Effect of tPA on regional lung perfusion in unilobar canine pulmonary thromboembolism.
We investigated effects of tissue-type plasminogen activator (tPA) on regional pulmonary arterial hemodynamics in pulmonary thromboembolism (PTE) in a canine model of unilobar PTE. Ten beagle dogs were divided into two groups-tPA (n = 5) and control group (n = 5). In each dog an artificial blood circuit (ABC) consisting of a silicone tube and a cannulation-type electromagnetic blood flowmeter probe was placed at the left lower pulmonary artery. A unilobar PTE was induced by placing autologous clots into a metallic coil inside the ABC. The CO2 sampling tubes were positioned at the orifice of the left lower bronchus and the trachea, and the end-expiratory CO2 partial pressure (PET(CO2)) was measured. In the tPA group, blood flow at the left lower pulmonary artery (LL-flow) was improved to near baseline within approximately 30 min of receiving tPA, and PET(CO2) at the left lower bronchus (LL-PET(CO2)) increased in direct correlation with LL-flow. The hemodynamic improvement after tPA therapy correlated with the partial pressure of the regional pulmonary expiratory CO2. Moreover, it was suggested that changes in physiologic conditions in PTE were not determined by clot quantity alone.
Ikeda
T
T
Third Department of Internal Medicine, Wakayama Medical College, Japan.
Nakatani
S
S
Takata
H
H
Nosaka
M
M
Yoshikawa
A
A
Tanaka
H
H
Yukawa
S
S
D000818:Animals; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000502:physiology; D004285:Dogs; D004562:Electrocardiography; D010960:Plasminogen Activators / Q000494:pharmacology*; D011651:Pulmonary Artery; D011652:Pulmonary Circulation / Q000187:drug effects*; D011655:Pulmonary Embolism / Q000503:physiopathology*; D011659:Pulmonary Gas Exchange; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*
D002245:Carbon Dioxide; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator