Optimal size matching in single lung transplantation

Background: Single lung transplantation for patients with end-stage obstructive lung disease has been highly effective in providing symptomatic relief, and it has been performed at a much increased frequency since 1983. However, there still lacks a convincing study showing the effect of size match and other preoperative variables in predicting functional outcome of patients after transplantation. Methods: We evaluated 23 single lung transplantations performed for obstructive lung disease over a 34-month period. Multiple physiologic variables and size match criteria were evaluated for their contribution in determining the postoperative forced expiratory volume in 1 second at 3 months after transplantation. Results: The size match ratio that was based on intramammary chest wall circumference was the most useful criterion to adopt, and the optimal donor/recipient size match ratio was 0.89. Furthermore, forced expiratory volume in 1 second at 3 months after transplantation could be predicted with a simple mathematical model that was based on the size match ratio and the recipient's calculated vital capacity of the transplanted hemithorax. Conclusion: This model could be applied in a clinical setting to maximize functional outcome of the recipients undergoing single lung transplantation.