Experimental studies on the effect of total thoracic esophagectomy on cardiorespiratory functions and the plasma concentration of chemical mediators.

To examine the effects of total thoracic esophagectomy on cardiorespiratory functions and the responses of the body to surgery, changes in the cardiorespiratory parameters and plasma concentrations of chemical mediators were examined before and after surgery in 21 mongrel dogs inflicted with 3 types of surgical damage. Group 1 underwent a simple thoracotomy, Group 2 an ablation around the thoracic esophagus and pulmonary hilus, and Group 3 a total thoracic esophagectomy with extended lymphnode dissection around the tracheobronchial region. In Group 3, lung resistance and extravascular lung water increased by 108 per cent and 83 per cent, respectively, while lung compliance decreased by 71 per cent. Among the cardiovascular parameters, pulmonary arterial pressure and pulmonary wedge pressure increased by 40 per cent and 89 per cent, respectively, these values being significantly higher in this group than in the other two groups. With regard to the plasma chemical mediators, renin-angiotensin-aldosterone, antidiuretic hormone, catecholamine, serotonin, histamine, and thromboxane B2 levels were significantly higher in Group 3 than in Group 1. The increase in thromboxane B2 was particularly notable in Group 3, being about 6,000 pg/ml 60 minutes after surgery. The results of this study showed how total thoracic esophagectomy lead to a marked deterioration in respiratory function caused by division of the pulmonary nerves and changes in plasma chemical medicator concentrations which induced constriction of the pulmonary vessels and/or increased the vascular permeability. The disturbance of pulmonary lymph flow due to surgical disruption of the lymphatic system also contributed to the deteriorated lung function.