It has been shown  that children actually have better function with mature lobar transplants than age and size matched immature lungs (Kern et al, Ann Thorac Surg 57(5):1089-1094). However, there is some doubt that the mature pulmonary grafts will function efficiently in gas exchange in recipients as they grow (Duebener et al Ann Thorac Surg 1999 68(4):1165-70). Starnes et al (Ann Thorac Surg 1999 68(6):2279-83) on the contrary, has found that at 2 years post-transplant pediatric recipients who received living related lobes fare better than those with cadaveric transplants, as judged by the onset of rejection. 

The biggest problem with living related lobar transplants is that up to two healthy people have to undergo major surgery with some loss in lung function incurred in order to benefit one very unhealthy recipient.Donors have a 16% decrease( right lower lobe) and 18% decrease (left lower lobe) in vital capacity.(Woo et al. Pediatric Transplant 1998 2(3):185-90. They also have a significant recovery time with subsequent loss of wages. This poses an ethical dilemma for doctors who are put in the position of putting two lives at risk. Dr. Trulock of Barnes in St.Louis stated at the Secondwind meeting that he would only consider this procedure if a child's life was at stake. Only children and small adults can benefit from this procedure. A lobar transplant could not fill the chest space of a normal sized adult.