ExErcisE tEsting in assEssmEnt and managEmEnt of PatiEnts in clinical PracticE - PrEsEnt situation

It is a safe simple and practical test of sub maximal functional capacity, which measures the maximum distance walked by a subject in 6 minutes. Advantage of this test is that it provides an acceptable index of functional disability and correlates with oxygen uptake measured during comprehensive testing. This test gives very limited information regarding physiological contributors to activity related symptoms or about mechanism of exercise limitation. Currently this test is used in lung transplantation, lung volume reduction surgery, pulmonary rehabilitation and in predicting mortality in cardiac patients and patients with pulmonary vascular disorders.

objeCtIve 1) To review recent scientific advances in exercise testing methods and results that is important for a clinical practioner.
2) To understand the utility and limitations of different methods of exercise testing.
3) To understand appropriate method in assessment and management of patients.

4)
To appreciate that exercise testing results can have greater clinical meaning when interpreted in context of relevant patient information. 5) To understand that additional study is required to further characterize both current and future roles of exercise testing in clinical medicine.

INtRoDUCtIoN
The need of the hour is to understand the different methods used worldwide to asses the patients exercise performance and response in clinical practice.
Clinical Exercise Testing (CET) is increasingly gaining importance in clinical medicine, by helping the clinician to objectively evaluate the physiological functions. The result helps to predict the outcome and mortality in different clinical circumstances.

CommoN methoDS to ASSeS exeRCISe ReSpoNSe AND peRfoRmANCeS IN CLINICAL pRACtICe
Simple test are easily performed but limits physiological understanding.
More comprehensively performed tests may provide detail information and understanding but is costly and demanding. The clinician has to choose the type of test to perform for a particular patient.
Commonly the following test is performed worldwide:-1) 6 min walk test 2) Shuttle Walk Test 3) Exercise Induced Bronchoconstriction Test 4) Cardiac Stress Test

mINUte WALk teSt
It is a safe simple and practical test of sub maximal functional capacity, which measures the maximum distance walked by a subject in 6 minutes. Advantage of this test is that it provides an acceptable index of functional disability and correlates with oxygen uptake measured during comprehensive testing. This test gives very limited information regarding physiological contributors to activity related symptoms or about mechanism of exercise limitation. Currently this test is used in lung transplantation, lung volume reduction surgery, pulmonary rehabilitation and in predicting mortality in cardiac patients and patients with pulmonary vascular disorders.

ShUttLe WALk teSt
It measures the distance walked by a patient in a 10 meter course, being paced by an audio signals from a cassette. The intensity of exercise reached is comparable to test performed on a treadmill, as the walking speed is progressively increased until the patient reaches exhaustion. Modification of maximal SWT for determination of endurance performance -similar to maximal and constant (sub maximal) cycle ergometry may be done.

exeRCISe INDUCeD bRoNChoCoNStRICtIoN
In this physical activity triggers acute airway narrowing in patients with heightened airway responsiveness. In susceptible patients EIB typically occurs 5to 10 minutes key words : Exercise; heart; Interpretation; methodology; 6min walk test; testing

3.
Evaluation of patients of cardiovascular diseases 4.
Evaluation of Patients of respiratory diseases -COPD -ILD -Pulmonary Vascular Diseases -Cystic Fibrosis 5.
Evaluation for transplantation and Lung Volume Reduction Surgeries 7.
Pulmonary Rehabilitation 8. Impairment disability Table 1 to 11 illustrates the indication, contraindication and guidelines laid down by various international authorities for cardio pulmonary exercise testing in clinical setting.

CoNCLUSIoN
Cardiopulmonary exercise test is a helpful tool for evaluation of the disease and management in clinical practice and rapidly evolving in one of the important investigative and diagnostic test. There are different methods used in various clinical setting. The clinical exercise testing a simple and easy to perform test for a pulmonologist as compared to the other conducted tests and relatively more simpler and cost effective test, which needs to be more frequently used in our day to day clinical practice in relevant patients. Common protocols to be followed include exercise on treadmill or cycle ergometry at a workload of 60 %to 80% of predicted maximum or the intensity that will elicit a heart rate of 80% of predicted maximum for 6 to 8 minutes. The goal is to produce ventilation equal to those attained during activity to produce symptom of EIB.
15% percent decrease in FEV 1 following exercise is diagnostic of EIB.And 10-15 % decrease in FEV 1 would be suggestive of EIB.

CARDIAC StReSS teSt
Common type of exercise testing, the primary purpose of which is diagnosis and management of myocardial infarction. Bruce protocol is commonly used and the single most reliable indication of ischemia is ST segment depression. During this test ECG and BP is measured, but the utility may be enhanced by concurrent measurement of ventilator parameters and respiratory gas exchange.

CLINICAL exeRCISe teStINg (Cet)
CET involves the measurement of respiratory gas exchange i.e. oxygen uptake, carbon dioxide , minute ventilation, other variables while monitoring ECG, blood pressure , pulse oximetry and exertion perceived (Borg Scale) during a maximal symptom limited incremental test on a cycle ergo meter or treadmill. Simultaneous measurement of blood gasses and spirometry provides with more detail information on gas exchange and ventilation.CET provides a global assessment of integrative exercise responses which are not adequately reflected by measurement of individual organ system function on rest. Peak oxygen uptake remains the gold standard for exercise capacity.
It has tradionaly been undertaken with an incremental stepwise or ramp control protocol to exhaustion. In patients of COPD, acute response to an inhaled bronchodilator was assessed using various exercise tests. The authors found endurance time with a constant -workload exercise (80% of maximal work rate)was the most responsive end point to the effect of bronchodilator showing 19% improvement in exercise duration time. Arterial blood gasses measured at 5 minute constant -work exercise testing may give practical and cost effective alternative when arterial oxygen saturation, PaO2, alveolar -arterial oxygen pressure difference and ratio of physiological dead space to tidal volume are required.

Interpretation of Cpet Results
References 37, 38 and 28 * Decreased, normal, and increased are with respect to the normal response.  Review pertinent clinical and laboratory information (clinical status) 3.
Note overall quality of test, assessment of subject effort, and reasons for exercise cessation 4.
Identify key variables: initially Vo 2 , and then HR, VE, Sao 2 , and other measurements subsequently.

5.
Use tabular and graphic presentation of the data 6.
Pay attention to trending phenomena : submaximal through maximal responses. 7.
Compare exercise responses with appropriate reference values.

9.
Establish patterns of exercise responsess. 10. Consider what conditions / clinical entities may be associated with these patterns. 11. Correlae CPET results with clinical status. 12. Generate CPET report.