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SUMMARY AND CONCLUSIONSThis work was carried out to evaluate the possible contributory mechanisms of exercise intolerance and fatigue in COPD patients.Twenty (20) isolated, stable COPD patients were included in this study (moderate and severe COPD patients). Patients were selected from chest outpatients clinic and who were admitted to chest department during the period from October 2003 to October 2004.The following were performed for all patients:(1) Through medical history:(2) Clinical examination.(3) Radiological examination:(a) Plain chest X-ray.(b) Echocardiography.(4) Laboratory examination:(a) Some selected liver function tests (Albumin, SGOT, SGPT, Bilirubin).(b) Some selected kidney function tests (Blood urea, serum creatinine).(c) Complete blood picture.(d) Fasting and 2 hours postprandial blood sugar.(5) Spirometric ventilatory function tests:(a) FEV1, FVC, MEF25-75.(b) Inspiratory capacity (IC) pre and post exercise.(6) Electrocardiography (ECG).(7) Arterial blood gases analysis (ABG).(8) Nutritional examination:(a) Ideal body weight percentage (IBW%).(b) Body mass index (BMI).(c) Serum albumin level.(d) Peripheral blood lymphocytes.(9) Musculo-skeletal & neurological examination:(a) Inspection for detection of wasting.(b) Measurement of quadriceps strength (QF).(c) Isometric hand grip strength (HGS).(10) Electrolytes assessment:(a) Serum sodium (Na).(b) Serum potassium (K).(c) Serum magnesium (Mg).(11) Assessment of the quality of life by using short form-36 (SF-36) questionnaire (Ridely et al., 1997 and Shuman, 2000).(12) Psychometric examination by using Beck Depression Inventory (BDI).(13) Exercise testing:(a) Six-minute walk test (6 MWT).(b) Cycle ergometer exercise test.The results were tabulated and statistically evaluated revealing the following:(1) Increased number of patients tolerant to 6MWT than patients tolerant to cycle ergometer [14 (70%) & 3 (15%) respectively].(2) COPD patients who were tolerant to cycle ergometer were tolerant to 6 MWT.(3) Current smoker COPD patients were intolerant to cycle ergometer when compared with COPD patients with no smoking history and this was statistically significant (P<0.001).(4) No significant difference between exercise intolerance and duration of COPD (P>0.05).(5) No statistical significant difference between exercise intolerance and number of exacerbation in last year in COPD patients (P>0.05).(6) Moderate COPD patients were tolerant than severe COPD patients with highly statistical significant difference in cycle ergomerter (P<0.05).(7) Dyspnea and leg pain together were the most common cause of exercise intolerance in 6MWT and in cycle ergometer exercise test (66.7% & 52.9% respectively).(8) Tolerant COPD patients in 6 MWT had higher resting ventilatory function than intolerant patients in 6 MWT and this increase was statistically significant (P<0.05) in FEV1(L), FEV1% & FVC,MEF25-75 and inspiratory capacity (IC) pre and post exercise.(9) Tolerant COPD patients in cycle ergometer had higher resting ventilatory function than intolerant patients in cycle ergometer and this increase was statistically significant in MEF25-75 and inspiratory capacity (IC) pre and post exercise (P<0.05).(10) There was a significant positive correlation of 6 MWT tolerance and FEV1 & FVC, MEF25-75 (P<0.05) and a highly significant negative correlation with IC at rest and post exercise (P<0.005).(11) There was a highly significant positive correlation of cycle ergometer tolerance and MEF25-75 (P<0.005) and a significant negative correlation with IC at rest (P<0.05).(12) Under weight was detected in 4 patients (20%) as IBW < 90% while it was detected in 3 patients (15%) as BMI < 20 and this decrease was statistically significant (P<0.001 & P<0.05) respectively.(13) Over weight was detected in 2 patients (10%) as IBW > 115% while it was detected in 8 patients (40%) as BMI > predicted 25 and this increase was statistically significant (P<0.001) as regard IBW only.(14) No statistical significant differences in mean values of some nutritional parameter (BMI, IBW% and lymphocytes) as regard exercise tolerance in 6 MWT & cycle ergometer (P>0.05).(15) There was a highly statistical significant positive difference in mean value of albumin level as regard exercise tolerance in 6MWT (P<0.01) and no statistical difference in mean value of albumin level as regard exercise tolerance in cycle ergometer.(16) There was a highly significant positive correlation between 6MWT tolerance and albumin (P<0.01), but no correlation between cycle ergometer tolerance and albumin.(17) Hyponatraemia was detected in 3 patients (15) and this decrease was statistically significant (P<0.001).(18) Hypokalemia was detected in 10 patients (50%) and this decrease was not statistically significant (P>0.05).(19) Hypermagnaesemia was detected in 1 patient (5%) and this increase was statistically significant (P<0.001).(20) There was no statistical significant difference in mean values of some electrolytes as regard exercise tolerance in 6 MWT and cycle ergometer.(21) There was no correlation between exercise tolerance in 6 MWT and cycle ergometer and electrolytes parameters.(22) Right ventricular hypertrophy was detected in 16 patients (80%) by echocardiography and this was statistically significant (P<0.001).(23) tricuspid regurge was detected in 3 patients (15%) and this was statistically significant (P<0.001).(24) Right atrial dilatation was detected in 2 patients (10%) and this was statistically significant (P<0.001).(25) All patients involved in this study had pulmonary hypertension.(26) Tolerant patients in cycle ergometer had lower value of mean pulmonary artery pressure than intolerant patients and this decrease was statistically significant (P<0.05).(27) There was a significant negative correlation between tolerant cycle ergometer and pulmonary artery pressure (P<0.05).(28) There was a significant negative correlation between tolerant 6 MWT and right atrial dilatation (P<0.05).(29) There was no statistical significant difference in mean values of arterial blood gases parameters and exercise tolerance in 6 MWT and cycle ergometer.(30) There was no correlation between exercise tolerance in 6 MWT and cycle ergometer and arterial blood gases.(31) Tolerant patients in 6 MWT and in cycle ergometer had higher mean value of quadriceps force and this increase was statistically significant (P<0.05) and highly significant (P<0.005) in 6 MWT and cycle ergometer respectively.(32) There was a significant positive correlation between tolerant 6 MWT and quadriceps force (P<0.05) and there was a highly significant positive correlation between tolerant cycle ergometer and quadriceps force (P<0.005).(33) There was no significant correlation between exercise tolerance and handgrip strength.(34) There was statistical difference between patients with skeletal muscle wasting and those with no wasting as regard exercise intolerance in cycle ergometer.(35) There was no correlation between exercise tolerance in 6 MWT & cycle ergometer and wasting of skeletal muscles.(36) Physical domain of SF-36 score measuring HRQL (as a measure of fatigue) was below normal individual in 19 patients (95%) and this decrease was statistically highly significant (P< 0.001) while mental combined score was below healthy individual in 6 patients (40%) and this decrease was statistically significant (P< 0.05).(37) There was a significant positive correlation between exercise tolerance in 6 MWT and cycle ergometer and physical domain (PCS)of HRQL (P<0.05).(38) There was a significant positive correlation between physical combined score (PCS) and FEV1 & quadriceps force (P<0.05) while there was a significant negative correlation between PCS and duration of COPD & Beck depression inventory (P<0.05).(39) Mild to moderate depression score was detected in 3 patients (15%) and this increase was statistically significant (P< 0.001).(40) Tolerant patients in 6MWT had lower mean value in BDI than intolerant 6 MWT patients and this decrease was statistically highly significant (P<0.005) while no statistical significant difference was detected in mean value of BDI as regard tolerant cycle ergometer.(41) There was a highly significant negative correlation between 6 MWT tolerance and BDI and no correlation between cycle crgometer tolerance and BDI.(42) According to multiple regression analysis, the sole contributor to exercise intolerance in 6 MWT was quadriceps force, duration of COPD and physical combined score (PCS).(43) According to multiple regression analysis, the sole contributor to exercise intolerance in cycle ergometer was FEV1 & quadriceps force and physical combined score.(45) There was a highly significant positive correlation between walked distance in 6 MWT and quadriceps force (P<0.005) while there was a highly significant negative correlation with BDI (P<0.005) and had significant negative correlation with duration of COPD (P<0.05), right a trial dilatation (P<0.05) and wasting of skeletal muscles.CONCLUSION(1) The problem of exercise intolerance and fatigue in COPD patients is preferred to be handled through a global approach.(2) The most prominent single component of exercise intolerance and fatigue in COPD patients seems to be the state of skeletal muscles (namely limb muscles).(3) Cycle ergometer may be considered as a more efficient tool in revealing exercise intolerance in COPD patients when compared to six minute walk test.RECOMMENDATIONS(1) A more extensive research in the field of skeletal muscles involvement in COPD patients is strongly advised (the domains of pathogenesis, therapeutic challenges and prognostic score are possible fields of interest).
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