ◽  
Magnetic Resonance ◽  
Lung Injury ◽  
Water Density ◽  
Inflation Pressure ◽  
Lung Water ◽  
Lung Inflation ◽  
Lung Water Content

Estimates of lung water content obtained from nuclear magnetic resonance (NMR) and morphometric and gravimetric measurements were compared in normal and experimentally injured rats. Average lung water density (rho H2O) was measured by an NMR technique in excised unperfused rat lungs (20 normal lungs and 12 lungs with oleic acid-induced edema) at 0 (full passive deflation) and 30 cmH2O lung inflation pressure and in vivo (4 normal rats and 8 rats with lung injury induced by oleic acid or rapid saline infusion). The rho H2O values were compared with morphometric measurements of lung tissue volume density (Vv) obtained from the same lungs fixed at corresponding liquid-instillation pressures. A close correlation was observed between rho H2O and Vv in normal and injured excised lungs [correlation coefficient (r) = 0.910, P < 0.01]. In vivo rho H2O was also closely correlated with Vv (r = 0.897, P < 0.01). The correlation coefficients between rho H2O and gravimetric lung water content (LWGr) were lower in the excised lung group (r = 0.663 and 0.692, respectively, for rho H2O at 0 and 30 cmH2O lung inflation pressure, P < 0.01) than in the in vivo study (r = 0.857, P < 0.01). Our results indicate that NMR techniques, which are noninvasive and nondestructive, provide reliable estimates of lung water density and that the influence of lung inflation on rho H2O is important (compared with the effect of lung water accumulation in lung injury) only in the presence of deliberately induced very large variations in the lung inflation level.

Acute Lung Injury: Effects of Prone Positioning on Cephalocaudal Distribution of Lung Inflation—CT Assessment in Dogs

Radiology ◽  
2005 ◽  
Vol 234 (1) ◽  
pp. 151-161 ◽  
Author(s):  
Hyun Ju Lee ◽  
Jung-Gi Im ◽  
Jin Mo Goo ◽  
Young Il Kim ◽  
Min Woo Lee ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Prone Positioning ◽  
Lung Inflation

Comparison of three tracers for detecting lung epithelial injury in anesthetized sheep

1989 ◽  
Vol 66 (5) ◽  
pp. 2374-2383 ◽  
Author(s):  
B. T. Peterson ◽  
K. D. Dickerson ◽  
H. L. James ◽  
E. J. Miller ◽  
J. W. McLarty ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Lung Injury ◽  
Clearance Rate ◽  
Fluid Transport ◽  
Water Volume ◽  
Lung Edema ◽  
Lung Water ◽  
Lung Inflation ◽  
Epithelial Injury ◽  
Lung Epithelial

We compared the ability of three aerosolized tracers to discriminate among control, lung inflation with a positive end expired pressure of 10 cmH2O, lung vascular hypertension and edema without lung injury, and lung edema with lung injury due to intravenous oleic acid. The tracers were 99mTc-diethylenetriaminepentaacetate (99mTc-DTPA, mol wt 492), 99mTc-human serum albumin (99mTc-ALB, mol wt 69,000), and 99mTc-aggregated albumin (99mTc-AGG ALB, mol wt 383,000). 99mTc-DTPA clearance measurements were not able to discriminate lung injury from lung inflation. The 99mTc-AGG ALB clearance rate was unchanged by lung inflation and increased slightly with lung injury. The 99mTc-ALB clearance rate (0.06 +/- 0.02%/min) was unchanged by lung inflation (0.09 +/- 0.02%/min, P greater than 0.05) or 4 h of hypertension without injury (0.09 +/- 0.04%/min, P greater than 0.05). Deposition of 99mTc-ALB within 15 min of the administration of the oleic acid increased the clearance rate to 0.19 +/- 0.06%/min, which correlated well with the postmortem lung water volume (r = 0.92, P less than 0.01). This did not occur when there was a 60-min delay in the deposition of 99mTc-ALB. We conclude that 99mTc-ALB is the best indicator for studying the effects of lung epithelial injury on protein and fluid transport into and out of the air spaces of the lungs in a minimally invasive manner.

Mechanism by Which a Sustained Inflation Can Worsen Oxygenation in Acute Lung Injury

2004 ◽  
Vol 100 (2) ◽  
pp. 323-330 ◽  
Author(s):  
Guido Musch ◽  
R. Scott Harris ◽  
Marcos F. Vidal Melo ◽  
Kevin R. O’Neill ◽  
J. Dominick H. Layfield ◽  
...  
Keyword(s):  
Blood Flow ◽  
Acute Lung Injury ◽  
Gas Exchange ◽  
Lung Injury ◽  
Pulmonary Blood Flow ◽  
Lung Inflation ◽  
Positron Emission ◽  
Regional Lung Function ◽  
Sustained Inflation ◽  
Physiologic Data

Background Sustained lung inflations (recruitment maneuvers [RMs]) are occasionally used during mechanical ventilation of patients with acute lung injury to restore aeration to atelectatic alveoli. However, RMs do not improve, and may even worsen, gas exchange in a fraction of these patients. In this study, the authors sought to determine the mechanism by which an RM can impair gas exchange in acute lung injury. Methods The authors selected a model of acute lung injury that was unlikely to exhibit sustained recruitment in response to a lung inflation. In five sheep, lung injury was induced by lavage with 0.2% polysorbate 80 in saline. Positron emission tomography and [13N]nitrogen were used to assess regional lung function in dependent, middle, and nondependent lung regions. Physiologic data and positron emission scans were collected before and 5 min after a sustained inflation (continuous positive airway pressure of 50 cm H2O for 30 s). Results All animals showed greater loss of aeration and higher perfusion and shunting blood flow in the dependent region. After the RM, Pao2 decreased in all animals by 35 +/- 22 mmHg (P &lt; 0.05). This decrease in Pao2 was associated with redistribution of pulmonary blood flow from the middle, more aerated region to the dependent, less aerated region (P &lt; 0.05) and with an increase in the fraction of pulmonary blood flow that was shunted in the dependent region (P &lt; 0.05). Neither respiratory compliance nor aeration of the dependent region improved after the RM. Conclusions When a sustained inflation does not restore aeration to atelectatic regions, it can worsen oxygenation by increasing the fraction of pulmonary blood flow that is shunted in nonaerated regions.

scholarly journals Positional Therapy and Regional Pulmonary Ventilation

2020 ◽  
Vol 133 (5) ◽  
pp. 1093-1105
Author(s):  
Yi Xin ◽  
Maurizio Cereda ◽  
Hooman Hamedani ◽  
Kevin T. Martin ◽  
Nicholas J. Tustison ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Lung Injury ◽  
Body Position ◽  
Pulmonary Ventilation ◽  
Large Animal ◽  
Prone Positioning ◽  
Lung Mass ◽  
Lung Inflation ◽  
Regional Cluster ◽  
Before And After

Background Prone ventilation redistributes lung inflation along the gravitational axis; however, localized, nongravitational effects of body position are less well characterized. The authors hypothesize that positional inflation improvements follow both gravitational and nongravitational distributions. This study is a nonoverlapping reanalysis of previously published large animal data. Methods Five intubated, mechanically ventilated pigs were imaged before and after lung injury by tracheal injection of hydrochloric acid (2 ml/kg). Computed tomography scans were performed at 5 and 10 cm H2O positive end-expiratory pressure (PEEP) in both prone and supine positions. All paired prone–supine images were digitally aligned to each other. Each unit of lung tissue was assigned to three clusters (K-means) according to positional changes of its density and dimensions. The regional cluster distribution was analyzed. Units of tissue displaying lung recruitment were mapped. Results We characterized three tissue clusters on computed tomography: deflation (increased tissue density and contraction), limited response (stable density and volume), and reinflation (decreased density and expansion). The respective clusters occupied (mean ± SD including all studied conditions) 29.3 ± 12.9%, 47.6 ± 11.4%, and 23.1 ± 8.3% of total lung mass, with similar distributions before and after lung injury. Reinflation was slightly greater at higher PEEP after injury. Larger proportions of the reinflation cluster were contained in the dorsal versus ventral (86.4 ± 8.5% vs. 13.6 ± 8.5%, P &lt; 0.001) and in the caudal versus cranial (63.4 ± 11.2% vs. 36.6 ± 11.2%, P &lt; 0.001) regions of the lung. After injury, prone positioning recruited 64.5 ± 36.7 g of tissue (11.4 ± 6.7% of total lung mass) at lower PEEP, and 49.9 ± 12.9 g (8.9 ± 2.8% of total mass) at higher PEEP; more than 59.0% of this recruitment was caudal. Conclusions During mechanical ventilation, lung reinflation and recruitment by the prone positioning were primarily localized in the dorso-caudal lung. The local effects of positioning in this lung region may determine its clinical efficacy. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

scholarly journals Magnetic resonance behavior of normal and diseased lungs: spherical shell model simulations

2000 ◽  
Vol 88 (4) ◽  
pp. 1155-1166 ◽  
Author(s):  
Carl H. Durney ◽  
Antonio G. Cutillo ◽  
David C. Ailion
Keyword(s):  
Lung Injury ◽  
Spin Echo ◽  
Theoretical Data ◽  
Alveolar Recruitment ◽  
Spherical Shells ◽  
Lung Inflation ◽  
Resonance Behavior ◽  
Tissue Interface ◽  
The Difference ◽  
Asymmetric Spin Echo

The alveolar air-tissue interface affects the lung NMR signal, because it results in a susceptibility-induced magnetic field inhomogeneity. The air-tissue interface effect can be detected and quantified by measuring the difference signal (Δ) from a pair of NMR images obtained using temporally symmetric and asymmetric spin-echo sequences. The present study describes a multicompartment alveolar model (consisting of a collection of noninteracting spherical water shells) that simulates the behavior of Δ as a function of the level of lung inflation and can be used to predict the NMR response to various types of lung injury. The model was used to predict Δ as a function of the inflation level (with the assumption of sequential alveolar recruitment, partly parallel to distension) and to simulate pulmonary edema by deriving equations that describe Δ for a collection of spherical shells representing combinations of collapsed, flooded, and inflated alveoli. Our theoretical data were compared with those provided by other models and with experimental data obtained from the literature. Our results suggest that NMR Δ measurements can be used to study the mechanisms underlying the lung pressure-volume behavior, to characterize lung injury, and to assess the contributions of alveolar recruitment and distension to the lung volume changes in response to the application of positive airway pressure (e.g., positive end-expiratory pressure).

scholarly journals Esophageal pressures in acute lung injury: do they represent artifact or useful information about transpulmonary pressure, chest wall mechanics, and lung stress?

2010 ◽  
Vol 108 (3) ◽  
pp. 515-522 ◽  
Author(s):  
Stephen H. Loring ◽  
Carl R. O'Donnell ◽  
Negin Behazin ◽  
Atul Malhotra ◽  
Todd Sarge ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Critically Ill ◽  
Chest Wall ◽  
Critically Ill Patients ◽  
Transpulmonary Pressure ◽  
Pleural Pressure ◽  
Lung Inflation ◽  
Airway Pressures ◽  
Gravitational Gradients

Acute lung injury can be worsened by inappropriate mechanical ventilation, and numerous experimental studies suggest that ventilator-induced lung injury is increased by excessive lung inflation at end inspiration or inadequate lung inflation at end expiration. Lung inflation depends not only on airway pressures from the ventilator but, also, pleural pressure within the chest wall. Although esophageal pressure (Pes) measurements are often used to estimate pleural pressures in healthy subjects and patients, they are widely mistrusted and rarely used in critical illness. To assess the credibility of Pes as an estimate of pleural pressure in critically ill patients, we compared Pes measurements in 48 patients with acute lung injury with simultaneously measured gastric and bladder pressures (Pga and Pblad). End-expiratory Pes, Pga, and Pblad were high and varied widely among patients, averaging 18.6 ± 4.7, 18.4 ± 5.6, and 19.3 ± 7.8 cmH2O, respectively (mean ± SD). End-expiratory Pes was correlated with Pga ( P = 0.0004) and Pblad ( P = 0.0104) and unrelated to chest wall compliance. Pes-Pga differences were consistent with expected gravitational pressure gradients and transdiaphragmatic pressures. Transpulmonary pressure (airway pressure − Pes) was −2.8 ± 4.9 cmH2O at end exhalation and 8.3 ± 6.2 cmH2O at end inflation, values consistent with effects of mediastinal weight, gravitational gradients in pleural pressure, and airway closure at end exhalation. Lung parenchymal stress measured directly as end-inspiratory transpulmonary pressure was much less than stress inferred from the plateau airway pressures and lung and chest wall compliances. We suggest that Pes can be used to estimate transpulmonary pressures that are consistent with known physiology and can provide meaningful information, otherwise unavailable, in critically ill patients.

Pulmonary lymphatic clearance of 99mTc-DTPA from air spaces during lung inflation and lung injury

1987 ◽  
Vol 63 (3) ◽  
pp. 1136-1141 ◽  
Author(s):  
B. T. Peterson ◽  
L. D. Gray
Keyword(s):  
Blood Flow ◽  
Lung Injury ◽  
Control Group ◽  
Diethylenetriaminepentaacetic Acid ◽  
Lung Inflation ◽  
Control Value ◽  
Average Ratio ◽  
Induce Lung Injury ◽  
Right Pulmonary Artery ◽  
The Right

A total of 22 sheep with lymphatic cannulas were used to determine if 99mTc-labeled diethylenetriaminepentaacetic acid (DTPA) clears directly from the air spaces of the lungs into the lymph vessels. Each sheep was anesthetized and ventilated with an aerosol of the DTPA for 2–5 min, and the DTPA activities in the lymph and plasma were measured every 15 min for 2 h. After the first 45 min, the average ratio of the DTPA in the lymph to that in the plasma (L/P) was 1.03 +/- 0.06 (SD) in the six control experiments and 1.11 +/- 0.05 in the six experiments in which the lungs were inflated with a positive end-expired pressure of 10 cmH2O throughout the study. Direct movement of the DTPA from the air spaces into the lymph was not necessary to account for the DTPA clearance in these experiments because the L/P ratio was not significantly different from 1.0. Eight additional sheep received intravenous infusions of air at 0.2 ml.kg-1.min-1 for 2 h to induce lung injury before depositing the DTPA. In these sheep L/P was 1.53 +/- 0.28, which was significantly higher than the value measured in the control group (P less than 0.01). We considered the possibility that the increased L/P ratio in these sheep could be due to alterations in the distribution of the blood flow to the tissue, but the L/P ratio in four sheep whose distribution of blood flow was altered by inflation of a balloon in the right pulmonary artery was 1.05 +/- 0.10, the same as the control value.(ABSTRACT TRUNCATED AT 250 WORDS)

Ischemia-reperfusion lung injury in rabbits: mechanisms of injury and protection

1999 ◽  
Vol 276 (1) ◽  
pp. L137-L145 ◽  
Author(s):  
Tsutomu Sakuma ◽  
Keiji Takahashi ◽  
Nobuo Ohya ◽  
Osamu Kajikawa ◽  
Thomas R. Martin ◽  
...  
Keyword(s):  
Lung Injury ◽  
Pulmonary Edema ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Rabbit Model ◽  
Left Lung ◽  
Lung Water ◽  
Lung Inflation ◽  
Ultrastructural Studies

To study the mechanisms responsible for ischemia-reperfusion lung injury, we developed an anesthetized rabbit model in which the effects of lung deflation, lung inflation, alveolar gas composition, hypothermia, and neutrophils on reperfusion pulmonary edema could be studied. Rabbits were anesthetized and ventilated, and the left pulmonary hilum was clamped for either 2 or 4 h. Next, the left lung was reperfused and ventilated with 100% oxygen. As indexes of lung injury, we measured arterial oxygenation, extravascular lung water, and the influx of a vascular protein (131I-labeled albumin) into the extravascular space of the lungs. The principal results were that 1) all rabbits with the deflation of the lung during ischemia for 4 h died of fulminant pulmonary edema within 1 h of reperfusion; 2) inflation of the ischemic lung with either 100% oxygen, air, or 100% nitrogen prevented the reperfusion lung injury; 3) hypothermia at 6–8°C also prevented the reperfusion lung injury; 4) although circulating neutrophils declined during reperfusion lung injury, there was no increase in interleukin-8 levels in the plasma or the pulmonary edema fluid, and, furthermore, neutrophil depletion did not prevent the reperfusion injury; and 5) ultrastructural studies demonstrated injury to both the lung endothelium and the alveolar epithelium after reperfusion in deflated lungs, whereas the inflated lungs had no detectable injury. In summary, ischemia-reperfusion injury to the rabbit lung can be prevented by either hypothermia or lung inflation with either air, oxygen, or nitrogen.

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