Joint Indian Chest Society-National College of Chest Physicians (India) guidelines for spirometry.

Although a simple and useful pulmonary function test, spirometry remains underutilized in India. The Indian Chest Society and National College of Chest Physicians (India) jointly supported an expert group to provide recommendations for spirometry in India. Based on a scientific grading of available published evidence, as well as other international recommendations, we propose a consensus statement for planning, performing and interpreting spirometry in a systematic manner across all levels of healthcare in India. We stress the use of standard equipment, and the need for quality control, to optimize testing. Important technical requirements for patient selection, and proper conduct of the vital capacity maneuver, are outlined. A brief algorithm to interpret and report spirometric data using minimal and most important variables is presented. The use of statistically valid lower limits of normality during interpretation is emphasized, and a listing of Indian reference equations is provided for this purpose. Other important issues such as peak expiratory flow, bronchodilator reversibility testing, and technician training are also discussed. We hope that this document will improve use of spirometry in a standardized fashion across diverse settings in India.

Air pollution and environmental risk factors for altered lung function among adult women of an urban slum area of Delhi: A prevalence study.

BACKGROUND: Household and ambient air pollution are jointly responsible for about 7 million premature deaths annually. Women living in slums, with unhealthy environment, both indoors and outdoors, particularly those living close to industrial and/or vehicular pollution zones due to multiple sources of air pollution, are at the higher risk of having impaired lung function tests. OBJECTIVE: The aim of this study was to estimate the prevalence of abnormal lung functions and to identify the environmental risk factors associated with them among adult women of 18-59 years. MATERIALS AND METHODS: A total of 550 women aged 18-59 years were approached in a representative urban slum. Five hundred consented to participate and 299 had prebronchodilator spirometry satisfying ATS standards. House visits to assess environmental conditions were conducted to determine their association with forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). Chi-square test was used to test the association of risk factors with lung functions. ANOVA was used to test the association of mean values of FEV1 and FVC with age. RESULTS: Out of 299 participants with acceptable spirometric curves, 5% had reduced FEV1/FVC ratio than the normal and 26.8% and 17.4% had lower values than predicted for FVC and FEV1, respectively. Altered lung function was related to age, tobacco smoking, and history of respiratory disease. CONCLUSIONS: Both ambient and household air pollution have a deleterious pulmonary effect on long-term women residents of a representative urban slum in Delhi.

Impact of switching from Caucasian to Indian reference equations for spirometry interpretation.

BACKGROUND: In the absence of ethnically appropriate prediction equations, spirometry data in Indian subjects are often interpreted using equations for other ethnic populations. OBJECTIVES: To evaluate the impact of switching from Caucasian (National Health and Nutrition Examination Survey III [NHANES III] and Global Lung Function Initiative [GLI]) equations to the recently published North Indian equations on spirometric interpretation, and to examine the suitability of GLI-Mixed equations for this population. MATERIALS AND METHODS: Spirometry data on 12 323 North Indian patients were analysed using the North Indian equations as well as NHANES III, GLI-Caucasian and GLI-Mixed equations. Abnormalities and ventilatory patterns were categorised and agreement in interpretation was evaluated. RESULTS: The NHANES III and GLI-Caucasian equations and, to a lesser extent, the GLI-Mixed equations, predicted higher values and labelled more measurements as abnormal. In up to one third of the patients, these differed from Indian equations in the categorisation of ventilatory patterns, with more patients classified as having restrictive and mixed disease. CONCLUSION: The NHANES III and GLI-Caucasian equations substantially overdiagnose abnormalities and misclassify ventilatory patterns on spirometry in Indian patients. Such errors of interpretation, although less common with the GLI-Mixed equations, remain substantial and are clinically unacceptable. A switch to Indian equations will have a major impact on interpretation.

Prediction equations for spirometry in adults in western India.

BACKGROUND: Spirometry is an essential investigation in pulmonology. The predicted normal spirometry values depend on various physiological parameters. This study was conducted to collect updated information on pulmonary functions in normal adults from western India. MATERIAL AND METHODS: A prospective observational study was undertaken at a tertiary hospital in Mumbai enrolling healthy subjects, 18-75 years, with ethnic origin from western India. Spirometry measurements were carried out as per ATS/ERS-2005 guidelines using a non-heated Fleish Pneumotachograph spirometer. Data was analyzed using SPSS for Pearson's correlation analysis, multiple linear regressions and log transformations of variables to get the best prediction equations. RESULTS: 310 subjects (185 males, 125 females) were included. Lung function values were higher in men as compared to women. In multivariate linear regression models, age and height were major predictor variables for all spirometry parameters. Addition of weight as a determinant variable did not make significant contribution to the models except for PEFR in males and F75 in females. Regression equations were established for FVC, FEV1, FEV1/FVC ratio, PEFR, F25-75, F50, and F75. The standard-error-of-estimate was provided to enable computation of lower limits of normal for these parameters. CONCLUSION: We propose regression equations for spirometry variables developed using the current standards for adult West Indian population fulfilling the long-felt need for updated equations.

Interpretation of Spirometry: Selection of Predicted Values and Defining Abnormality.

Spirometry is the most frequently performed investigation to evaluate pulmonary function. It provides clinically useful information on the mechanical properties of the lung and the thoracic cage and aids in taking management-related decisions in a wide spectrum of diseases and disorders. Few measurements in medicine are so dependent on factors related to equipment, operator and the patient. Good spirometry requires quality assured measurements and a systematic approach to interpretation. Standard guidelines on the technical aspects of equipment and their calibration as well as the test procedure have been developed and revised from time-to-time. Strict compliance with standardisation guidelines ensures quality control. Interpretation of spirometry data is based only on two basic measurements--the forced vital capacity (FVC) and the forced expiratory volume in 1 second (FEV1) and their ratio, FEV1/FVC. A meaningful and clinically useful interpretation of the measured data requires a systematic approach and consideration of several important issues. Central to interpretation is the understanding of the development and application of prediction equations. Selection of prediction equations that are appropriate for the ethnic origin of the patient is vital to avoid erroneous interpretation. Defining abnormal values is a debatable but critical aspect of spirometry. A statistically valid definition of the lower limits of normal has been advocated as the better method over the more commonly used approach of defining abnormality as a fixed percentage of the predicted value. Spirometry rarely provides a specific diagnosis. Examination of the flow-volume curve and the measured data provides information to define patterns of ventilatory impairment. Spirometry must be interpreted in conjunction with clinical information including results of other investigations.

Guidelines for Diagnosis and Management of Bronchial Asthma: Joint Recommendations of National College of Chest Physicians (India) and Indian Chest Society.

Bronchial asthma is an important public health problem in India with significant morbidity. Several international guidelines for diagnosis and management of asthma are available, however there is a need for country-specific guidelines due to vast differences in availability and affordability of health-care facilities across the globe. The Indian Chest Society (ICS) and the National College of Chest Physicians (NCCP) of India have collaborated to develop evidence-based guidelines with an aim to assist physicians at all levels of health-care in diagnosis and management of asthma in a scientific manner. Besides a systematic review of the literature, Indian studies were specifically analysed to arrive at simple and practical recommendations. The evidence is presented under these five headings: (1) definitions, epidemiology and impact, (2) diagnosis, (3) pharmacologic management of stable disease, (4) management of acute exacerbations, and (5) non-pharmacologic management and special situations. The modified grade system was used for classifying the quality of evidence as 1, 2, 3, or usual practice point (UPP). The strength of recommendation was graded as A or B depending upon the level of evidence.

Prediction equations for spirometry in adults from northern India.

BACKGROUND: Most of the Indian studies on prediction equations for spirometry in adults are several decades old and may have lost their utility as these were carried out with equipment and standardisation protocols that have since changed. Their validity is further questionable as the lung health of the population is likely to have changed over time. OBJECTIVE: To develop prediction equations for spirometry in adults of north Indian origin using the 2005 American Thoracic Society/European Respiratory Society (ATS/ERS) recommendations on standardisation. METHODS: Normal healthy non-smoker subjects, both males and females, aged 18 years and above underwent spirometry using a non-heated Fleisch Pneumotach spirometer calibrated daily. The dataset was randomly divided into training (70%) and test (30%) sets and the former was used to develop the equations. These were validated on the test data set. Prediction equations were developed separately for males and females for forced vital capacity (FVC), forced expiratory volume in first second (FEV1), FEV1/FVC ratio, and instantaneous expiratory flow rates using multiple linear regression procedure with different transformations of dependent and/or independent variables to achieve the best-fitting models for the data. The equations were compared with the previous ones developed in the same population in the 1960s. RESULTS: In all, 685 (489 males, 196 females) subjects performed spirometry that was technically acceptable and repeatable. All the spirometry parameters were significantly higher among males except the FEV1/FVC ratio that was significantly higher in females. Overall, age had a negative relationship with the spirometry parameters while height was positively correlated with each, except for the FEV1/FVC ratio that was related only to age. Weight was included in the models for FVC, forced expiratory flow (FEF75) and FEV1/FVC ratio in males, but its contribution was very small. Standard errors of estimate were provided to enable calculation of the lower limits of normal and standardised residuals for these parameters. The equations were found to be valid on the test dataset, and therefore, may be extended to general population. Comparison with the 1960s equations revealed lack of good agreement, and substantially higher predicted FVC with the current equations, especially in the forty-years-plus age group, in both males and females. Even in the age group upto 40 years, the level of agreement was clinically not acceptable. CONCLUSIONS: Validated prediction equations have been developed for spirometry variables in adults of north Indian origin using the current ATS/ERS spirometry standardisation recommendations. The equations suggest an improvement in the lung health of the population over time in the middle-aged and the elderly. These equations should address a long-felt unmet need and enable a more appropriate evaluation of spirometry data in different chest diseases in Indian subjects.

Rapidly adapting receptor activity during oxidative stress induced airway hyperresponsiveness.

The responses of airway rapidly adapting receptors (RARs) to ovalbumin challenge and histamine were investigated in guinea pigs which were sensitized with ovalbumin. Sensitization alone increased the basal RAR activity. Antigen challenge stimulated them. Histamine doses which caused a 50% increase in airway resistance (ED50) were reduced immediately and 24h after antigen challenge indicating respectively early and late onset airway hyperresponsiveness. At these doses, there was a greater stimulation of the RARs compared to controls. An increase in lipid peroxidation and a decrease in glutathione peroxidase were observed also. With oral intake of vitamins C and E, attenuations in the basal RAR activity, the responses of RARs to antigen challenge and the oxidative stress were observed. With an increase in ED50, the RAR response to histamine became similar as in control. It is concluded that by decreasing the RAR responses to allergen and histamine, antioxidants may reduce reflex bronchoconstriction occurring in asthmatics.

Regression equations for spirometry in children aged 6 to 17 years in Delhi region.

BACKGROUND: Most of the studies carried out in India to develop regression equations for spirometry in children are now several years-to-decades old and had used equipment and measurement protocols that have since changed. Prediction equations using the current standardisation protocols for spirometry are not available. The lung health of the population may have changed too. OBJECTIVE: To develop regression equations for spirometry for children aged 6 to 17 years of north Indian origin in Delhi region. METHODS: School children of north Indian origin, as determined by mother tongue and parentage, aged 6 to 17 years were screened by a health questionnaire and physical examination and those found "normal" underwent spirometry according to the standardised procedure recommended by the American Thoracic Society/European Respiratory Society (ATS/ERS) task force in 2005. Pearson's correlation analysis was carried out to identify the predictor variables for spirometric parameters. Prediction equations were developed using the multiple linear regression procedure. The independent variables were entered in sequence of height, age and weight. R2, adjusted R2 and R2 change, standard errors of the estimate (SEE), and estimates of regression coefficients were obtained and the goodness of fit was examined. RESULTS: Data was obtained in 365 boys and 305 girls. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1) peak expiratory flow rate (PEFR), forced expiratory flow rate at 50% and 75% exhalation of vial capacity (F50 and F75) and mean forced expiratory flow rate over the middle 50% of the vital capacity (F25-75) showed moderate to strong correlations with age, height and weight in both boys and girls. In both genders, the equations explained very high variability of FVC, FEV1 and PEFR as shown by the R2 values. The explained variability for flow rates was lesser, with that for F75 being the least. CONCLUSIONS: Regression equations for spirometry variables for children of north Indian origin in Delhi region have been developed. These represent the first such effort from India after the publication of the ATS/ERS task force 2005 guidelines on standardisation of spirometry.

Combined pulmonary fibrosis and emphysema in a welder.

Combined pulmonary fibrosis and emphysema (CPFE) syndrome is an uncommon entity characterised by emphysema of the upper lobes and diffuse fibrosis of the lower lobes and carries a bad prognosis with the onset of pulmonary hypertension. Lung involvement due to exposures suffered by welders is generally considered benign though, rarely, a diffuse interstitial fibrotic disease has been reported. CPFE syndrome has however never been reported in welders. A 65-year-old man, welder by occupation and an ex-smoker, presented with progressive exertional dyspnoea associated with dry cough noticed for the last four months. On examination, there was mild tachypnea, clubbing and bilateral basal velcro crepitations on chest auscultation. Lung function test revealed mild mixed ventilatory impairment with severe diffusion defect. HRCT chest showed bilateral upper lobe emphysema and diffuse interstitial fibrosis in the lower lobes. Transbronchial lung biopsy revealed interstitial fibrosis, chronic inflammation and iron deposits. A diagnosis of combined pulmonary fibrosis with emphysema (CPFE) with interstitial pulmonary siderofibrosis (IPS) was established. A review of literature did not show any other report of a similar nature.

Quality of asthma management in an urban community in Delhi, India.

BACKGROUND & OBJECTIVES: High prevalence and poor control of asthma make its management a major public health issue worldwide, especially in developing countries. Optimum review of asthma management in the community is essential to improve asthma control. This study was conducted to investigate the quality of asthma management, knowledge about asthma and quality of life of asthma patients referred to a public tertiary care chest hospital in Delhi. METHODS: Diagnosis of asthma was confirmed by symptoms and reversible spirometry in 50 referred patients on their first visit. Patients were interviewed using three questionnaires on quality of asthma management before visiting referral hospital, asthma knowledge and asthma quality of life (AQLQ). Correlation amongst quality of treatment, asthma quality of life, and asthma knowledge was also determined. RESULTS: Findings revealed that only 60 per cent of patients were informed about their disease, and 10 per cent had undergone lung function tests previously. Only 44 per cent of patients were prescribed inhalers. None were provided with any educational material. Patients had poor knowledge of aetiology, pathophysiology, medication and how to assess the severity of their asthma. The mean scores in AQLQ indicated a moderate degree of impairment in quality of life. INTERPRETATIONS & CONCLUSIONS: This study provides evidence of unsatisfactory asthma management and patient-doctor interaction as patients had limited knowledge of asthma disease, its management and had poor quality of life as measured by a standardized questionnaire. Thus, there is need to implement suitable interventions to improve asthma management according to standard treatment guidelines in the community.

Effect of ozone on response to ovalbumin & its modulation by vitamins C & E in sensitized guinea pigs.

BACKGROUND & OBJECTIVES: Exposure to ozone and asthma are both associated with increased oxidative stress. Exposure to ozone therefore, may potentiate the airway response to allergens. We undertook this study to investigate the effect of ozone exposure on airway response to ovalbumin in sensitized guinea pigs and its modulation by dietary supplementation with antioxidant vitamins C and E. METHODS: After in vivo measurements of specific airways conductance (SGaw) and airway hyperresponsiveness (AHR) to inhaled histamine, guinea pigs were sensitized to ovalbumin and divided into three groups: (i) sensitized; (ii) sensitized and exposed daily to ozone; and (iii) sensitized, exposed daily to ozone and given dietary supplementation with vitamin C, 2 mg/kg body wt and E, 7 IU/kg body wt. A control group of nonsensitized animals was included. After 4 wk, AHR was measured again and animals were challenged with inhaled ovalbumin. Changes in SGaw were followed for early and late airway bronchoconstrictive responses. The following measurements were obtained: (i) parameters of oxidative stress--plasma malonaldehyde (MDA) as marker of lipid peroxidation and superoxide anion generation by leukocytes and bronchoalveolar lavage (BAL) cells; (ii) antioxidant status: red cell superoxide dismutase (SOD); and (iii) glutathione peroxidase (GPx). BAL cytology was studied. RESULTS: Ozone exposure resulted in an increase in AHR and early and late bronchoconstrictive responses after ovalbumin challenge, greater superoxide anion generation in BAL cells, higher plasma MDA levels and decrease in red cell SOD activity. Dietary supplementation with vitamin C and E prevented or ameliorated these responses. INTERPRETATION & CONCLUSIONS: Exposure to ozone at concentrations of 0.12 ppm for 2 h daily for 4 wk enhances the airway response to allergens in sensitized guinea pigs. Dietary supplementation with antioxidant vitamins E and C, affords variable degree of protection against this enhancement.

Evaluation of three scales of dyspnea in chronic obstructive pulmonary disease.

BACKGROUND: The Modified Medical Research Council (MMRC) scale, baseline dyspnea index (BDI) and the oxygen cost diagram (OCD) are widely used tools for evaluation of limitation of activities due to dyspnea in patients with chronic obstructive pulmonary disease (COPD). There is, however, limited information on how these relate with each other and with multiple parameters of physiological impairment. OBJECTIVES: To study the interrelationships between MMRC, BDI and OCD scales of dyspnea and their correlation with multiple measures of physiological impairment. MATERIALS AND METHODS: A retrospective analysis of pooled data of 88 male patients with COPD (GOLD stages II, III and IV) was carried out. Dyspnea was evaluated using the MMRC, BDI and OCD scales. Physiological impairment was assessed by spirometry (FVC % predicted and FEV1 % predicted), arterial blood gas (ABG) analysis and measurement of the 6-min walk distance (6MWD). RESULTS: The interrelationships between MMRC, BDI and OCD scales were moderately strong. The BDI and OCD scores had strong correlations with ABG abnormalities, weak correlations with spirometric parameters but none with 6MWD. MMRC grades were significantly associated with BDI and OCD scores but did not show clear associations with spirometric parameters, ABG abnormalities and 6MWD. CONCLUSIONS: The MMRC grades of dyspnea and the BDI and OCD scales are moderately interrelated. While the BDI and OCD scales have significant associations with parameters of physiological impairment, the MMRC scale does not.

Assessment of control in asthma: the new focus in management.

Several evidence-based guidelines on the management of asthma have been developed in the last two decades. There is a consensus that a stepped-up approach with anti-inflammatory drugs based on severity forms the cornerstone of treatment. Goals of management have been defined. Studies in several countries have however shown that a large majority of patients have failed to attain the goals of treatment. This has led to a reconsideration of strategy of management. The focus is now shifting to an assessment and a treatment approach based on control. The objective is to achieve and monitor to maintain control. The previous treatment algorithms based on assessment of severity are being discarded. It has been emphasised that the state of control is a dynamic one and therefore a regular assessment and modifications of treatment according to changes in its level are necessary. There is a need to use some method to assess control. A wide range of techniques to assess control are available that can be used depending on the requirements, settings and resources. Assessment of control may be an informal global judgement by the physician or simple tools may be used. Several formal instruments to assess the state of control have also been developed and validated in different settings. These allow a more objective and a quantitative evaluation. Control needs to be assessed at every visit of a patient and treatment adjusted accordingly.

Effect of vitamin E supplementation with standard treatment on oxidant-antioxidant status in chronic obstructive pulmonary disease.

BACKGROUND & OBJECTIVES: Chronic oxidant burden and depletion of endogenous antioxidants have been proposed to play a key role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Exogenous antioxidants have potential therapeutic implications and their role has not been explored in COPD. The objective of this study was to investigate the effect of supplementation of standard treatment (inhaled long-acting beta(2) agonists, anticholinergics and corticosteroids) with vitamin E on oxidant-antioxidant balance in patients with COPD. METHODS: The study was carried out in the outpatient setting. Patients were divided into two groups: group A- placebo group (n=14), receiving only standard therapy, and group B- vitamin E-supplemented group (n=10), receiving 400 IU of vitamin E capsules twice daily in addition to standard therapy. Spirometry and clinical assessment were carried out at the start and completion of 8 wk treatment along with measurements of several biochemical parameters of oxidant-antioxidant status in plasma, leukocytes and red cells separated from venous blood. RESULTS: Leukocyte superoxide generation was decreased in both the groups. Vitamin E-supplemented group had significantly increased levels of plasma sulphydryls and red cell catalase while the placebo group had decreased levels of plasma nitrates and nitrites. No significant differences were observed in red cell superoxide dismutase and glutathione peroxidase activities, total blood glutathione, and plasma total antioxidant capacity, lipid peroxides and glutathione peroxidase activity in either group. There was a similar degree of lung function and clinical improvement in both the groups. INTERPRETATION & CONCLUSION: Our findings showed that an 8 wk supplementation of standard treatment with 400 IU twice daily of vitamin E did not provide any additional clinical benefit although it augmented certain endogenous antioxidants in patients with COPD.

Using arm span to derive height: impact of three estimates of height on interpretation of spirometry.

BACKGROUND: When standing height required to calculate forced vital capacity (FVC) cannot be measured, it can be derived from arm span using different methods. OBJECTIVES: To compare three different estimates of height derived from arm span and investigate their impact on interpretation of spirometric data. METHODS: In a cross-sectional study, 517 subjects aged 7 to 76 years, with various respiratory diseases underwent spirometry. Three estimates of height were obtained from arm span: (a) by direct substitution (Ht(AS)); (b) estimated height (Ht(est)), obtained from the mean arm span:standing height ratio; and (c) predicted height (Ht(pred)), obtained from arm span by linear regression analysis. Predicted values of forced vital capacity (FVC) obtained from these estimates were compared with those obtained from actual standing height (Ht(act)), followed by Bland Altman analysis of agreement in the patterns of ventilatory impairment. RESULTS: The arm span was 5%-6% greater than the height. The difference increased with increasing height. Ht(AS) and the FVC predicted from it were significantly greater than the other measures of height and the related predicted FVCs respectively. Compared to Ht(act), Ht(AS) gave a misclassification rate of 23.7% in taller subjects (Ht(act) > 150 cm) and 14.2% in shorter subjects in the patterns of ventilatory impairment. Misclassification rates were 6%-8% with Ht(est) and Ht(pred). Agreement analysis showed that FVCs predicted from Ht(pred) had the best agreement with the FVC predicted from Ht(act). CONCLUSIONS: Among several methods of estimating height from the arm span, prediction by regression is most appropriate as it gives least errors in interpretation of spirometric data.