INCREASES IN PULMONARY-ARTERY PRESSURE AND CARDIAC-OUTPUT DUE TO THE INHIBITION OF NITRIC-OXIDE SYNTHESIS DURING OPERATIVE STRESS

Pulmonary artery pressure (PAP), cardiac output (CO), and urinary nitr ate, a stable endproduct of nitric oxide (NO), were measured pre- and postoperatively in eight patients who underwent esophagectomy for squa mous cell carcinoma of the thoracic esophagus. A significant elevation of PAP and CO on the day of operation (POD 0) was accompanied by a lo w concentration of urinary nitrate, A reduction in PAP and CO, and an increase in nitrate to the preoperative Levels, were found on PODs 2 a nd 3, respectively, but urinary nitrate decreased again after POD 3. C onsequently, the changes in PAP and CO were closely correlated with th e nitrate concentration. These results suggest that operative stress i nhibited NO synthesis with a transitory induction of endogenous NO syn thesis postoperatively.