Measuring Thoracic Gas Compression
During exhalation air flow occurs because of the pressure difference between the alveoli and the surrounding atmosphere. The increase in alveolar pressure acts to compress the air inside the lung a…
Category pftblog
It’s all about FEV1, except when it isn’t.
A number of physicians and researchers I’ve known and respected have said that in spirometry it always comes down to FEV1 since it is the primary indicator for airway obstruction. Certainly F…
One more DLCO technique: DLCO measured during exhalation (Intrabreath DLCO)
There have been numerous criticisms of the single-breath DLCO technique, many of them quite valid. In particular, the standard equation for calculating DLCO makes no consideration for the inspirato…
Selecting a DLCO test in order to show airway obstruction
When DLCO tests are performed my lab’s standard policy to average two or more results that meet the criteria for quality and reproducibility. It is not unusual for us to perform three DLCO te…
How should predicted TLC and RV be derived?
The ATS-ERS standards on lung volume measurements says that measured TLC and RV can be calculated either by RV = FRC – ERV then TLC = RV + SVC or by TLC = FRC + IC then RV = TLC – SVC with the pref…
LOINC, and why it matters to your HIS Interface
The Hospital Information Systems (HIS) at different medical centers have grown up mostly in isolation from each other. Even when an HIS is installed by a national vendor, each individual hospital h…
Using an HIS Interface as your report manager
The last several decades has seen a complete transition to the use of computers in pulmonary function testing. This has improved Lab efficiency, but it is also the new baseline. Further improvement…
Exhaled air temperature and Asthma
One of the hallmarks of chronic asthma is airway inflammation. This frequently causes an increase in the perfusion of the airways which in turn can appear as an increased DLCO in routine PFTs. A nu…
DLCO: Sample balloon versus real-time gas analysis
The manager of a nearby PFT Lab made an interesting statement recently, and that was that DLCO measurements made with a sample balloon were superior to those made with a real-time gas analyzer. I t…
The GLFI TLCO Task Force is open for business
Late in 2012 the Global Lung Function Initiative (GLFI) released their reference equations for spirometry. Although not without some criticism this was an important step towards the development of …