[Natural history of experimental pulmonary atelectasis in dogs with closed chest].
In order to establish an animal model of pulmonary vasoconstriction we followed the time course of intrapulmonary shunt (Qs/Qt) in a canine model of lobar atelectasis with closed chest. Ten mongrel dogs were studied. Bronchial occlusion of the right lower lobe (RLL) was performed by inflating the balloon of a Foley catheter placed through a rigid bronchoscopy. Analysis of variance was used for statistical analysis. (15 minutes) After occlusion Qs/Qt reached its maximum increasing from 8.2 +/- 3.6 to 29.7 +/- 11.7% (p less than 0.05) and PaO2 decreased from 357 +/- 49 to 100 +/- 43 mm Hg (p less than 0.05). Afterwards, there was a progressive decline of Qs/QT accompanied by an also progressive increase in PaO2. At the end of the experiment (3 hrs post atelectasis) Qs/Qt was 11.2 +/- 4.9 and PaO2 251 +/- 124 mm Hg (p less than 0.05). Pulmonary vascular resistance increased post atelectasis from 439 +/- 168 to 598 +/- 256 d.s.cm-5 (p less than 0.05). Complete atelectasis of the RLL was confirmed postmortem. As the changes in Qs/Qt and PaO2 did not parallel the change in cardiac output we conclude that the mechanism of decrease in Qs/Qt was hypoxic vasoconstriction.
Maxwell
R
R
Servicio de Cardioneumología, Instituto Nacional de Cardiología Ignacio Chávez, México, D.F.
López
R
R
Furuya
M E
ME
Ramírez
J C
JC
Beltrán
U
U
Sandoval
J
J
Lupi Herrera
E
E
D000704:Analysis of Variance; D000818:Animals; D002245:Carbon Dioxide / Q000097:blood; D004285:Dogs; D005260:Female; D006439:Hemodynamics; D006863:Hydrogen-Ion Concentration; D008297:Male; D010100:Oxygen / Q000097:blood; D001261:Pulmonary Atelectasis / Q000503:physiopathology*; D013997:Time Factors
D002245:Carbon Dioxide; D010100:Oxygen
Historia natural de la atelectasia pulmonar experimental en perros a tórax cerrado.