Changes in lung function after routine exposure manipulations during thoracotomy

The effect of manual retraction and bronchial occlusion upon right lung function during a 2-hr thoracotomy was evaluated in sheep. Group 1 (seven sheep) underwent manual lung retraction. Group 2 (seven sheep) underwent right bronchial occlusion. Group 3 (seven sheep) served as controls. Radioisotopic indicators (51Cr-RBC, 125I-albumin, [14C]urea, 3H2O) were used to assess changes in capillary permeability-surface area product (PS-urea), extravascular lung water (VE), and intravascular blood volume (Vv). Lung water was further quantified by gravimetric technique. Pulmonary vascular resistance increased following thoracotomy in both groups (34% Group 1, 66% Group 2) and compliance decreased (16% Group 1, 33% Group 2). Mean right lung shunt increased in Group 1 from 17 to 37% (P less than 0.05) and for Group 2 from 18 to 36% (P less than 0.02). A reduction (greater than 25%) in both groups for PS-urea and VE occurred (P less than 0.05). The fall in PS-urea and VE and the increase in PVR indicate a reduction in the right lung perfusion for both groups. It is concluded that a similar marked reduction in ventilation, perfusion, and V/Q occurred after reexpansion whether the lung was retracted or the bronchus occluded.