A Method to Derive Lower Limit of Normal for the FEV 1 /Forced Expiratory Volume at 6 s of Exhalation Ratio From FEV 1 /FVC Data

CHEST Journal ◽  
2009 ◽  
Vol 135 (2) ◽  
pp. 408-418 ◽  
Author(s):  
André Capderou ◽  
Malika Berkani ◽  
Marie-Hélèene Becquemin ◽  
Marc Zelter
Keyword(s):  
Lower Limit ◽  
Forced Expiratory Volume ◽  
Lower Limit Of Normal

The lower limit for FEV1/FVC in dive medical assessments: a retrospective study

2021 ◽  
pp. 368-372
Author(s):  
Thijs T Wingelaar ◽  
◽  
Peter-Jan AM van Ooij ◽  
Edwin L Endert ◽  
◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Medical History ◽  
Lower Limit ◽  
Forced Expiratory Volume ◽  
Fitness To Dive ◽  
Diving Medicine ◽  
Function Test ◽  
Z Scores ◽  
Asymptomatic Individuals ◽  
Lower Limit Of Normal

Introduction: Interpreting pulmonary function test (PFT) results requires a valid reference set and a cut-off differentiating pathological from physiological pulmonary function; the lower limit of normal (LLN). However, in diving medicine it is unclear whether an LLN of 2.5% (LLN-2.5) or 5% (LLN-5) in healthy subjects constitutes an appropriate cut-off. Methods: All PFTs performed at the Royal Netherlands Navy Diving Medical Centre between 1 January 2015 and 1 January 2021 resulting in a forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and/or FEV1/FVC with a Z-score between -1.64 (LLN-5) and -1.96 (LLN-2.5) were included. Records were screened for additional tests, referral to a pulmonary specialist, results of radiological imaging, and fitness to dive. Results: Analysis of 2,108 assessments in 814 subjects showed that 83 subjects, 74 men and nine women, mean age 32.4 (SD 8.2) years and height 182 (7.0) cm, had an FVC, FEV1 and/or FEV1/FVC with Z-scores between -1.64 and -1.96. Of these 83 subjects, 35 (42%) underwent additional tests, 77 (93%) were referred to a pulmonary specialist and 31 (37%) underwent high-resolution CT-imaging. Ten subjects (12%) were declared ‘unfit to dive’ for various reasons. Information from their medical history could have identified these individuals. Conclusions: Use of LLN-2.5 rather than LLN-5 for FEV1/FVC in asymptomatic individuals reduces additional investigations and referrals to a pulmonary specialist without missing important diagnoses, provided a thorough medical history is taken. Adoption of LLN-2.5 could save resources spent on diving medical assessments and protect subjects from harmful side effects associated with additional investigations, while maintaining an equal level of safety.

scholarly journals Cardiopulmonary function in adolescent patients with pectus excavatum or carinatum

2021 ◽  
Vol 8 (1) ◽  
pp. e001020
Author(s):  
Salim Ramadan ◽  
Jim Wilde ◽  
Anne Tabard-Fougère ◽  
Seema Toso ◽  
Maurice Beghetti ◽  
...  
Keyword(s):  
Lower Limit ◽  
Pectus Excavatum ◽  
Forced Expiratory Volume ◽  
Cardiopulmonary Function ◽  
Thoracic Imaging ◽  
Systematic Assessment ◽  
Cardiac Functions ◽  
Adolescent Patients ◽  
And Function ◽  
Lower Limit Of Normal

BackgroundPectus excavatum (PE) and pectus carinatum (PC) have generally been considered an aesthetic issue, although there is growing evidence of associated cardiopulmonary function (CPF) impairment, especially in PE patients. The study goal was to determine any correlation between pectus malformations and cardiopulmonary symptoms and function based on systematic assessment of CPF and thoracic measurements, such as Haller Index (HI) and sternal torsion angle (STA).MethodsData from 76 adolescent patients with PE (n=30) or PC (n=46) were retrospectively collected referred between January 2015 and April 2018. CPF measurements and thoracic imaging were performed in all patients. HI and STA correction indexes were measured in all patients.FindingsMedical records from 76 patients (PE n=30; PC n=46) were analysed. Patients were predominantly male (>93.3%), and aged between 13 and 14½ old. PE was associated with airway obstruction, with a forced expiratory volume in 1 s value under the lower limit of normal in 13% of cases (p<0.001). Restrictive syndrome was observed in 23% of cases (p<0.001), with a Z score for total lung capacity under the lower limit of normal. In PC, pulmonary function was not affected. All patients showed slightly decreased values of left and right ejection fraction and cardiac index at rest, although values were within normal range. There were no significant correlations between pulmonary and cardiac functions or between low CPF and thoracic measurements.InterpretationOur results confirm the modest impact of pectus malformations on CPF at rest, without correlation with anamnestic dyspnoea on exertion, nor with chest pain or anatomical measurements. Validation of new correction indexes could be helping characterise these malformations and choose optimal therapeutic management.

The Effect of Using the Lower Limit of Normal 2.5 in Pulmonary Aeromedical Assessments

2020 ◽  
Vol 91 (8) ◽  
pp. 636-640 ◽  
Author(s):  
Yara Q. Wingelaar-Jagt ◽  
Thijs T. Wingelaar ◽  
Metin Bülbül ◽  
Pijke P. vd Bergh ◽  
Erik Frijters ◽  
...  
Keyword(s):  
Lower Limit ◽  
Reference Values ◽  
Pulmonary Function Tests ◽  
Fixed Ratio ◽  
Forced Expiratory Volume ◽  
Chi Squared ◽  
Group 2 ◽  
The Impact ◽  
Lower Limit Of Normal ◽  
Group 1

INTRODUCTION: Many regulations for aeromedical assessments state that a ratio between forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) of < 0.7 should be evaluated by a pulmonary specialist. The Global Lung Initiative (GLI) reference values introduced the lower limit of normal (LLN 2.5), in which the lowest 2.5% of the population is regarded as abnormal, instead of a fixed ratio. This study assesses the impact of adopting GLI reference values on aeromedical evaluation and referrals.METHODS: The Royal Netherlands Air Force performed 7492 aeromedical assessments between February 2012 and April 2017. Cases with FEV1/FVC < 0.7 from three groups were selected: 1) men < 25 yr; 2) men > 40 yr; and 3) women, with twice as many matched controls. Pearson's Chi-squared and Fisher’s exact tests were used to analyze the data.RESULTS: From the database, 23 (group 1), 62 (group 2), and 7 (group 3) cases were selected, with 184 controls. Respectively, 17%, 84%, and 29% would not be referred using the GLI. In the controls, this would lead to one additional referral (group 1). Qualitative analysis of the cases who would not be referred using the GLI showed that no significant diagnoses would have been missed.DISCUSSION: Using the GLI LLN 2.5 reference values for pulmonary function tests leads to significantly fewer referrals to a pulmonary specialist without missing relevant pulmonary pathology in our aircrew. This would reduce resources spent on the assessment of aircrew without compromising flight safety.Wingelaar-Jagt YQ, Wingelaar TT, Bülbül M, vd Bergh PP, Frijters E, Staudt E. The effect of using the lower limit of normal 2.5 in pulmonary aeromedical assessments. Aerosp Med Hum Perform. 2020; 91(8):636–640.

Factor XII Determinations in the Presence and Absence of Phospholipid Antibodies

1998 ◽  
Vol 79 (01) ◽  
pp. 87-90 ◽  
Author(s):  
D. W. Jones ◽  
M. Winter ◽  
M. J. Gallimore
Keyword(s):  
Lower Limit ◽  
Lupus Anticoagulant ◽  
Factor Xii ◽  
Chromogenic Substrate ◽  
Plasma Samples ◽  
Presence And Absence ◽  
Lower Limit Of Normal

SummaryFactor XII (FXII) levels were determined in plasma samples from 29 normal donors, 10 patients with inherited FXII deficiency (all lupus anticoagulant [LA] negative) and 67 LA positive patients, using clotting (FXIIct), chromogenic substrate (FXIIcs) and immunochemical (FXIIag) assays. Excellent correlations were obtained in the three FXII assays with the LA negative samples and between the FXIIcs and FXIIag assays in the LA positive samples. Correlations between both the FXIIcs and FXIIag with FXIIct in the LA positive patients were poor. Of 67 LA positive samples studied, 25 (37.3%) showed lower values in the FXIIct assay; 13 (19.4%) of these patients were pseudo FXII deficient with values of FXII below the lower limit of normal.These results indicate that a diagnosis of FXII deficiency can be made inappropriately in the presence of phospholipid antibodies and that such a diagnosis should not be made by FXIIct assay alone.

Agreement Between Fixed-Ratio and Lower Limit of Normal Spirometry Interpretation Protocols Decreases With Age

2013 ◽  
Vol 55 (7) ◽  
pp. 802-808 ◽  
Author(s):  
Marek A. Mikulski ◽  
Alicia K. Gerke ◽  
Spencer Lourens ◽  
Thomas Czeczok ◽  
Nancy L. Sprince ◽  
...  
Keyword(s):  
Lower Limit ◽  
Fixed Ratio ◽  
Lower Limit Of Normal

Evaluation of the Capillary Microhematocrit as a Screening Test for Anemia in Pediatric Office Practice

PEDIATRICS ◽  
1986 ◽  
Vol 78 (2) ◽  
pp. 206-209
Author(s):  
Paul C. Young ◽  
Barbara Hamill ◽  
Richard C. Wasserman ◽  
Joseph D. Dickerman
Keyword(s):  
Lower Limit ◽  
Screening Test ◽  
Pediatric Patients ◽  
Capillary Blood ◽  
White Children ◽  
Predictive Values ◽  
Special Skill ◽  
Capillary Sample ◽  
Sensitivity Specificity ◽  
Lower Limit Of Normal

The capillary microhematocrit test is widely used to screen pediatric patients for anemia. Recently, it has been suggested that this method produces spuriously elevated values compared with venous hematocrits measured by a Coulter electronic counter and might consequently fail to detect children who are truly anemic. To address this issue we studied 66 white children 9 months to 14 years of age whose capillary hematocrits were either below, equal to, or one or two points above the lower limit of normal for age. Venous specimens were obtained simultaneously with the capillary sample; hemoglobin, hematocrit, and mean corpuscular volume results were obtained using a Coulter electronic counter. Using published standards of venous hemoglobin, we determined the sensitivity, specificity, and predictive values of the capillary microhematocrit in this population of patients with low or borderline values. Twenty of the 66 patients had venous hemoglobin values less than the lower limit of normal. The sensitivity of the microhematocrit was 90.0%; the specificity was 43.5%. The predictive values for a normal (negative) hematocrit was 90.1%; the predictive value for a low (positive) hematocrit was 40.9%. We conclude that the microhematocrit method using capillary blood will miss very few patients with significantly low venous hemoglobin values and is thus an acceptable screening test for anemia. Because it does not require expensive equipment or special skill to obtain the specimen or perform the test, it is ideal for physicians' offices or nonhospital-based clinics.

scholarly journals The definition of anemia: what is the lower limit of normal of the blood hemoglobin concentration?

Blood ◽  
2006 ◽  
Vol 107 (5) ◽  
pp. 1747-1750 ◽  
Author(s):  
Ernest Beutler ◽  
Jill Waalen
Keyword(s):  
Normal Distribution ◽  
Lower Limit ◽  
Population Distribution ◽  
Hemoglobin Concentration ◽  
Blood Hemoglobin ◽  
Definition Of ◽  
Lower Limit Of Normal ◽  
Blood Hemoglobin Concentration

The diagnosis of anemia is an important aspect of the practice of hematology. The first step is to decide whether the patient is, in fact, anemic. Unless earlier blood counts are available, and they often are not, the physician must make his or her decision on the basis of the population distribution of hemoglobin values. How likely is it that the patient's hemoglobin value lies below the normal distribution; that is, “the lower limit”?

scholarly journals Global Lung Function Initiative 2012 reference equations for spirometry in the Norwegian population

2016 ◽  
Vol 48 (6) ◽  
pp. 1602-1611 ◽  
Author(s):  
Arnulf Langhammer ◽  
Ane Johannessen ◽  
Turid L. Holmen ◽  
Hasse Melbye ◽  
Sanja Stanojevic ◽  
...  
Keyword(s):  
Lung Function ◽  
Reference Values ◽  
Vital Capacity ◽  
Population Based ◽  
Forced Expiratory Volume ◽  
Female Adolescents ◽  
Norwegian Population ◽  
Reference Equations ◽  
Z Scores ◽  
Lower Limit Of Normal

We studied the fit of the Global Lung Function Initiative (GLI) all-age reference values to Norwegians, compared them with currently used references (European Community for Steel and Coal (ECSC) and Zapletal) and estimated the prevalence of obstructive lung disease.Spirometry data collected in 30 239 subjects (51.7% females) aged 12–90 years in three population-based studies were converted to z-scores.We studied healthy non-smokers comprising 2438 adults (57.4% females) aged 20–90 years and 8725 (47.7% female) adolescents aged 12–19 years. The GLI-2012 prediction equations fitted the Norwegian data satisfactorily. Median±sd z-scores were respectively 0.02±1.03, 0.01±1.04 and −0.04±0.91 for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC in males, and −0.01±1.02, 0.07±0.97 and −0.21±0.82 in females. The ECSC and Zapletal references significantly underestimated FEV1 and FVC. Stricter criteria of obstruction (FEV1/FVC <GLI-2012 lower limit of normal (LLN)) carried a substantially higher risk of obstructive characteristics than FEV1/FVC <0.7 and >GLI-2012 LLN. Corresponding comparison regarding myocardial infarction showed a four-fold higher risk for women.The GLI-2012 reference values fit the Norwegian data satisfactorily and are recommended for use in Norway. Correspondingly, the FEV1/FVC GLI-2012 LLN identifies higher risk of obstructive characteristics than FEV1/FVC <0.7.

Respiratory Symptoms Do Not Differ When Defining COPD By Fixed Ratio Or Lower Limit Of Normal

2010 ◽  
Author(s):  
Michael B. Drummond ◽  
David M. Shade ◽  
Cristine E. Berry ◽  
Meredith C. McCormack ◽  
Nadia N. Hansel ◽  
...  
Keyword(s):  
Lower Limit ◽  
Respiratory Symptoms ◽  
Fixed Ratio ◽  
Lower Limit Of Normal
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