"Horses for courses" computed tomography or predicted total lung capacity for size matching in lung transplantation

Abstract

Size-matching donors to recipients in lung transplantation continues to be a clinical challenge. Predicted total lung capacity equations, or more simply, donor and recipient heights, while widely used, are imprecise and may not be representative of the pool of donors and recipients. These inherent limitations may result in size discrepancies. The advent of easily accessible software and the widespread availability of computed tomography (CT) imaging in donor assessments have made it possible to directly measure lung volumes in donors and recipients. As a result, there is a growing interest in adopting personalized CT volumetry as an alternative. This article explores both methods and underscores the potential benefits and precision offered by CT.

Keywords: computed tomography; donor assessment; lung transplantation; predicted total lung capacity; size matching.

Figure 1:

Predicted total lung capacity with its 95 % confidence interval from age 12 to 80 for males with a height of 175 cm.

Figure 2:

Risk of size mismatch when using the Global Lung Initiative predictive equations and minimum and maximum donor-recipient ratios from 0.8 to 1.2. Panel A: A 50 yo, 175 cm tall, male recipient would be size mismatched approximately 5% of the time. Panel B: The same recipient has a 50% probability of size mismatch if matched to a donor with a predicted total lung capacity of 7.4 liters, donor to recipient ratio: 1.2.

Figure 3:

The total lung capacity measured by each method is different: computed tomography volumetry can measure the volume of each hemithorax; gas dilution techniques measure ventilated alveolar volume; plethysmography measures all air space distal to the device shutter valve.