Selective Assessment of Single-Lung Graft Function With ¹³³Xe Radiospirometry in Acute Rejection and Infection

¹ From the Department of Thoracic and Cardiovascular Surgery, Helsinki University Central Hospital, Helsinki, Finland
² From the Department of Internal Medicine, Helsinki University Central Hospital, Helsinki, Finland

In single-lung transplant recipients, the usefulness of spirometric indexes in detecting acute events involving the lung graft is limited due to the bias caused by the native lung. Selective functional monitoring is needed for the proper evaluation of complications after transplantation, but thus far, to our knowledge, no clinically feasible methods for selective graft-function assessment have been presented. In ten single-lung recipients, of whom six had a parenchymal lung disease and four had pulmonary hypertension, the relative ventilation (Vtx), perfusion (Qtx), and ventilation/perfusion ratio of the transplanted lung (V/Qtx) were determined with multidetector ¹³³Xe radiospirometry. Additionally, the fractions of FEV₁, FVC, and diffusing capacity for carbon monoxide (Dco) of the transplant (FEV₁tx, FVCtx, Dcotx, respectively) were determined by using corresponding radiospirometric parameters for the calculation of their distribution between the lungs. The analysis included seven episodes of acute rejection and nine episodes of infection. The Qtx decreased during acute rejection but did not change during infection (p=0.001). Compared with the figures during infection, the V/Qtx increased during acute rejection significantly (p<0.05) in patients with underlying fibrosis or emphysema, but not in those with pulmonary hypertension. In detection of acute events, the sensitivity of the selective parameters, ie, FEV₁tx (86%) and FVCtx (73%), was higher than that of the sum-function parameters, FEV₁ (66%) and FVC (40%). Moreover, the sensitivity of Dcotx (80%) was higher than that of Dco (60%) in detecting acute rejection. The findings indicate that, in single-lung recipients with a parenchymal lung disease, the assessment of Qtx, V/Qtx, and Dcotx with a radioactive tracer can help to distinguish acute rejection from infection. The graft-selective parameters, ie, FEV₁tx, FVCtx, and Dcotx, tended to be more sensitive than the corresponding sum-function parameters in detecting acute events, thus providing a more accurate functional profile of the single-lung graft.

Key Words: acute allograft rejection • diffusing capacity of the lung • lung function tests • lung transplantation • radiospirometry • spirometry

Submitted on March 1, 1995
Accepted on November 27, 2007

This article has been cited by other articles:

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