Validation of computed tomography for measuring lung weight

Protti, Alessandro; Iapichino, G.; Milesi, M.; Melis, Valentina; Pugni, Paola; Comini, Beatrice; Cressoni, Massimo; Gattinoni, Luciano

doi:10.1186/s40635-014-0031-0

Cited by 16 publications

(14 citation statements)

References 31 publications

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“… Computed tomography (CT) . For analysis, the lung scans were divided into five axial sections from apex to basal segments, and total lung volume, lung weight, as well as the fractions of over-, well-, poorly, and non-aerated tissue [ 7 – 10 ] were calculated. Recruitability was quantified as the difference between the volume of non-inflated tissue at zero end-expiratory pressure (ZEEP) and at PEEP 15 divided by the volume of non-inflated tissue at ZEEP [ 11 ].…”

Section: Methodsmentioning

confidence: 99%

Effects of regional perfusion block in healthy and injured lungs

Cambiaghi

Vasques

Mörer

et al. 2017

ICMx

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BackgroundSevere hypoperfusion can cause lung damage. We studied the effects of regional perfusion block in normal lungs and in the lungs that had been conditioned by lavage with 500 ml saline and high V T (20 ml kg−1) ventilation.MethodsNineteen pigs (61.2 ± 2.5 kg) were randomized to five groups: controls (n = 3), the right lower lobe block alone (n = 3), lavage and high V T (n = 4), lung lavage, and high V T plus perfusion block of the right (n = 5) or left (n = 4) lower lobe. Gas exchange, respiratory mechanics, and hemodynamics were measured hourly. After an 8-h observation period, CT scans were obtained at 0 and 15 cmH2O airway pressure.ResultsPerfusion block did not damage healthy lungs. In conditioned lungs, the left perfusion block caused more edema in the contralateral lung (777 ± 62 g right lung vs 484 ± 204 g left; p < 0.05) than the right perfusion block did (581 ± 103 g right lung vs 484 ± 204 g left; p n.s.). The gas/tissue ratio, however, was similar (0.5 ± 0.3 and 0.8 ± 0.5; p n.s.). The lobes with perfusion block were not affected (gas/tissue ratio right 1.6 ± 0.9; left 1.7 ± 0.5, respectively). Pulmonary artery pressure, PaO2/FiO2, dead space, and lung mechanics were more markedly affected in animals with left perfusion block, while the gas/tissue ratios were similar in the non-occluded lobes.ConclusionsThe right and left perfusion blocks caused the same “intensity” of edema in conditioned lungs. The total amount of edema in the two lungs differed because of differences in lung size. If capillary permeability is altered, increased blood flow may induce or increase edema.Electronic supplementary materialThe online version of this article (10.1186/s40635-017-0161-2) contains supplementary material, which is available to authorized users.

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Section: Methodsmentioning

confidence: 99%

Effects of regional perfusion block in healthy and injured lungs

Cambiaghi

Vasques

Mörer

et al. 2017

ICMx

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“…After an additional recruitment manoeuvre, a lung CT scan was performed at end expiration with the endotracheal tube clamped, in prone and supine positions. CT scan settings have been described elsewhere [ 16 , 20 ], and lung CT scan-derived lung weight measurement has been previously validated in this same animal model by our group [ 21 ].…”

Section: Methodsmentioning

confidence: 99%

Prone position ameliorates lung elastance and increases functional residual capacity independently from lung recruitment

Santini

Protti

Länger

et al. 2015

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BackgroundProne position is used to recruit collapsed dependent lung regions during severe acute respiratory distress syndrome, improving lung elastance and lung gas content. We hypothesised that, in the absence of recruitment, prone position would not result in any improvement in lung mechanical properties or gas content compared to supine position.MethodsTen healthy pigs under general anaesthesia and paralysis underwent a pressure–volume curve of the respiratory system, chest wall and lung in supine and prone positions; the respective elastances were measured. A lung computed tomography (CT) scan was performed in the two positions to compute gas content (i.e. functional residual capacity (FRC)) and the distribution of aeration. Recruitment was defined as a percentage change in non-aerated lung tissue compared to the total lung weight.ResultsNon-aerated (recruitable) lung tissue was a small percentage of the total lung tissue weight in both positions (4 ± 3 vs 1 ± 1 %, supine vs prone, p = 0.004). Lung elastance decreased (20.5 ± 1.8 vs 15.5 ± 1.6 cmH2O/l, supine vs prone, p < 0.001) and functional residual capacity increased (380 ± 82 vs 459 ± 60 ml, supine vs prone, p = 0.025) in prone position; specific lung elastance did not change (7.0 ± 0.5 vs 6.5 ± 0.5 cmH2O, supine vs prone, p = 0.24). Lung recruitment was low (3 ± 2 %) and was not correlated to increases in functional residual capacity (R2 0.2, p = 0.19). A higher amount of well-aerated and a lower amount of poorly aerated lung tissue were found in prone position.ConclusionsIn healthy pigs, prone position ameliorates lung mechanical properties and increases functional residual capacity independently from lung recruitment, through a redistribution of lung aeration.

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“…After 54 hours, animals were euthanized. Pulmonary edema was diagnosed if final lung weight (measured with a balance) exceeded the initial one (measured with CT) (15). Lung wet-to-dry weight ratio and histology were evaluated as previously described (7)(8)(9).…”

Section: Study Protocolmentioning

confidence: 99%