The Department of Cardiorespiratory Physiology was started by Prof AS Paintal in 1954. At the initiative of the visiting surgical team from Norway, a lung function laboratory was set up to help on the assessment of patients undergoing thoracic surgery at the Silver Jubilee Tuberculosis Hospital (now called Rajan Babu Tuberculosis Hospital) to judge their suitability for the proposed intervention. The Department offered facilities for measurements of vital capacity and oxygen uptake by spirometry and bronchospirometry , managed by Dr MS Chowdhry, Junior Research Officer and Dr SK Jain, Research Fellow.

In 1955, Dr RL Riley, Professor of Environmental Medicine at the John Hopkins Institute, USA, visited the Institute under the USA Technical Cooperation Mission plan of the Government of India. He helped the Department in upgrading the lung function testing facilities by adding tests of blood gas analysis and lung mechanics. Subsequently, facilities for cardiac cathetarization were provided for study of pulmonary haemodynamics in 1959. An Asthma Research Cell was started in 1977 in collaboration with the Institute of Nuclear Medicine and Allied Sciences (INMAS) headed by Dr KP Agrawal, Scientist at INMAS. He later joined the Department as Reader on deputation. The cell has carried out pioneering work in understanding the biochemical basis of bronchial asthma and in development of body plethysmographic techniques for measuring airways conductance in humans and animal models. This work was carried further by Dr SK Chhabra who joined as Lecturer in 1988. Prof MB Dikshit joined briefly from 1993 to 1995 in the Department.

The Department was the first in the country to establish comprehensive facilities for investigating lung function and pulmonary haemodynamics in pulmonary diseases. It continues to provide high quality services in these areas for patients and for research. Research into various aspects of bronchial asthma (including epidemiology, pathophysiology, biochemical abnormalities and therapeutics and development of animal models) and lung function tests continue to be the thrust areas for the Department. The Department is one of the constituent units of the Clinical Research Centre of the Institute and runs a clinical unit for providing patient management services, both outdoor and indoors.

Major Activities and Achievements

Research

1. Aerodynamics of chronic pulmonary diseases.

2. The mechanisms of high altitude pulmonary oedema in man and experimental models.

3. Vagal control of breathing in health and disease.

4. Study of long-term pulmonary toxicity in Bhopal Gas victims exposed to "toxic gas"

5. Standardization of new technique for producing surface anesthesia of vagal sensory receptors in man and experimental animals.

6. Indigenous drugs trial in bronchial asthma

A multicentric double-blinded placebo-controlled trial of several indigenous drugs was carried out by the ICMR between 1986 to 1991. The Department was one of the centres and carried out the study on Albizzia Lebbeck. The drug was not found to offer any advantage over salbutamol.

7. Establishing lung function and exercise responses- norms in Indians.

Review of regression equations of various lung function parameters and development of new equations are continuous programmes of the Department. Data on normal subjects is collected on a regular basis for this purpose. The Department developed regression equations for north Indians in the sixties and these are still useful. New equations have been developed recently.

8. Study of variability of flow volume parameters in asthmatics and normal individuals .

The reproducibility of spirometric parameters on repeat testing was evaluated in asthmatics and normals. While FVC and FEV 1 had excellent reproducibility, flow rates had upto 25% variability and it was greater among asthmatics..

9. Effect of prednisolone on deep inspiration-induced bronchoconstriction in asthmatics

Deep inspiration induces a bronchospastic response especially in patients with severe airways obstruction. Treatment with oral prednisolone abolishes this response suggesting that it is related to the degree of airways Inflammation.

10. Clinico-physiological relationships in diffuse interstitial lung diseases

Studies on diffuse interstitial lung diseases showed that there was no significant correlation between FVC, reduction in transfer factor and the degree of hypoxaemia.

11. Studies on techniques of aerosol delivery

Delivery of aerosol from a metered-dose inhaler was found to be similar with closed-mouth and open-mouth techniques.

12. Studies on the role of corticosteroids in nocturnal asthma

The role of inhaled and oral corticosteroids in the management of nocturnal asthma was studied. Beclomethasone dipropionate was found to be very effective in controlling nocturnal symptoms of asthma when used on a regular basis. Prednisolone was found to be superior to sustained-release theophylline fin providing quick control of nocturnal symptoms.

13. Studies on aetiologic significance of different fungal, pollen and insect allergens

In collaboration with the Department of Respiratory Allergy and Applied Immunology the aetiological role of different airborne allergens in asthma was explored.

14. Response to exercise in asthmatics and modulation of airway response to exercise in asthmatics by two different doses of disodium cromoglycate

Definite occurrence of a late phase bronchospasm was documented following the well-known early bronchospasm. Contrary to the generally held belief, a definite dose-related response inhibition was observed with disodium cromoglycate. Higher dose was effective in patients not responding to the lower doses of the drug.

15. Anti-inflammatory versus combined anti-inflammatory and bronchodilator therapy in asthma

It has been suggested recently that anti-inflammatory therapy with inhaled steroids is superior to combined anti-inflammatory and bronchodilator therapy. A study was started to compare the two approaches to treatment. It was observed that regular bronchodilator therapy in combination with inhaled steroids did not give better results compared to as-needed bronchodilator therapy in combination with inhaled steroids.

16. Epidemiological investigation into nocturnal asthma

The clinical and physiological characteristics of patients having nocturnal asthma were studied. These patients were found to have a more severe disease as compared to those not having nocturnal asthma.

17. Effect of prednisolone on in-vivo airway smooth muscle response to salbutamol and histamine

There is insufficient information on how prednisolone, a very effective drug for bronchial asthma modulates airway smooth muscle response to bronchodilator and bronchoconstrictor agents. This study has been started recently.

18. Growth and development of lung function

The growth and development of lung function from childhood through adolescence to childhood is being studied. The role of socioeconomic factors, nutritional and environmental factors will be investigated.

19. Epidemiology of asthma

A large-scale study on the prevalence of asthma in children was completed. A sample of approximately 20,000 was studied, covering nine Schools in different parts of Delhi. It was observed that nearly 11% of children had asthma. The factors determining the occurrence of asthma were studied. It was more common in males, in those who had a family history of asthma and in those who had smokers at home in the families. Place of residence and socioeconomic status did not emerge as significant determinants.

20. Defects of lipid metabolism in asthma

It was established that there are abnormalities in lipid metabolism in asthmatics that could be involved in the pathogenesis of asthma. Raised levels of lysophosphatidylcholine (LPC) were reported along with increased esterified cholesterol in plasma of asthmatics. Later, raised HDL cholesterol was reported.

21. Decreased activities of calcium homeostatic pumps in asthma

Decreased activities of sodium and calcium adenosine triphosphatase enzymes were reported. A defect in intracellular calcium and sodium homeostasis was proposed. Subsequently, increased sodium and calcium fluxes were found in leukocytes of asthmatics. These abnonnalities were suggested to be involved in the pathogenesis of asthma.

22. Quiet breathing technique for measuring specific airways conductance in guinea pigs and human beings

A body plethysmographic technique for measurement of specific airways conductance in non anaesthetized spontaneously breathing guinea pigs was developed. Later on, it was adapted for human beings to provide a quiet-breathing technique for SGaw measurements in patients.

23. Development of a sensitive test for small airways disease

A body plethysmographic technique was described for determination of specific airways conductance at residual volume. It was found to be a sensitive test for small airways function.

24. Clinical and physiological implications of failure of calcium homeostatic pumps in asthma and their modulation by inhaled corticosteroids

A study to understand the clinical and physiological implications of failure of calcium homeostatic pumps in asthma was completed. It was found that the failure of calcium homeostatic pumps correlated well with the clinical severity of the disease. Further, treatment with a short-term course of prednisolone and long- term course of inhaled steroids increased the activities of these pumps, lowered intracellular calcium levels and resulted in significant clinical improvement.

25. Studies on health hazards of air pollution

Delhi is one of the most polluted cities in the world. The levels of various pollutants including oxides of nitrogen, sulphur dioxide, suspended particulate matter and ozone are often greater than the permissible limits. The impact of air pollution on health and its role in the causation of respiratory morbidity were studied. This was the first such study to be carried out in Delhi. It was observed that residents of more polluted areas in Delhi had greater prevalence of chronic cough and chronic phlegm and poorer lung function.

26. Study of respiratory morbidity among traffic policemen

The respiratory morbidity among traffic policemen was studied. As traffic policemen carry out their duties amidst vehicular traffic, they are likely to be the most exposed to air pollutants of vehicular origin. After a standardized respiratory symptoms questionnaire administration and examination, these subjects were put through a battery of lung function tests including spirometry, lung volume and diffusion coefficient measurements, body plethysmography to measure specific airways conductance at FRC and at RV and histamine bronchoprovocation test. While there was no gross lung function abnormality, increased bronchial reactivity and decreased specific airways conductance at RV were two significant, observations. These suggest that traffic policemen do suffer from adverse effects of exposure to air pollution.

27. Bronchodilator responsiveness in asthma and its modulation by corticosteroids

A study to study the patterns of bronchodilator responsiveness in asthma was started. The modulation of responsiveness by a short-course of a moderately high dose of prednisolone is also being investigated.

28. Bronchodilator response to ipratropium bromide and salbutamol in the normal elderly subjects

A study to compare the bronchodilator efficacy of an anticholinergic agent (ipratropium bromide) and a beta-adrenergic agonist (salbutamol) in the normal elderly subjects was completed. Both the drugs were found to be effective bronchodilators with the latter giving a slightly better response.

29. Advantages of a modified maximum expiratory flow volume maneuver in assessment of severity of asthma

A study was carried out to evaluate the advantage of modifying the maximum expiratory flow volume maneuver by allowing the subject to relax in the latter part of the test. The modified maneuver yielded a significantly greater vital capacity in moderately and severely obstructed asthmatics and was easier to perform without affecting the acceptability and the reproducibility.

30. Development of the guinea pig asthma model

An ovalbumin-induced model of asthma was developed in guinea pigs. The model was found to be satisfactory with demonstration of both early and late phase asthmatic responses, increased bronchial hyperresponsiveness and bronchial tissue and bronchoalveolar lavage eosinophilia. The model will be useful to study therapeutic interventions in asthma.

31. Effect of high dietary sodium and inhibition of NaK adenosine triphosphatase on induction of asthma in guinea pigs

High dietary intake has been reported in epidemiological studies to be a risk factor in the development of asthma. We have earlier shown that the activity of Na K adenosine triphosphatase correlates very well with the severity of asthma, with failure of the enzyme being associated with an acute exacerbation. A study is being carried out in the guinea pig model to study the role of high dietary intake of salt and digoxin-induced inhibition of Na K adenosine triphosphatase on the induction of allergen-induced asthma.

32. Study of the patterns of bronchodilator responsiveness in chronic COPD

It has been observed that contrary to the usual description of COPD as a disease of irreversible airways obstruction, many patients with COPD often show a significant bronchodilator response. A study is currently on to identify factors that determine bronchodilator responsiveness in COPD and the patterns of such a response.

33. Smoking and respiratory morbidity

A population-based study of the effect of smoking on respiratory morbidity has been completed. While 37% of current smokers had chronic respiratory symptoms, only 13% among non-smokers had these. The frequency of symptoms increased with increasing intensity of smoking. However, asymptomatic smokers had a lung function not significantly different from that among asymptomatic non-smokers.

34. Longitudinal study of lung function

A long-term longitudinal study of lung function has been started to define the age-related decline in lung function measurements.