Pulmonary function after heart-lung transplantation using larger donor organs.

Restrictive pulmonary function after heart-lung transplantation (HLT) has been attributed to the use of smaller donor lungs and/or an inability to generate normal negative pleural pressures. Pleural pressure generation depends on both the size of the recipient thoracic cage and its neuromuscular integrity. To determine whether lung volumes after heart-lung transplantation are more dependent on donor lung size or on recipient chest wall characteristics, seven HLT recipients were evaluated before and after transplantation. Postoperative values initially (average, 2 months), 6, and 12 months after transplantation were compared with predicted lung volumes for the recipient and donor organs. TLC dropped from a mean of 5.2 +/- 0.5 L preoperatively to 3.7 +/- 0.3 L (p less than 0.05) 2 months after HLT, but it improved with time and ultimately was not different from preoperative values. The predicted TLC of the HLT donor organs were significantly larger than those of the recipient's predicted TLC, with a mean of 6.9 +/- 0.4 versus 5.3 +/- 0.3 L (p less than 0.05). DLCO, arterial PO2, and PCO2 did not change after surgery. Within limits, larger donor lungs appear to adapt to the constraints of the recipient chest and may be used with clinical success, without apparent adverse effects.