Diagnosis Of Airway Obstruction Research Articles

High-accuracy detection of airway obstruction in asthma using machine learning algorithms and forced oscillation measurements

Background and ObjectivesThe main pathologic feature of asthma is episodic airway obstruction. This is usually detected by spirometry and body plethysmography. These tests, however, require a high degree of collaboration and maximal effort on the part of the patient. There is agreement in the literature that there is a demand of research into new technologies to improve non-invasive testing of lung function. The purpose of this study was to develop automatic classifiers to simplify the clinical use and to increase the accuracy of the forced oscillation technique (FOT) in the diagnosis of airway obstruction in patients with asthma. MethodsThe data consisted of FOT parameters obtained from 75 volunteers (39 with obstruction and 36 without). Different supervised machine learning (ML) techniques were investigated, including k-nearest neighbors (KNN), random forest (RF), AdaBoost with decision trees (ADAB) and feature-based dissimilarity space classifier (FDSC). ResultsThe first part of this study showed that the best FOT parameter was the resonance frequency (AUC = 0.81), which indicates moderate accuracy (0.70–0.90). In the second part of this study, the use of the cited ML techniques was investigated. All the classifiers improved the diagnostic accuracy. Notably, ADAB and KNN were very close to achieving high accuracy (AUC = 0.88 and 0.89, respectively). Experiments including the cross products of the FOT parameters showed that all the classifiers improved the diagnosis accuracy and KNN was able to reach a higher accuracy range (AUC = 0.91). ConclusionsMachine learning classifiers can help in the diagnosis of airway obstruction in asthma patients, and they can assist clinicians in airway obstruction identification.

Sequential use of cryoextraction postelectrocautery for airway recanalization using fiberoptic bronchoscopy

Airway obstruction presents with dyspnea, cough, hemoptysis, and atelectasis. Removing or decreasing the size of the obstructing lesions improves patient’s symptoms and life quality. Assessing the efficacy and safety of sequential use of cryoextraction and electrocautery in achievement of airway patency using fiberoptic bronchoscopy (FOB). This study was conducted at the Chest Medicine Department, Mansoura University, Egypt and included 22 patients with central airway obstruction (15 males and seven females) with a mean age of 50.5 ± 18.3 years. After etiologic diagnosis of airway obstruction, they were divided into two groups: group A (nonmalignant); eight patients and group B (malignant); 14 patients. All patients were subjected to sequential use of cryoextraction after electrocautery. Operable, unfit patients or patients with extraluminal obstruction were excluded. Clinical, radiological, functional, and bronchoscopic data were evaluated before and after FOB. The improvement in performance scale was highly significant in group B (P < 0.001) and significant in group A (P = 0.001). Spirometric parameters improved in both groups but were highly significant in group B (P < 0.001). Radiological improvement occurred in four out of eight of group A and in three out of 14 of group B. FOB score improved in group B (P = 0.003) and was more significant in group A. The procedure was complicated with atrial fibrillation and hemoptysis in one case and postbronchoscopy hypoxemia in two cases with no deaths. Cryoextraction after electrocautery using FOB are effective, safe, easy, and cheap in achieving airway patency. Egypt J Broncho 2015 9:269–275

Airways resistance and specific conductance for the diagnosis of obstructive airways diseases.

BackgroundAirway resistance (RAW) and specific airway conductance (sGAW) are measures that reflect the patency of airways. Little is known of the variability of these measures between different lung diseases. This study investigated the contribution of RAW and sGAW to a diagnosis of obstructive airways disease and their role in differentiating asthma from COPD.Methods976 subjects admitted for the first time to a pulmonary practice in Belgium were included. Clinical diagnoses were based on complete pulmonary function tests and supported by investigations of physicians’ discretion. 651 subjects had a final diagnosis of obstructive diseases, 168 had another respiratory disease and 157 subjects had no respiratory disease (healthy controls).ResultsRAW and sGAW were significantly different (p < 0.0001) between obstructive and other groups. Abnormal RAW and sGAW were found in 39 % and 18 % of the population, respectively, in which 81 % and 90 % had diagnosed airway obstruction. Multiple regression revealed sGAW to be a significant and independent predictor of an obstructive disorder. To differentiate asthma from COPD, RAW was found to be more relevant and statistically significant. In asthma patients with normal FEV1/FVC ratio, both RAW and sGAW were more specific than sensitive diagnostic tests in differentiating asthma from healthy subjects.ConclusionsRAW and sGAW are significant factors that contribute to the diagnosis and differentiation of obstructive airways diseases.

Ultrasound Analysis of Diaphragm Kinetics and the Diagnosis of Airway Obstruction: The Role of the M-Mode Index of Obstruction

Diaphragm motion in forced expiration can be analyzed using M-mode ultrasound in an anterior subcostal approach. Maximum expiratory diaphragmatic excursion (EDEMax) and forced expiratory diaphragmatic excursion in the first second (FEDE1) are considered the physiopathological analogues of vital capacity (VC) and forced expiratory volume in the first second (FEV1). As the FEV1/VC % ratio is used as a marker of obstruction, our aim was to determine if the ratio FEDE1/EDEMax (M-mode index of obstruction [MIO]) differs between healthy subjects and patients with airway obstruction. One hundred twenty-four outpatients were examined by diaphragm ultrasound after spirometry. The MIO, expressed as the mean ± standard deviation (range), was 87.08 ± 6.64 (72.84–100) in the healthy group (N = 61) and 67.09 ± 12.49 (33.33–91.30) in the group with obstructed airways (N = 63). The difference between the two groups was significant (p < 0.0001), and MIO was significantly correlated with FEV1/VC (p < 0.0001). A MIO <77 was identified as a possibile cutoff for suspecting an obstructive spirometric pattern with a 95.5% positive predictive value. The MIO can be interpreted as a speed index of diaphragmatic relaxation that seems to be slower in obstructed patients and could be used to screen for obstructed airway diseases.

Fixed Cut-Off for FEV1/FEV6 and FEV6 in Detection of Obstructive and Restrictive Patterns

BackgroundChronic obstructive pulmonary diseases (COPD) have been defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as irreversible conditions which are diagnosed by fixed cut-off points of FEV1/FVC.ObjectiveThe aim of this study was to determine the cut-off points for FEV1/FEV6 ratio and FEV6 as alternatives for FEV1/FVC and FVC in detection of airway obstruction and lung restriction, respectively.Materials and MethodsA total of 318 Spiro metric examinations of subjects referred to Shariati hospital were analyzed. A subject was considered to have obstruction if FEV1/FVC was lower than 70%. The restriction was defined as FVC < 80% in the absence of obstruction. The Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FEV1/FEV6 and FEV6 were calculated.ResultsThis study shows that the current cut-off points used to detect obstruction and restriction can be replaced by FEV1/FEV6 < 71% and FEV6 < 83%, respectively. FEV1/FEV6 had sensitivity of 95.5% and specificity of 99.4%; the PPV and NPVs were 99.3% and 96.3%. The prevalence of obstruction was 49.4%. For restrictive pattern, FEV6 had sensitivity of 93%, specificity of 79.5% with PPV of 18% and NPV of 99.5%. The prevalence of restriction was 6.3%.ConclusionsThe FEV1/FEV6 ratio can be used as a valid surrogate for FEV1/FVC in the diagnosis of airway obstruction, especially for screening purposes in high-risk populations for COPD. Moreover, FEV6 is an acceptable alternative for FVC in detection of restrictive pattern.

Lung function evaluation: comparing fixed percentage reference values vs. the 5th percentile in the diagnosis of airway obstruction

Lung function evaluation: comparing fixed percentage reference values vs. the 5th percentile in the diagnosis of airway obstruction

FEV1/FEV6: A Reliable, Easy-to-Use, and Cheaper Alternative to FEV1/FVC in Diagnosing Airway Obstruction in Indian Population

Background. FEV1/FEV6 has been proposed as a cheap, reproducible and valid alternative to FEV1/FVC in spirometry. No Indian data exists on its utility to diagnose airway obstruction. Aim. we sought to determine a fixed cut off of FEV1/FEV6 to diagnose obstruction corresponding to FEV1/FVC &lt; 0.70 proposed by GOLD guidelines. Method. Spirometry was done on patient referred to a tertiary centre in India. Age, sex, height weight were recorded in addition to spirometric variables like FEV1, FVC, FEV6. The sensitivity, specificity, positive and negative predictive values of FEV1/FEV6 were determined with respect to gold standard of FEV1/FVC &lt; 0.70. Results. 467 spirometries were analysed after meeting the ATS acceptability criteria. Considering FEV1/FVC &lt; 0.7 as being the gold standard for obstruction, ROC curve was used to determine the best corresponding cut-off for FEV1/FEV6. The area under the curve was 99.3% (95% CI: 98.1–99.8%), and the FEV1/FEV6 cut-off, corresponding to the greatest sum of sensitivity and specificity, was 73%. For the total population, the FEV1/FEV6 sensitivity, specificity, PPV, NPV were was 95.7 %, 94.2 %, 87.5 % and 97.9 % respectively. Agreement by Kappa value between two cut offs was excellent 0.89 (0.87–0.91). Conclusion. FEV1/FEV6 &lt; 73% is a new reliable spirometry index to diagnose airway obstruction in Indian population.

Diagnosis of airway obstruction in the elderly: contribution of the SARA study.

BackgroundThe choice between lower limit of normal or fixed value of forced expiratory volume in one second/forced vital capacity ratio (FEV1/FVC) < 0.70 as the criterion for confirming airway obstruction is an open issue. In this study, we compared the criteria of lower limit of normal and fixed FEV1/FVC for diagnosis of airway obstruction, with a focus on healthy elderly people.MethodsWe selected 367 healthy nonsmoking subjects aged 65–93 years from 1971 participants in the population-based SARA (Salute Respiratoria nell’Anziano, Italian for “Respiratory Health in the Elderly”) study, analyzed their spirometric data, and tested the relationship between spirometric indices and anthropometric variables. The lower limit of normal for FEV1/FVC was calculated as the fifth percentile of the normal distribution for selected subjects.ResultsWhile FEV1 and FVC decreased significantly with aging, the relationship between FEV1/FVC and age was not statistically significant in men or women. The lower limit of normal for FEV1/FVC was 0.65 in men and 0.67 in women. Fifty-five participants (15%) had FEV1/FVC < 0.70 and would have been inappropriately classified as obstructed according to the Global Initiative for Obstructive Lung Disease, American Thoracic Society/European Respiratory Society, and Canadian guidelines on chronic obstructive pulmonary disease. By applying different FEV1/FVC thresholds for the different age groups, as previously proposed in the literature, (0.70 for <70 years, 0.65 for 70–80 years, and 0.60 for >80 years) the percentage of patients classified as obstructed decreased to 6%. No subjects older than 80 years had an FEV1/FVC < 0.60.ConclusionThe present results confirm the inadequacy of FEV1/FVC < 0.70 as a diagnostic criterion for airway obstruction after the age of 65 years. FEV1/FVC < 0.65 and <0.67 (for men and women, respectively) could identify subjects with airway obstruction in such a population. Further reduction of the threshold after 80 years is not justified.

GOLD and the fixed ratio

GOLD and the fixed ratio J&oslash;rgen VestboUniversity of Manchester, Manchester, UKI read with interest the paper entitled &quot;Diagnosis of airway obstruction in the elderly: contribution of the SARA study&quot; by Sorino et al in a recent issue of this journal.1 Being involved in the Global Initiative for Obstructive Lung Diseases (GOLD), it is nice to see the interest sparked by the GOLD strategy document. However, in the paper by Sorino et al, there are a few misunderstandings around GOLD and the fixed ratio (forced expiratory volume in 1 second/forced volume vital capacity&nbsp;&lt; 0.70) that need clarification.View original paper by Sorino and colleagues.

Comparison of the Lower Confidence Limit to the Fixed-Percentage Method for Assessing Airway Obstruction in Routine Clinical Practice

Although the statistically derived lower limit of normal (LLN) for the ratio of FEV(1) to FVC is considered superior to a fixed cutoff value (such as 0.70) for diagnosing airway obstruction, the fixed-cutoff method continues to be used and advocated. To evaluate the misclassification of spirometrically determined airway obstruction arising from the use of the fixed-percent method, in comparison to the LLN method for FEV(1)/FVC. We reviewed 27,307 spirometry records from adult men, and diagnosed airway obstruction based on the LLN (predicted value minus 1.645 times the standard error of estimate from a north Indian reference equation for FEV(1)/FVC) and based on a fixed cutoff of 0.70. We computed agreement and discordance between the two methods, and determined the sensitivity, specificity, and predictive values of the fixed-percent method in identifying true obstruction. The results were discordant in 1,622 subjects (6%). Overall agreement between the two methods was good (kappa estimate 0.869), but worsened considerably with advancing age. 1,290 subjects (5%) who were deemed normal with the LLN method were diagnosed as having airway obstruction with the fixed-percentage method. Overall the sensitivity, specificity, and positive predictive value of the fixed-percentage method were 0.963, 0.929, and 0.871, respectively. Specificity and positive predictive value decreased sharply with advancing age. The negative age-dependence of FEV(1)/FVC results in over-diagnosis of airway obstruction in middle-aged and elderly men, and under-diagnosis in young men, with the fixed-percentage method. Airway obstruction should be assessed with the LLN of FEV(1)/FVC, with the LLN derived from appropriate reference equations.

Accuracy of FEV1/FEV6 in Detecting Airway Obstruction and Factors Affecting Its Performance: A Metaanalysis

PURPOSE: Background: FEV1/FEV6 has been proposed as a diagnostic test to measure airway obstruction as an alternative to FEV1/FVC; due to ease of use and performance. Many studies have been conducted for investigating usefulness of FEV1/FEV6. However there is paucity of systematic reviews and meta-analyses. Purpose: To conduct a meta-analysis evaluate, in adults, diagnostic accuracy of FEV1/FEV6 for diagnosing airway obstruction.

Management of Foreign Bodies Obstructing the Airway in Children

To review national trends in the management of pediatric airway foreign bodies (A-FBs) and esophageal foreign bodies (E-FBs) that obstruct the airway. Retrospective review using a national pediatric data set (Kids' Inpatient Database). Pediatric patients admitted across the United States during 2003. The Kids' Inpatient Database 2003 samples 2 984 129 pediatric discharges from 3438 hospitals in 36 states. The Kids' Inpatient Database 2003 was analyzed for A-FBs and E-FBs (International Classification of Diseases, Ninth Revision, Clinical Modification codes E911 and E912) in patients 20 years or younger, and weighted data are presented to facilitate national estimates. A total of 2771 patients (59% male) were admitted for an A-FB or an E-FB that was obstructing the airway. The mean (SE) age of the patients was 3.5 (0.17) years; 55% were younger than 2 years. The foreign bodies were classified as food (42%; mean age, 2.5 years) or other (58%; mean age, 4.3 years). The average length of stay was 6.4 days (median [SE], 1.5 [0.6] days), and the average number of procedures was 2.4 (median [SE], 1.3 [0.1] procedures). Seventy-one percent of the patients were treated at teaching hospitals. The mean (SD) total charges were $34 652 ($3543), with regional variation (P < .001). Children's hospitals (28%) had higher mean total charges than nonchildren's hospitals (P = .03); 3.4% of admissions died in the hospital (mean [SE] age, 4.6 [0.9] years), with an average length of stay of 11.7 (SE, 2.7) days and an average of 6.2 (SE, 0.7) procedures. Bronchoscopy (52%), esophagoscopy (28%), and tracheotomy (1.7%) were the primary procedures performed. The rates of positive FB findings for bronchoscopy and esophagoscopy were 37% and 46%, respectively. Pediatric A-FBs and E-FBs that obstruct the airway occur infrequently. Most of the patients are referred to teaching institutions. Among patients who were admitted with a diagnosis of airway obstruction from an A-FB or an E-FB, the rates of positive findings at surgery were 37% and 46%, respectively. A surprisingly high mortality rate was noted. Alternative education measures should be considered to train physicians in the management of this infrequent, potentially lethal condition.

FEV 6 as screening tool in spirometric diagnosis of obstructive airway disease

Context:The use of spirometry is currently limited to the diagnosis of obstructive airway disease for tertiary centers mainly because of the unmet need for technical expertise and funding. Use in primary care asks for a simpler and cost-effective screening tool for obstructive airway disease.Aim:To estimate the efficacy of FEV6 against the current standard of FVC in the spirometric diagnosis of obstructive airway disease.Setting and Design:The Pulmonary Function Laboratory of a tertiary care hospital in Coastal South India. It was a descriptive study.Materials and Methods:We analyzed 150 serial patients on ATS standardized spirometers. The patients were classified into normal subjects and those with airway obstruction, further categorized as mild, moderate and severe and those with mixed defect. Those with obstruction were also classified as having reversible and irreversible defects.Statistical Analysis:Data was analyzed using SPSS Software (v.11.5), statistical test ANOVA and Pearson correlation was done and P less than 0.05 considered statistically significant.Results:FVC and FEV6 showed a linear correlation in all subjects. The difference in means was statistically significant in all subjects. The sensitivity and specificity of FEV1/FEV6 in comparison to FEV1/FVC were both found to be 100%.Conclusion:FEV6 is an excellent screening tool in the diagnosis of airway obstruction but, there is a necessity for further research to confirm our findings. There is also a need for reference values in an Indian setting to find out the efficiency of this new parameter. Our sample size is relatively small and comprises of a very high proportion (70%) of subjects with airway obstruction and so our results may not be applicable for use in general population.

Diagnosis of Airway Obstruction or Restrictive Spirometric Patterns by Multiclass Support Vector Machines

This paper presents the use of multiclass support vector machines (SVMs) for diagnosis of spirometric patterns (normal, restrictive, obstructive). The SVM decisions were fused using the error correcting output codes (ECOC). The multiclass SVM with the ECOC was trained on three spirometric parameters (forced expiratory volume in 1s--FEV1, forced vital capacity--FVC and FEV1/FVC ratio). The total classification accuracy of the SVM is 97.32%. The obtained results confirmed the validity of the SVMs to help in clinical decision-making.

Should FEV 1 /FEV 6 Replace FEV 1 /FVC Ratio To Detect Airway Obstruction?

The conventional FEV(1)/FVC test is the "gold standard" to quantitate airway obstruction, but elderly subjects or patients with severe respiratory diseases quite frequently cannot make such an effort. Many studies have investigated the usefulness of FEV(1)/forced expired volume in 6 s (FEV(6)) measurements as an alternative for FEV(1)/FVC for diagnosis of airway obstruction. We conducted a meta-analysis to determine the FEV(1)/FEV(6) substitute for FEV(1)/FVC in the diagnosis of airway obstruction. After a systematic review of all-language studies, sensitivity, specificity, and other measures of accuracy of FEV(1)/FEV(6) in the diagnosis of airway obstruction were pooled using random-effects models. Summary receiver operating characteristic curves were used to summarize overall test performance. Eleven studies met our inclusion criteria. The summary estimates for FEV(1)/FEV(6) in the diagnosis of airway obstruction in the studies included were as follows: sensitivity, 0.89 (95% confidence interval [CI], 0.83 to 0.93); specificity, 0.98 (95% CI, 0.95 to 0.99); positive likelihood ratio, 45.46 (95% CI, 18.26 to 113.21); negative likelihood ratio, 0.11 (95% CI, 0.08 to 0.17); diagnostic odds ratio, 396.02 (95% CI, 167.32 to 937.31); and diagnostic score, 5.98 (95% CI, 5.12 to 6.84). FEV(1)/FEV(6) is a sensitive and specific test for the diagnosis of airway obstruction. FEV(1)/FEV(6) can be used as a valid alternative for FEV(1)/FVC in the diagnosis of airway obstruction.

Is Tidal Breathing Analysis Useful for Diagnosis of Airway Obstruction in Children?

Is Tidal Breathing Analysis Useful for Diagnosis of Airway Obstruction in Children?

How appropriate is the gold standard for diagnosis of airway obstruction?

How appropriate is the gold standard for diagnosis of airway obstruction?

FEV1/FEV6 VS FEV1/FVC IN THE SPIROMETRIC DIAGNOSIS OF AIRWAYS OBSTRUCTION AMONG ASIANS

PURPOSE: Forced expiratory volume in six seconds (FEV6) is an acceptable alternative to forced vital capacity (FVC) for diagnosing airways obstruction in adults. The acceptability criteria for forced vital capacity (FVC) maneuver during pulmonary function tests is that duration of exhalation should be at least 6 seconds, during which a minimum 1 second plateau could be reached. This total duration may be as long as 15-20 seconds in cases with airways obstruction. The use of FEV6 simplifies testing procedures, reduces test variability, and may improve accuracy in diagnosing airway obstruction.

Determinação da eficiência do VEF6 como substituto da CVF na triagem diagnóstica da doença pulmonar obstrutiva crônica através da comparação entre as relações VEF1/CVF e VEF1/VEF6

To determine the efficacy of using forced expiratory volume in six seconds (FEV6) as a surrogate for forced vital capacity (FVC) in the diagnostic screening for chronic obstructive pulmonary disease (COPD) by comparing FEV1/FVC ratios with FEV1/FEV6 ratios. In November of 2003, on World COPD Day, we conducted a campaign of diagnostic screening for COPD. The participants completed the clinical questionnaire of the Global Initiative for Obstructive Lung Disease, and those who responded affirmatively to at least three questions underwent spirometry. A total of 134 individuals responded to three questions affirmatively and underwent spirometry. Of those, 59 were excluded: 45 for being non-smokers and 14 due to the fact that their tests did not meet the American Thoracic Society criteria for satisfactory spirometry. The number of tests in which the FEV1/FEV6 ratio was below 70% was similar to that found for the FEV1/FVC ratio. The sensitivity of FEV1/FEV6 in diagnosing airway obstruction (defined as FEV1/FVC below 70%) was 92%, and its specificity was 99%. The positive predictive value was 100%, and the negative predictive value was 98%. The Kendall correlation test revealed r = 0.99 (p < 0.0001). The t-test for paired samples revealed a negative correlation: t = -5.93 (p < 0.0001). The FEV1/FEV6 proved efficient for use in the diagnostic screening for COPD. There is a strong correlation between FEV1/FVC and FEV1/FEV6.

Forced oscillation technique

FOT may hold the promise of improving the diagnosis of airway obstruction, but may be even better in quantifying the magnitude of airway reversibility and hyper-reactivity, helping in the adjustment of therapy, and monitoring disease progression in young children.