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PubMed2006

The connection between chronic obstructive pulmonary disease symptoms and hyperinflation and its impact on exercise and function.

Forced expiratory volume in 1 second (FEV1) has served as an important diagnostic measurement of chronic obstructive pulmonary disease (COPD) but has not been found to correlate with patient-centered outcomes such as exercise tolerance, dyspnea, or health-related quality of life. It has not helped us understand why some patients with severe FEV1 impairment have better exercise tolerance compared with others with similar FEV1 values. Hyperinflation, or air trapping caused by expiratory flow limitation, causes operational lung volumes to increase and even approach the total lung capacity (TLC) during exercise. Some study findings suggest that a dyspnea limit is reached when the end-inspiratory lung volume encroaches within approximately 500 mL of TLC. The resulting limitation in daily physical activity establishes a cycle of decline that includes physical deconditioning (elevated blood lactic acid levels at lower levels of exercise) and worsening dyspnea. Hyperinflation is reduced by long-acting bronchodilators that reduce airways resistance. The deflation of the lungs, in turn, results in an increased inspiratory capacity. For example, the once-daily anticholinergic bronchodilator tiotropium increases inspiratory capacity, 6-minute walk distance, and cycle exercise endurance time, and it decreases isotime fatigue or dyspnea. Pulmonary rehabilitation and oxygen therapy both reduce ventilatory requirements and improve breathing efficiency, thereby reducing hyperinflation and improving exertional dyspnea. Thus, hyperinflation is directly associated with patient-centered outcomes such as dyspnea and exercise limitation. Furthermore, therapeutic interventions--including pharmacotherapy and lung volume--reduction surgery--that reduce hyperinflation improve these outcomes.

Bronchodilator Agents↗

PubMed1994

Effect of a home exercise training program in patients with cystic fibrosis.

Physical training in patients with pulmonary diseases, including cystic fibrosis (CF), may improve exercise tolerance in these patients. Most training programs are performed in a clinical setting. Little information is available concerning the effect of home exercise training programs in CF patients. The purpose of this study was to investigate the effect of a home exercise training program in CF patients. Ten adolescent patients (seven male and three female) with CF, mean (SD) age 20.6 (6.5) years, participated in a home exercise training program for 3 months. Pretraining condition was assessed during a control period of 2 months in which patients were asked to continue their normal daily activities. Home exercise training consisted of cycle training of 15 min at a submaximal workload once a day and was supervised by a physiotherapist two times a week. A follow-up period of 1 month, in which the patients were advised to continue cycling at home without supervision, was included after the training program. Pulmonary function, bicycle exercise test performance, and the degree of limitation in activities of daily living (ADL) were measured. No significant differences were found between the two pretraining assessments. After the training period we found significant improvement in maximal exercise capacity (Wmax) (mean [SEM]: 126 [10] W before and 146 [11] W after; p = 0.004), maximal oxygen uptake (VO2max) (mean [SEM]: 31.4 [2.1] ml.kg-1.min-1 before and 36.5 [2.5] ml.kg-1.min-1 after; p = 0.008), oxygen pulse (VO2/HR) (mean [SEM]: 10.9 [0.66] ml before and 11.9 [0.74] ml after; p = 0.047), and degree of limitation in ADL (mean [SEM]: 2.4 [0.43] before and 1.5 [0.48] after; p = 0.019) as compared with the initial values. Since no significant differences were found between the posttraining values and the results at the end of the follow-up period, the patients were apparently able to maintain the training effects during the follow-up period. We conclude that in CF patients, a home exercise training program, after clinical assessment of exercise tolerance, is an effective and relatively simple treatment to improve physical performance and decrease limitation in ADL and should be included in the maintenance treatment in these patients.

Activities of Daily Living↗

PubMed1996

[Functional results of surgical lung volume reduction in severe pulmonary edema].

BASIC PROBLEM AND OBJECTIVE OF THE STUDY: Lung volume reduction (LVR) is a new surgical approach designed to relieve shortness of breath and improve exercise tolerance in patients with severe lung emphysema. The aim of this study was to analyse changes of lung function, gas exchange, exercise tolerance and degree of dyspnoea one and 3 months after LVR. PATIENTS AND METHODS: Seventeen patients (15 men and two women; mean age 53 [38-68] years) with severe emphysema (six with alpha 1-PI deficiency) underwent unilateral (n = 14) or bilateral (n = 3) LVR surgery. One week before and one and 3 months after surgery pulmonary function tests, arterial blood gas analysis at rest breathing room air, 6-minute walking distance and dyspnoea score (Medical Research Council Scale) were determined. RESULTS: There was a significant increase in forced expiratory vital capacity after one second (FEV1, P < 0.001), and a significant decrease in total lung capacity (TLC, P < 0.0001) and residual volume (RV, P < 0.0001). The mean increase in FEV1 was 39% and in PaO2 9%. The mean decrease in TLC was 20%, in RV 26% (P < 0.001; both comparisons), and in paCO2 4% (not significant). The mean 6-minute walking distance increased by 96% from 229 to 405 meters (P < 0.0001). The mean dyspnoea score on a five point scale (0-4 points) decreased by 52% from 3.4 to 1.6. With the exception of the improved inspiratory vital capacity the postoperative results at one and 3 months after LVR did not differ significantly. All patients were alive 3 months postoperatively. CONCLUSIONS: In patients with severe emphysema surgical LVR shows significantly improved pulmonary function, gas exchange, dyspnoea and walking distance as assessed one and three months postoperatively. The early mortality seems to be low.

Acute Disease↗

PubMed2001

Prognostic factors in medically treated patients with chronic pulmonary embolism.

OBJECTIVE: To evaluate risk factors in medically treated patients with chronic pulmonary embolism (CPE) who are not suitable candidates for definitive surgical therapy. STUDY DESIGN: A total of 53 consecutive patients with angiographically confirmed CPE were involved. Four patients underwent pulmonary endarterectomy, and 49 patients received continuous anticoagulation therapy and were followed up over an average period of 18.7 months (range, 6 to 72 months). RESULTS: Sixteen patients died during the follow-up period, mostly from progressive right ventricle failure. Among the nonsurvivors, 12.5% had distal CPE and 87.5% had proximal CPE (p = 0.03). The survivors had a higher (mean +/- SD) level of PaO(2) (59.3 +/- 11 mm Hg) than the nonsurvivors (50.8 +/- 9 mm Hg; p = 0.02), a lower mean pulmonary artery pressure (mPAP; 30.3 +/- 15 mm Hg vs 51 +/- 21 mm Hg; p = 0.0004), a lower hematocrit value (40.0 +/- 6 vs 44.2 +/- 6; p = 0.03), and better exercise tolerance (4.8 +/- 3 multiples of resting O(2) consumption [METs] vs 2.5 +/- 1 METs; p = 0.02) achieved during the maximal symptom-limited exercise. The patients with coexisting COPD had a higher mortality rate (62.5%) than those without COPD (37.5%; p = 0.04). Independent risk factors in the Cox analysis were as follows: mPAP (p = 0.04), exercise tolerance (p = 0.02), and COPD (p = 0.04). In the Kaplan-Meier analysis, the patient group with lower mortality achieved > 2 METs (p = 0.02) and had mPAP < 30 mm Hg (p = 0.04). CONCLUSION: The prognosis for the medically treated CPE patients, particularly those with pulmonary hypertension, was unfavorable. The prognostic factors for these patients were mPAP, coexistence of COPD, and severe exercise intolerance.

Anticoagulants↗

PubMed2005

Exercise and training in mitochondrial myopathies.

The intriguing concept of exercise training as therapy for mitochondrial disease is currently unsettled: in the unique setting of mitochondrial heteroplasmy, what are the effects of chronic exercise on skeletal muscle containing a mixture of mutated and wild-type mitochondrial DNA (mtDNA)? Furthermore, what are the consequences of habitual physical inactivity on mitochondrial heteroplasmy? In patients with mtDNA defects, deleterious effects of limited physical activity likely magnify the mitochondrial oxidative impairment contributing to varying degrees of exercise intolerance. Normal adaptive responses to endurance training offer the potential to increase levels of functional mitochondria, improving exercise tolerance. The few clinical studies assessing such training effects in patients with mtDNA defects have unequivocally demonstrated physiologic and biochemical adaptations that improve exercise tolerance and quality of life. Uncertain, however, is the training effect on mitochondrial heteroplasmy. To determine therapeutic advisability of endurance training, it remains imperative to establish whether: reported increases in mutant mtDNA levels can be offset by increases in absolute wild-type mtDNA levels; and chronic physical inactivity leads to a selective down-regulation of wild-type mtDNA. Resistance exercise training offers an alternate, innovative therapeutic approach in patients with sporadic mtDNA mutations; exercise-induced transfer of normal mtDNA templates from muscle satellite cells to mature myofibers, thereby lowering mutation load (increasing functional mitochondrial load). Efficacy and safety of this approach needs to be replicated in a larger group of patients. Currently, appropriate recommendation (either in support or against) exercise training in mitochondrial disease is lacking, which is frustrating for physicians and disheartening for patients. Although considerable progress has been made, an immediate urgency exists to resolve the effects of chronic exercise on skeletal muscle in patients with heteroplasmic mtDNA mutations.

DNA, Mitochondrial↗

PubMed1982

[Improved angina-free work tolerance up to 6 years following bypass operation according to degree of revascularization].

Bypass surgery improves exercise performance in a high percentage of patients with effort angina. The influence of the degree of revascularization on the extent and duration of improvement of exercise parameters was evaluated in 415 patients with angiographically determined degrees of revascularization (REV) by serial exercise testing 1-6 years after bypass surgery. Patients with three different degrees of REV are compared. REV I: All vessels up to 50% stenosed have a patent graft. REV II: The main vessel supplying the left ventricle (LV) has a patent graft. REV III: The main vessel supplying the LV has not a patent graft but at least one additional graft is patent. Angina-free exercise tolerance in watts, the maximum double product (HR X BP), and the percentage of patients with angina pectoris and ST-segment depression during exercise were recorded. In patients with REV I and II the angina-free exercise tolerance was improved up to 6 years after bypass surgery but in patients with REV III only 2 years afterwards. Patients with REV I, REV II, and REV III showed improvement of all three parameters for 6 years, 4 years and 1 year respectively. The completeness of revascularization is an important determinant in the longterm improvement of postoperative exercise parameters up to 6 years after surgery.

Angina Pectoris↗

PubMed2004

[Cardiometabolic therapy of ischemic heart disease].

A total of 59 patients suffering from ischemic heart disease with effort angina (functional classes II-IV) entered the study. Of them, 29 patients received antianginal drugs and 10-day courses of a combination of drugs with membran-oprotective properties (MPD); 30 patients received antianginal drugs alone. Blood levels of lipid peroxidation products, lipid structure of erythrocytic membrane, exercise tolerance were studied before and after the treatment. MPD therapy was associated with lower activity of lipid peroxidation, stabilization of cell membrane structure and greater exercise tolerance due to more effective cardiac performance.

Angina Pectoris↗

PubMed2002

Physical training for cystic fibrosis.

BACKGROUND: Physical training may form an important part of the care package for patients with cystic fibrosis. OBJECTIVES: To determine whether a prescribed regime of physical training produces improvement or prevents deterioration in physiological and clinical outcomes in cystic fibrosis compared to no training. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group specialist trials register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books of conference proceedings. Date of the most recent search: August 2001. SELECTION CRITERIA: All randomised controlled clinical trials in which a prescribed regime of physical training is compared to no physical training in patients with cystic fibrosis. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion, assessed methodological quality and extracted data. MAIN RESULTS: Of the sixteen trials identified six trials, which included 184 patients, met the inclusion criteria. Exercise tolerance in the short term, during an acute admission was improved in patients who received physical training. In a three year study there was no improvement in exercise tolerance at the end of the study period. Over three years there was a significantly greater mean annual rate of decline in FVC in the control group compared to the exercise group WMD 2.17 (95%CI 0.47, 3.87). Changes in other lung function parameters showed a similar trend, but these were not statistically significant. REVIEWER'S CONCLUSIONS: Conclusions about the efficacy of physical training in cystic fibrosis are limited by the small size, short duration and incomplete reporting of most of the trials included in this review. Physical training is already part of the care package offered to most patients with cystic fibrosis and there is no evidence to actively discourage this. Further research is needed to assess comprehensively the net benefit of the addition of physical training to the care of cystic fibrosis patients.

Cystic Fibrosis↗

PubMed2004

Improvement after lung volume reduction surgery: a role for inspiratory muscle adaptation.

In severe emphysema, lung volume reduction surgery (LVRS) can improve lung function and exercise tolerance. The maximal changes of forced expiratory volume in 1s (FEV(1)) and lung volume occur early after surgery, whereas maximal improvement of exercise tolerance occurs later. We tested the hypothesis that secondary adaptation of inspiratory muscles could explain this delayed clinical improvement. In that purpose, we evaluated nine consecutive patients before LVRS and up to 9 months post-operatively. Six weeks after LVRS, we observed an increase in FEV(1) and 6 min walk distance (6MWD). The gain in sniff nasal inspiratory pressure (SNIP) was inversely proportional to lung volume loss. Values of FEV(1) and lung volume were maintained throughout follow-up whereas SNIP values significantly increased from 6 weeks to 6 months post-LVRS. In the meantime, we observed an increase in 6MWD correlated with the SNIP increase. This suggests that in patients undergoing LVRS, early improvement of SNIP is proportional to decrease in lung volume whereas the further delayed improvement may be due, at least in part, to adaptation of the inspiratory muscles.

Adult↗

PubMed1985

Role of isosorbide dinitrate in management of chronic congestive heart failure.

Congestive heart failure is accompanied by a number of compensatory mechanisms that may overshoot the mark. Among these are excessive arteriolar and venous constriction. Nitrates are effective in producing venodilation, redistributing blood from the chest to the periphery, and lowering right and left atrial pressures. Although oral isosorbide dinitrate is effective in producing acute beneficial hemodynamic effects, it usually does not increase exercise tolerance in the short term. Prolonged administration, however, does increase exercise tolerance and improve clinical class. Isosorbide dinitrate can be effectively combined with an arteriolar dilator such as hydralazine, which increases cardiac output. Such vasodilator therapy is symptomatically effective in patients with heart failure, although there is no evidence to date to suggest a prolongation of life.

Administration, Oral↗

PubMed1995

[The clinico-hemodynamic effects of the antioxidant ceruloplasmin in IHD patients].

Ceruloplasmin- and placebo-treated CHD patients were studied for severity of angina pectoris, changes in central hemodynamics, exercise tolerance. It is shown that ceruloplasmin promoted an increase in exercise tolerance, higher quality of life, arrest of the disease progress. Combined treatment of CHD incorporating ceruloplasmin produced a positive effect on central hemodynamics and contractile, pump capacities of the myocardium.

Angina Pectoris↗

PubMed2002

The Italian multicentre study on noninvasive ventilation in chronic obstructive pulmonary disease patients.

Chronic obstructive pulmonary disease (COPD) patients with chronic ventilatory failure (CVF) are more likely to develop exacerbations, which are an important determinant of health-related quality of life (HRQL). Long-term noninvasive positive-pressure ventilation (NPPV) has been proposed in addition to long-term oxygen therapy (LTOT) to treat CVF but little information is available on its effects on HRQL and resource consumption. Therefore, the current authors undertook a 2-yr multicentric, prospective, randomised, controlled trial to assess the effect of NPPV+ LTOT on: 1) severity of hypercapnia; 2) use of healthcare resources, and 3) HRQL, in comparison with LTOT alone. One hundred and twenty-two stable hypercapnic COPD patients on LTOT for > or = 6 months were consecutively enrolled. After inclusion and 1-month run-in, 90 patients were randomly assigned to NPPV+LTOT (n=43) or to LTOT alone (n=47). Arterial blood gases, hospital and intensive care unit (ICU) admissions, total hospital and ICU length of stay and HRQL were primary outcome measures; survival and drop-out rates, symptoms (dyspnoea and sleep quality) and exercise tolerance were secondary outcome measures. Follow-up was performed at 3-month intervals up to 2 yrs. Lung function, inspiratory muscle function, exercise tolerance and sleep quality score did not change over time in either group. By contrast the carbon dioxide tension in arterial blood on usual oxygen, resting dyspnoea and HRQL, as assessed by the Maugeri Foundation Respiratory Failure Questionnaire, changed differently over time in the two groups in favour of NPPV+LTOT. Hospital admissions were not different between groups during the follow-up. Nevertheless, overall hospital admissions showed a different trend to change in the NPPV+LTOT (decreasing by 45%) as compared with the LTOT group (increasing by 27%) when comparing the follow-up with the follow-back periods. ICU stay decreased over time by 75% and 20% in the NPPV+LTOT and LTOT groups, respectively. Survival was similar. Compared with long-term oxygen therapy alone, the addition of noninvasive positive-pressure ventilation to long-term oxygen therapy in stable chronic obstructive pulmonary disease patients with chronic ventilatory failure: 1) slightly decreased the trend to carbon dioxide retention in patients receiving oxygen at home and 2) improved dyspnoea and health-related quality of life. The results of this study show some significant benefits with the use of nocturnal, home noninvasive positive-pressure ventilation in patients with chronic ventilatory failure due to advanced chronic obstructive pulmonary disease patients. Further work is required to evaluate the effect of noninvasive positive-pressure ventilation on reducing the frequency and severity of chronic obstructive pulmonary disease exacerbation.

Aged↗

PubMed2002

Do transmyocardial and percutaneous laser revascularization induce silent ischemia? An assessment by exercise testing.

BACKGROUND: Transmyocardial and percutaneous laser revascularization (TMR, PTMR) may reduce angina and increase exercise tolerance in otherwise untreatable angina patients, although the mechanism is unknown and the placebo effect may be significant. One other proposed mechanism is cardiac denervation leading to silent ischemia. METHODS: Electrocardiograms obtained during symptom-limited exercise (ETT, modified Bruce protocol) at baseline and 12 months were analyzed (blinded core laboratory) from 182 patients randomized to TMR (n = 92) or medical therapy alone (MED(TMR), n = 90) and 219 patients randomized to PTMR (n = 109) or medical therapy alone (MED(PTMR), n = 110). RESULTS: Exercise duration increased 1 year after TMR or PTMR relative to medically treated patients (6.8 +/- 3.4 min vs 8.6 +/- 3.5 min for TMR; 7.3 +/- 3.1 min vs 9.1 +/- 3.6 min for PTMR, P <.05). At baseline, 20% of TMR and MED(TMR) subjects had ST depression >1.0 mm, >80% had angina during exercise, but only 3% had ST changes without chest pain (silent ischemia). This did not change after TMR. In the PTMR group, more subjects exercised to >1.0 mm ST depression (from 17% to 34%, P <.05), with no change in MED(PTMR), but the proportion with silent ischemia did not change in either group. CONCLUSION: Exercise tolerance improved after TMR and after PTMR. Relative to PTMR, TMR more effectively suppressed pain during exercise and ischemic ST depression. However, neither TMR nor PTMR induced significant silent ischemia. These results suggest that denervation may not be a significant factor contributing to angina relief after these procedures. The contribution of the placebo effect was not determined by these results.

Adult↗

PubMed2006

Reduction of hyperinflation by pharmacologic and other interventions.

Hyperinflation of the lungs is associated with activity limitation and reduced quality of life of patients with chronic obstructive pulmonary disease (COPD). Cardiopulmonary exercise testing has proven useful, not only in establishing this link, but also in determining which interventions modify exercise endurance and the mechanisms by which this is achieved. In COPD, dynamic hyperinflation is reduced during exercise by interventions that either increase the potential for expiratory flow or increase the time available for expiration. Two classes of intervention improve exercise tolerance by increasing expiratory flow. Bronchodilators reduce expiratory airflow resistance by increasing the diameter of the airways. An alternative intervention, though less practical, is to reduce the density of the gas exhaled through obstructed airways, such as occurs when breathing a mixture of helium and oxygen (heliox). In contrast, supplemental oxygen and exercise rehabilitation programs improve endurance by reducing respiratory ventilatory drive and, therefore, respiratory rate. The different mechanisms exploited by these interventions to reduce dynamic hyperinflation suggest that combination treatments should yield additive benefits. This has been proven in the case of combinations of rehabilitative exercise training with supplemental oxygen, or with the bronchodilator tiotropium, both of which have been found to yield additive effects. With such interventions, we already have options for improving the mobility of patients with COPD. With a firm understanding of the physiologic basis of exercise limitation, we can focus on defining new and better strategies to improve exercise tolerance.

Bronchodilator Agents↗

PubMed1999

Comparison of transmyocardial revascularization with medical therapy in patients with refractory angina.

BACKGROUND: Transmyocardial revascularization involves the creation of channels in the myocardium with a laser to relieve angina. We compared the safety and efficacy of transmyocardial revascularization performed with a holmium laser with those of medical therapy in patients with refractory class IV angina (according to the criteria of the Canadian Cardiovascular Society). METHODS: In a prospective study conducted between March 1996 and July 1998 at 18 centers, 275 patients with medically refractory class IV angina and coronary disease that could not be treated with percutaneous or surgical revascularization were randomly assigned to receive transmyocardial revascularization followed by continued medical therapy (132 patients) or medical therapy alone (143 patients). RESULTS: After one year of follow-up, 76 percent of the patients who had undergone transmyocardial revascularization had improvement in angina (a reduction of two or more classes), as compared with 32 percent of the patients who received medical therapy alone (P<0.001). Kaplan-Meier survival estimates at one year (based on an intention-to-treat analysis) were similar for the patients assigned to undergo transmyocardial revascularization and those assigned to receive medical therapy alone (84 percent and 89 percent, respectively; P=0.23). At one year, the patients in the transmyocardial-revascularization group had a significantly higher rate of survival free of cardiac events (54 percent, vs. 31 percent in the medical-therapy group; P<0.001), a significantly higher rate of freedom from treatment failure (73 percent vs. 47 percent, P<0.001), and a significantly higher rate of freedom from cardiac-related rehospitalization (61 percent vs. 33 percent, P<0.001). Exercise tolerance and quality-of-life scores were also significantly higher in the transmyocardial-revascularization group than in the medical-therapy group (exercise tolerance, 5.0 MET [metabolic equivalent] vs. 3.9 MET; P=0.05); quality-of-life score, 21 vs. 12; P=0.003). However, there were no differences in myocardial perfusion between the two groups, as assessed by thallium scanning. CONCLUSIONS: Patients with refractory angina who underwent transmyocardial revascularization and received continued medical therapy, as compared with similar patients who received medical therapy alone, had a significantly better outcome with respect to improvement in angina, survival free of cardiac events, freedom from treatment failure, and freedom from cardiac-related rehospitalization.

Aged↗

PubMed1997

Exercise performance in children with asthma: is it different from that of healthy controls?

Exercise tolerance and possible limitation in work capacity of asthmatic children is still a matter of debate. The aim of this study was to compare ventilation and gas exchange response to exercise of asthmatic children with that of healthy controls. Exercise performance was evaluated in 80 children with mild-to-moderate asthma, aged 7-15 yrs, and in 80 healthy controls matched for age, height, weight and habitual level of physical activity. The children performed a maximal exercise test on a treadmill, during which oxygen uptake (V'O2), carbon dioxide output (V'CO2) and minute ventilation (V'E) were measured continuously. No premedication was given to the asthmatic children. Forced expiratory volume in one second (FEV1) at rest was 93+/-11% of predicted in asthmatic children and 95+/-9% pred in controls. After the run, the mean fall in FEV1 was 13.9% (range 0-57%) and 1.6% (0-9%), respectively (p<0.001). The two groups achieved similar maximum oxygen uptake (V'O2,max) ((mean+/-SD) 40.3+/-8.4 and 42.6+/-9.6 mL x min(-1) x kg(-1) in asthmatics and controls, respectively; NS) and maximum minute ventilation output (V'E,max) (42.9+/-14.8 and 45.7+/-14.9 L x min(-1) respectively; NS). The kinetics of V'O2, V'CO2 and V'E during the test revealed no differences between the two populations. Moreover, anaerobic threshold and oxygen pulse were the same in the two groups. Asthmatics showed a ventilatory pattern with lower respiratory frequencies and greater tidal volumes during the run. These results suggest that asthmatic children can achieve a level of exercise performance similar to that of healthy children, provided that they have a comparable level of habitual physical activity. The only difference found concerned the ventilatory pattern of the asthmatic children, which was characterized by a reduced respiratory frequency and greater tidal volume at the same minute ventilation. The level of physical conditioning was found to be the main determinant of exercise tolerance for children with controlled asthma.

Adolescent↗

PubMed1999

Pulmonary gas exchange and exercise capacity in patients with systemic lupus erythematosus.

OBJECTIVE: Exercise tolerance is often reduced in patients with systemic lupus erythematosus (SLE). Mechanisms have been proposed but the underlying causes have not yet been elucidated. The study of pulmonary gas exchange during exercise may be helpful in revealing circulatory, ventilatory, and metabolic abnormalities. We hypothesized that in SLE, exercise aerobic capacity would be reduced due to chronic inactivity and poor muscle energetics. METHODS: Thirteen women with SLE and low disease activity were studied; 5 age matched subjects served as controls. Clinical examination, chest radiography, electrocardiogram, and pulmonary function test were all normal. Subjects underwent 1 min incremental cycle ergometer exercise to exhaustion. Oxygen uptake (VO2), CO2 output (VCO2), minute ventilation (VE), heart rate (HR), and arterial O2 saturation were monitored. Anaerobic threshold (AT), VO2/HR, deltaVO2/deltaWatt, respiratory rate (RR), Ti/Ttot, VE/VCO2, and breathing reserve (BR) were computed. RESULTS: At rest, patients exhibited high VE, respiratory alkalosis, and a wide alveolar-arterial O2 gradient [(A - a)O2] during 50% O2 breathing. Other indexes of respiratory function were within the normal range. In the 6 patients with SLE where pulmonary artery systolic pressure at Doppler echocardiography was measurable, mean level was in the upper limits of normal. During exercise, maximal aerobic capacity was reduced in all patients (VO2 peak, 1098+/-74 vs. 2150+/-160 ml/min, p<0.01; AT, 36 +/-3 vs. 48+/-3% predicted VO2 max, p<0.05). Ventilation adjusted for the metabolic demand (VE/VCO2 at AT) was increased (31+/-1 vs. 24+/-1; p<0.05). A normal breathing pattern was observed during all tests. No patient stopped exercising because of ventilatory limitation (i.e., they had normal breathing reserve). CONCLUSION: Reduced muscle aerobic capacity is common in SLE and is most likely because of peripheral muscle deconditioning. Increased ventilatory demand, secondary to diffuse interstitial lung disease, is not a significant contributor to the reduction in exercise tolerance.

Adult↗

PubMed1999

[Surgical and functional results after surgical lung volume reduction in 94 patients with severe emphysema].

Lung volume reduction (LVR) is a new surgical approach designed to relieve shortness of breath and improve exercise tolerance in patients with severe lung emphysema. The aim of this study was to analyse surgical results and changes in the lung function, gas exchange, exercise tolerance and degree of dyspnoea until two years after LVR. From June 1994 to September 1997 ninety-four patients (31 women and 63 men, mean age 64 [35-79] years) with severe emphysema (12 with alpha 1-Pi-deficiency) underwent unilateral (n = 24) or bilateral (n = 70) LVR. 92 from 94 patients were extubated immediately after surgery. 30 days mortality was 2.2% (2/94), 90 days 3.3% (3/94) respectively. Most common postoperative complications were pneumonia (n = 15, 16%) and air leakage longer than 7 days (n = 22, 23.4%). One month after surgery there was a significant increase in forced expiratory vital capacity after one second (FEV1 59%) and significant decrease in total lung capacity (TLC 19%) and residual volume (RV 28%). Also significant changes were observed in paO2, paCO2, 6-minute walking distance, dyspnoea score and respiratory muscle function. Two years after LVR lung function tests in patients with smokers emphysema showed the benefit to be maintained (high responders). Patients with alpha 1-Pi-deficiency showed 6 to 12 months after surgery a remarkable deterioration of functional data (low responders). In selected patients with severe emphysema surgical LVR shows significant improved pulmonary function, gas exchange, dyspnoea and walking distance. The results are better after bilateral operation. Patients selection, rehabilitation program and interdisciplinary care resulted in a low operative morbidity and mortality.

Adult↗