**12. Prognosis and follow-up**

Several parameters correlate with prognosis in COPD, including forced expiratory volume in 1 second (FEV1), diffusion capacity for carbon monoxide (DLCO), blood gas measurements, body mass index (BMI), exercise capacity, clinical status and radiographic findings on CT scan. A widely used simple prognostication tool is the BODE index, which is based on the BMI, obstruction (FEV1), dyspnea (using Medical Research Council Dyspnea Scale), and exercise capacity (ie, 6-minute walk distance).

The 6-min walk test (6MWT) remains the most popular test for the evaluation of exercise tolerance in COPD patients. It is simple and well standardised, but its interpretation criteria remain controversial. A distance of <361m also predicted mortality in patients with FEV1, 50% predicted. The 6MWT is currently used to evaluate the impact of treatment. The classical 54 m is defined as the minimal significant difference to detect benefit of treatment

Current Overview of COPD with Special Reference to Emphysema 149

Saetta,2008 as cited in Bourdin A,2009). The best described population of Treg is CD4+, and

Scores used in clinical practice to assess health status have been modified to be useful in primary care setting. The simplified version of the original BODE index, BOD score and a new index called ADO(age, dyspnoea and airflow obstruction) have been studied and found to have similar accuracy for risk prediction(Puhan et al.,2009 as cited in Bourdin A,2009).

Thoracic gas compression during forced expiration is a major event in COPD and a new index of gas compression defined as (NFEV1-FEV1)/NFEV1 (in percent) was demonstrated to be higher at baseline in COPD (32%) than in controls (10%) and it decreased after albuterol only in COPD patients. Shuttle walk test for exercise testing, negative expiratory pressure(NEP) method and forced oscillation technique(FOT) to measure expiratory flow limitation(EFL), single-breath nitrogen washout test(SBN2) for small airway involvement, inspiratory muscle endurance(IME) for monitoring respiratory muscle training, diaphragmatic electromyogram(EMG) for neural respiratory drive, etc include some of the modalities to assess clinical function, response to treatment and some for purely research

Newer imaging techniques have recently allowed for the possibility of evaluating pulmonary function as well as anatomy. Although helical CT and HRCT have become the cornerstone of pulmonary imaging, newer modalities such as PET and MRI may soon become critical components in the arsenal of tests used to evaluate pulmonary disease. Newer axial CT is as accurate as fiberoptic bronchoscopy (FOB) and virtual bronchoscopy (VB), or CT bronchography, has received considerable attention and excellent internal images of the tracheobronchial tree can be generated to the level of the 4th-5th generation

Increasing evidence in support of therapy with phosphodiesterase-4 inhibitors, antioxidants and augmentation therapy with A1PI in deficient individuals, seem promising. Nonrespiratory treatments of co-morbidities with medications such as proton pump inhibitors, angiotensin-converting enzyme inhibitors, and statins show promise in the management of COPD. Bronchoscopic lung volume reduction (bLVR) is being developed to collapse areas of emphysematous lung in hopes of having the same effect on respiratory function as LVRS, but without the morbidity and mortality of surgery. Safety and effectiveness of minimally invasive approaches like video-assisted thoracoscopy for the

Chronic obstructive pulmonary disease is a common condition with a high morbidity

 The Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines COPD as a preventable and treatable disease characterized by progressive permanent airflow limitation that is not fully reversible. The airflow limitation is associated with an abnormal inflammatory response on exposure to noxious particles or gases particularly

 There is substantial overlap and co-existence of emphysema, chronic bronchitis, and asthma. Injury from smoking excites inflammation, which leads to cellular and

expresses CD25 and a transcription factor FOXP3.

treatment of giant bullae is under evaluation.

evaluations.

bronchi.

**14. Summary** 

and mortality.

cigarette smoking.

(Redelmeir et al.,1997 as cited in Shapiro SD,2010). The shuttle walk test offers the advantages of being perfectly standardized and highly related to peak oxygen consumption.

Health status is mostly impaired by exacerbations on the one hand and dyspnoea on the other, with its negative effect on daily activity. Some extrapulmonary parameters are also correlated with measures of daily activity, independent of GOLD stage and BODE score; they include left cardiac dysfunction (as assessed by levels of B-type natriuretic peptide and echocardiography) and systemic inflammation (C-reactive protein levels) (Watz et al.,2008 as cited in Shapiro SD,2010). Frequent exacerbations have a negative long-term impact on the BODE index, a well known prognostic factor in COPD, and are not purely respiratory episodes but associated with systemic inflammation.
