Plasma Thromboxane B2 Concentrations and Pulmonary Vascular Resistance During Lung Reperfusion

Abstract

The purpose of this study was to measure the behavior of plasmatic thromboxane B2 (pIT×B₂) after reperfusion of a glucose-insulin-potassium preserved lung. Seven adult mongrel dogs underwent a left lung allotransplantation. Hemodynamic changes including pulmonary artery pressure and cardiac output were measured. Pulmonary artery vascular resistance, systemic resistance, arterio-venous oxygen difference, and shunt were calculated. Immunoreactive arterial and venous plasma thromboxane B₂ concentrations were measured at 0 (basal), 60, 120, and 180 min after reperfusion. Hemodynamic measurements were made after 5 min of occlusion of the right pulmonary artery and ventilation with 100% oxygen. Prepreservation, pre-reperfusion, and posttransplant lung weights were obtained. All animals survived the procedure. Ischemic time was 14.72 (50.31) h. Cardiac output, systemic arterial pressure, and arterio-venous oxygen difference decreased while systemic vascular resistance, pulmonary vascular resistance, and shunt increased during the study. Mean pulmonary artery pressure correlated with pulmonary vascular resistance (p<.01). Oxygen tension diminished significantly at 180 min after reperfusion. Mean basal pulmonary arterial T×B₂ was 3589 (±424) pg/ml; mean plasma pulmonary venous T×B₂ was 6578 (±1571) pg/ml. Pulmonary arterial to venous T×B₂ ratio (a/vT×B₂) increased from 0.70 at basal measurement to 0.83 at 60 min, and 0.99 at 120 and 180 min after reperfusion (p<.05). Pulmonary arterial T×B₂ had a positive correlation with mean pulmonary artery pressure (p<.05); also, a/v pIT×B₂ correlated with pulmonary vascular resistance (r =. 616, p<.01). Mean post-reperfusion lung weight increase was 74.88% (45.37 g). In conclusion, pIT×B₂ a/v ratio ratio increases after reperfusion of a 14-h preserved lung; pulmonary vascular resistance significantly increases after 180 min of reperfusion and correlates with the increase in pIT×B₂ a/v ratio.

Key Words:

• ischemia-reperfusion
• lung preservation
• lung reperfusion
• pulmonary resistance
• thromboxane