[Extravascular lung water content following thoracic vagotomy. Experimental investigations in relation to the cause of pulmonary complications after surgery for esophageal cancer].

In order to investigate the relationship between postoperative pulmonary complications after surgery for esophageal cancer and surgical injury to the thoracic vagus nerves, changes of the extravascular lung water volume (EVLW) were studied in 26 mongrel dogs. Two protocols of experiment were designed as follows. In Experiment I (18 dogs), EVLW was measured before and on successive three days after thoracic vagotomy or sham operation. In Experiment II (8 dogs), responses of EVLW to the volume load of saline were studied in previously vagotomized or sham-operated dogs. The measurement of EVLW was performed by thermal-green dye double indicator dilution method. The results obtained were as follows. Values of EVLW as measured by thermal-green dye double indicator dilution method were extremely well correlated with those determined by gravimetric method. After vagotomy, EVLW increased successively. Rate of the increase was greater in dogs with bilateral vagotomy than in those with unilateral vagotomy on the right side. Measurement of various hemodynamics and oncotic pressure revealed no differences between vagotomized and sham-operated dogs. These observations suggested that the increase of EVLW was due to enhanced permeability of the pulmonary capillary wall. The volume load of saline resulted in increase of EVLW in vagotomized dogs, while no changes were observed in sham-operated dogs. The results of the current investigations indicate that the injury to the vagus nerves during surgery for esophageal cancer may induce water retention in the lung, which may be one of the underlying mechanisms of postoperative pulmonary complications.