Experimental study on size matching in a canine living-donor lobar lung transplant model

In an effort to address the donor-shortage issue, living-donor lobar lung transplants have been performed with satisfactory results. The use of small grafts is potentially problematic because it could cause high pulmonary artery pressure, resulting in lung edema. The purpose of this study was to evaluate the effect of small grafts on early pulmonary function and to identify the predictor for acceptable size discrepancy.

Seventeen pairs of mongrel dogs with various donor-recipient sizes were used. Body weight, height, chest circumference, and lung weight were measured as size parameters. Right middle, lower, and cardiac lobes were implanted as a right lung of the recipient and the left lower lobe was implanted as a left lung without use of cardiopulmonary bypass. Pulmonary function of the recipient was measured for 6 hours after reperfusion.

A significant negative correlation was found between donor/recipient body-weight ratio and mean pulmonary artery pressure at 1 hour (r = -0.594, P =.025). A significant correlation was found between donor/recipient body-weight ratio and PaO(2) at 6 hours (r = 0.704; P =.007). There was no significant correlation between the other 3 size parameters and postoperative pulmonary function. All 8 recipients with a donor/recipient body-weight ratio of 1.2 or greater survived the 6-hour assessment period, and their PaO(2) exceeded 500 mm Hg at 6 hours.

Donor/recipient weight ratio is an important predictor of early pulmonary function in a canine living-donor lobar lung transplant model.