SERIES “ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING” 

Edited by V. Brusasco, R. Crapo and G. Viegi 

Number 5 in this Series 







This section is written to provide guidance in interpreting pulmonary function tests (PFTs) to medical directors of hospital-based laboratories that perform PFTs, and physicians who are responsible for interpreting the results of PFTs most commonly ordered for clinical purposes. Specifically, this section addresses the interpretation of spirometry, bronchodilator response, carbon monoxide diffusing capacity ( D L,CO) and lung volumes.

The sources of variation in lung function testing and technical aspects of spirometry, lung volume measurements and D L,CO measurement have been considered in other documents published in this series of Task Force reports 1–4 and in the American Thoracic Society (ATS) interpretative strategies document 5.

An interpretation begins with a review and comment on test quality. Tests that are less than optimal may still contain useful information, but interpreters should identify the problems and the direction and magnitude of the potential errors. Omitting the quality review and relying only on numerical results for clinical decision making is a common mistake, which is more easily made by those who are dependent upon computer interpretations.

Once quality has been assured, the next steps involve a series of comparisons 6 that include comparisons of test results with reference values based on healthy subjects 5, comparisons with known disease or abnormal physiological patterns ( i.e. obstruction and restriction), and comparisons with self, a rather formal term for evaluating change in an individual patient. A final step in the lung function report is to answer the clinical question that prompted the test.

Poor choices made during these preparatory steps increase the risk of misclassification, i.e. a falsely negative or falsely positive interpretation for a lung function abnormality or a change …

https://erj.ersjournals.com/content/erj/26/5/948.full.pdf

Interpretative strategies for lung function tests

[⇓][1] 

SERIES “ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING” 

Edited by V. Brusasco, R. Crapo and G. Viegi 

Number 4 in this Series

 [1]: #F4

/pdf/standardisation-of-the-single-breath-determination-of-carbon-22bp5iqq0t.pdf

Standardisation of the single-breath determination of carbon monoxide uptake in the lung

The American Thoracic Society/European Respiratory Society jointly created a Task Force on "Outcomes for COPD pharmacological trials: from lung function to biomarkers" to inform the chronic obstructive pulmonary disease research community about the possible use and limitations of current outcomes and markers when evaluating the impact of a pharmacological therapy. Based on their review of the published literature, the following document has been prepared with individual sections that address specific outcomes and markers, and a final section that summarises their recommendations.

/pdf/outcomes-for-copd-pharmacological-trials-from-lung-function-4a4k924y7q.pdf

Outcomes for COPD pharmacological trials: From lung function to biomarkers

⇓“The tantalizing problem of the connective link in cirrhotic patients between oxygen unsaturation and possible arteriovenous shunting in the lungs remains unsolved, and any relation between arterial unsaturation and pulmonary vasodilation remains obscure.”



Fig. 1.— 
Working model of molecular alterations in the pulmonary microcirculation in experimental hepatopulmonary syndrome (HPS). a) In the normal microvasculature, a balance of vasoconstrictive and vasodilatory factors, including paracrine endothelin (ET)-1-mediated vasoconstriction through the ETA receptor (▪) on smooth muscle cells (SMCs) and ET-1-mediated vasodilatation mediated through the ETB receptor (□) linked to endothelial nitric oxide synthase (eNOS) in endothelial cells (ECs), maintain tone. b) During the development of HPS, a number of alterations, both directly and indirectly related to hepatic injury and portal hypertension, result in the production or release of mediators into the venous circulation, where they influence the pulmonary microcirculation. Increased expression of pulmonary endothelial ETB receptors and increased hepatic production and release of ET-1 contribute to an increase in eNOS expression and enhanced nitric oxide (NO) production in the microvascular endothelium during the initiation of HPS. Tumour necrosis factor (TNF)-α-mediated accumulation of intravascular macrophage-like cells also occurs after chronic common bile duct ligation. Haem oxygenase (HO)-1 and inducible nitric oxide synthase (iNOS) expression increase in these cells and contribute to the progression of HPS. CO: carbon monoxide.





Fig. 2.— 
Algorithm for screening and therapeutic decisions in hepatopulmonary syndrome (HPS). OLT: orthotopic liver transplantation; P a,O2: arterial oxygen tension; P A–a,O2: alveolar–arterial oxygen tension difference; CEE: contrast-enhanced echocardiography; PFT: pulmonary function test; MAA: macroaggregated albumin. #: high-resolution thoracic computed tomographic scanning is highly recommended in order to exclude chronic respiratory comorbid conditions; ¶: high risk for post-operative OLT mortality. 1 mmHg=0.133 kPa.





Fig. 3.— 
Plot demonstrating the relationship between cardiac output ( Q ') and transpulmonary pressure gradient (TPG; mean pulmonary arterial …

https://erj.ersjournals.com/content/erj/24/5/861.full.pdf

Pulmonary–Hepatic vascular Disorders (PHD)

There are numerous reference equations available for the single-breath transfer factor of the lung for carbon monoxide ( T  LCO ); however, it is not always clear which reference set should be used in clinical practice. The aim of the study was to develop the Global Lung Function Initiative (GLI) all-age reference values for T  LCO . Data from 19 centres in 14 countries were collected to define T  LCO reference values. Similar to the GLI spirometry project, reference values were derived using the LMS (lambda, mu, sigma) method and the GAMLSS (generalised additive models for location, scale and shape) programme in R. 12 660 T  LCO measurements from asymptomatic, lifetime nonsmokers were submitted; 85% of the submitted data were from Caucasians. All data were uncorrected for haemoglobin concentration. Following adjustments for elevation above sea level, gas concentration and assumptions used for calculating the anatomic dead space volume, there was a high degree of overlap between the datasets. Reference values for Caucasians aged 5–85 years were derived for T  LCO , transfer coefficient of the lung for carbon monoxide and alveolar volume. This is the largest collection of normative T  LCO data, and the first global reference values available for T  LCO .

https://erj.ersjournals.com/content/erj/50/3/1700010.full.pdf

Official ERS technical standards: Global Lung Function Initiative reference values for the carbon monoxide transfer factor for Caucasians

Because of unanswered questions about prediction equations for the single-breath carbon monoxide diffusing capacity (DlCO) and as part of a larger collaborative project, standardized DlCO measurements were carried out in a selected sample of 361 healthy nonsmoking volunteers (194 men and 167 women) living in the Barcelona metropolitan area (Spain). Except for the test FiO2 (0.18), the study essentially followed the American Thoracic Society (ATS) and European Community for Coal and Steel (ECCS) recommendations for standardizing the methodology of measuring DlCO. Prediction equations for ages 20 through 70 were calculated separately for both sexes. Simple linear equations using age, height, and body weight as independent variables predicted the DlCO indices (DlCO, Va, and Dl/Va) as well as more complex equations. In addition, a complete analysis of the residuals (predicted measured values) showed that the assumptions of the multiple regression analysis (independence, homoscedasticity and Gaussian distribut...

Joaquim Perez

Papers

Single-breath carbon monoxide diffusing capacity prediction equations from a Mediterranean population.