PFT spirometry, DLCO, lung volume orders
- related: PFT and lung functions
- tags: #literature #boards
Links to this note
If testing includes measuring absolute lung volumes using nitrogen washout, during which 100% O2 is inspired, ample time is required for alveolar O2 levels to return to normal before Dlco maneuvers. This typically implies a time interval at least equal to twice the time required for the nitrogen washout test to be completed. It is therefore recommended that Dlco measurements be made before any multibreath nitrogen washout tests. This issue does not apply when lung volumes are measured utilizing body plethysmography.
Measurement of the single-breath carbon monoxide uptake (Dlco) is informative in the clinical setting, and Dlco measurement standards have recently been updated and published. While inspiring 100% O2 prior to Dlco measurements may affect results, there is no evidence that the administration of bronchodilator will significantly alter the measurement of Dlco. As such, there is no recommendation against the use of bronchodilator prior to Dlco testing. Similarly, studies have not demonstrated that spirometry undertaken prior to Dlco testing will impact measured values.
New terminology introduced in the recent update is the term transfer factor (Tlco). Both Dlco and Tlco are valid terms to describe the carbon monoxide diffusing capacity or transfer factor respectively. They can be used interchangeably, although the term Dlco is still used more commonly in current practice.1
