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The Pattern of Early Lung Parenchymal and Air Space Injury Following Acute Blood Loss
Author(s) -
Younger John G.,
Taqi Ali S.,
Jost Peter F.,
Till Gerd O.,
Johnson Kent J.,
Stern Susan A.,
Hirschl Ronald B.
Publication year - 1998
Publication title -
academic emergency medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.221
H-Index - 124
eISSN - 1553-2712
pISSN - 1069-6563
DOI - 10.1111/j.1553-2712.1998.tb02482.x
Subject(s) - medicine , parenchyma , air space , lung , intensive care medicine , pathology , emergency medicine , aerospace engineering , engineering
. Acute lung injury is a frequent clinical occurrence following blood loss and trauma. The nature of this injury remains poorly understood. Objective : To examine the relative parenchymal and intra‐al‐veolar distribution of inflammation in a rat model of hemorrhage and resuscitation. Methods : Rats were anesthetized and subjected to hemorrhage followed by resuscitation with shed blood and saline. Myelo‐peroxidase activity of lung homogenates and cytology of bronchoalveolar lavage fluid were used to measure total lung and intra‐alveolar neutrophil invasion. Extravasation of IV‐administered [ 125 I]‐albumin was used to determine total lung and alveolar permeability. Permeability results were analyzed using their base‐10 logarithmic transformations. Results : 86 animals were studied. Whole‐lung myeloperoxidase activity was increased (control = 0.34 ± 0.16 units, injured = 0.84 ± 0.43 units, p < 0.01), while there was no difference in intra‐alveolar leukocyte counts (injured = 1.85 ± 1.30 times 10 5 mL, control = 2.44 ± 1.75 times 10 5 mL, p = 0.40), suggesting that the cellular component of the injury was more severe in the intravas‐cular and interstitial spaces. There was a strong trend toward increased permeability in the interstitial compartment, and a significant increase in permeability in the intra‐alveolar compartment (whole‐lung permeability: control =—0.27 ± 0.19 units, injured = 0.10 ± 0.55 units, p = 0.06; alveolar permeability: control = ‐2.00 ± 0.47 units, injured = ‐1.32 ± 0.49 units, p < 0.01), suggesting that the loss of integrity to macromolecules was not limited to the interstitium. Conclusion : Hemorrhage and resuscitation resulted in an acute lung injury characterized by extravasation of intravascular protein into both the interstitium and the intra‐alveolar space. Neutrophil invasion of the lung was demonstrable only in the interstitial compartment.