[Respiratory function and pulmonary thromboxane release after total thoracic esophagectomy].

In experimental studies using mongrel dogs, 60 minutes after total thoracic esophagectomy the dog lung transiently released into the systemic circulation up to about 6000 micrograms/ml of thromboxane A2(TXA2) measured by radioimmunoassay as its metabolite thromboxane B2(TXB2). To determine whether lung TX release had effects on pulmonary function, we measured the changes in extravascular lung water (EVLW), lung resistance (RL) before, 10, 30, and 60 minutes after total thoracic esophagectomy in 14 anesthetized dogs. In seven untreated dogs, EVLW and RL increased and CL decreased approximately twofold at 60 minutes after the surgery, which corresponded well with a large transpulmonary plasma concentration gradient of TXB2. In remaining 7 dogs pretreated with intravenous OKY-046 which was TXA2 synthetase inhibitor, increase in EVLW and RL and decrease in CL were minimal and plasma concentration of TXB2 remained low value of a preoperative level. In clinical studies, 20 patients with esophageal carcinoma were evaluated. All of these patients underwent total thoracic esophagectomy with extended lymph node dissection of a similar extent. In 5 control patients, significant increase in EVLW and pulmonary vascular resistance were noted at 60 minutes after surgery. On the other hand, while the patients who had intravenous OKY-046 administration during operation at a dose of 1 microgram/kg/min or 5 micrograms/kg/min showed significant decrease in EVLW and pulmonary vascular resistance at 60 minutes after surgery. Based on these results, it is concluded that TXA2 appears to be one of the most important factors to cause the postoperative pulmonary complication after total thoracic esophagectomy for esophageal cancer.