PLASMA THROMBOXANE B2 CONCENTRATIONS AND PULMONARY VASCULAR-RESISTANCE DURING LUNG REPERFUSION

The purpose of this study was to measure the behavior of plasmatic thr omboxane B-2 (pITxB(2)) after reperfusion of a glucose-insulin-potassi um) preserved lung. Seven adult mongrel dogs underwent a left lung all otransplantation. Hemodynamic changes including pulmonary artery press ure and cardiac output were measured. Pulmonary artery vascular resist ance, systemic resistance, arterio-venous oxygen difference, and shunt were calculated. Immunoreactive arterial and venous plasma thromboxan e B-2 concentrations were measured at 0 (basal), 60, 120, and 180 min after reperfusion. Hemodynamic measurements were made after 5 min of o cclusion of the right pulmonary artery and ventilation with 100% oxyge n. Prepreservation, pre-reperfusion, and posttransplant lung weights w ere obtained. All animals survived the procedure. Ischemic time was 14 .72 (+/-0.31) h. Cardiac output, systemic arterial pressure, and arter io-venous oxygen difference decreased while systemic vascular resistan ce, pulmonary vascular resistance, and shunt increased during the stud y. Mean pulmonary artery pressure correlated with pulmonary vascular r esistance (P<.01). Oxygen tension diminished significantly at 180 min after reperfusion. Mean basal pulmonary arterial TxB(2) was 3589 (+/-4 24) pg/ml; mean plasma pulmonary venous TxB(2) was 6578 (+/-1571) pg/m l. Pulmonary arterial to venous TxB(2) ratio (a/vTxB(2)) increased fro m 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 TxB(2) had a positi ve correlation with mean pulmonary artery pressure (P<.05); also, a/v pITxB(2) correlated with pulmonary vascular resistance (r=.616, p<.01) . Mean post-reperfusion lung weight increase was 74.88% (45.37 g). In conclusion, pITxB(2) a/v ratio ratio increases after reperfusion of a 14-h preserved lung; pulmonary vascular resistance significantly incre ases after 180 min of reperfusion and correlates with the increase in pITxB(2) a/v ratio.