title: Ventilation-perfusion relationships following experimental pulmonary contusion.
abstract: Ventilation-perfusion changes after right-sided pulmonary contusion (PC) in swine were investigated by means of the multiple inert gas elimination technique (MIGET). Anesthetized swine (injury, n = 8; control, n = 6) sustained a right-chest PC by a captive-bolt apparatus. This was followed by a 12-ml/kg hemorrhage, resuscitation, and reinfusion of shed blood. MIGET and thoracic computed tomography (CT) were performed before and 6 h after injury. Three-dimensional CT scan reconstruction enabled determination of the combined fractional volume of poorly aerated and non-aerated lung tissue (VOL), and the mean gray-scale density (MGSD). Six hours after PC in injured animals, Pa(O(2)) decreased from 234.9 +/- 5.1 to 113.9 +/- 13.0 mmHg. Shunt (Q(S)) increased (2.7 +/- 0.4 to 12.3 +/- 2.2%) at the expense of blood flow to normal ventilation/perfusion compartments (97.1 +/- 0.4 to 87.4 +/- 2.2%). Dead space ventilation (V(D)/V(T)) increased (58.7 +/- 1.7% to 67.2 +/- 1.2%). MGSD increased (-696.7 +/- 6.1 to -565.0 +/- 24.3 Hounsfield units), as did VOL (4.3 +/- 0.5 to 33.5 +/- 3.2%). Multivariate linear regression of MGSD, VOL, V(D)/V(T), and Q(S) vs. Pa(O(2)) retained VOL and Q(S) (r(2) = .835) as independent covariates of Pa(O(2)). An increase in Q(S) characterizes lung failure 6 h after pulmonary contusion; Q(S) and VOL correlate independently with Pa(O(2)).
authors.affiliation: U.S. Army Institute of Surgical Research, 3400 Rawley E. Chambers Ave., Fort Sam Houston, Texas 78234-6315, USA. andriy.batchinsky@amedd.army.mil
authors.forename: Andriy I
authors.initials: AI
authors.lastname: Batchinsky
authors.forename: William B
authors.initials: WB
authors.lastname: Weiss
authors.forename: Bryan S
authors.initials: BS
authors.lastname: Jordan
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Dick
authors.forename: David A
authors.initials: DA
authors.lastname: Cancelada
authors.forename: Leopoldo C
authors.initials: LC
authors.lastname: Cancio
mesh_terms: D000818:Animals; D003288:Contusions / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D021621:Imaging, Three-Dimensional; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D055370:Lung Injury; D010100:Oxygen / Q000502:physiology; D013552:Swine; D014057:Tomography, X-Ray Computed; D014692:Ventilation-Perfusion Ratio / Q000502:physiology*
chemical_list: D010100:Oxygen