A case of chronic obstructive pulmonary disease associated with central alveolar hypoventilation diagnosed by exercise test

Objective To discuss the characteristics of cardiopulmonary exercise test(CPX) and its value in the evaluation of status in the patients with Chronic obstructive pulmonary disease (COPD). Methods Forty two male patients with stable COPD as the test group and thirty one healthy men were respectively measured pulmonary function test (PFT), CPX and 6 minute walking test (6MWT), and the COPD group were recorded the modified Medical Research Council (mMRC). The comparation of the two groups in the index of PFT, CPX and 6MWT were analyzed, meanwhile in the COPD group the correlation between the index of CPX and PFT, 6MWT and mMRC were also measured.All these were summarized to evaluate the value of CPX in patients with COPD. Results ①In COPD group, the forced expiratory volume in 1st second (FEV1), forced expiratory volume in 1st second/forced vital capacity (FEV1/FVC) and the ratio of FEV1 in predicted value (FEV1%pred) were lower than the control group (P<0.01). Maximal work rate (Wmax), maximal oxygen uptake(VO2max), the ratio of maximal oxygen uptake to weight (VO2max/kg), oxygen pulse (O2 pulse), anaerobic threshold (AT), maximal exercise ventilation (VEmax), and breathing reserve(BR) of COPD group were all lower than the control group (P<0.01). The heart rate reserve(HRR), ventilatory equivalent of carbon dioxide(VE/VCO2) in COPD group were higher than the control group (P<0.05). ②In COPD patients, the Wmax, VEmax and FVC, FEV1, FEV1%pred were revealed a moderate positive correlation (P<0.01), and the VO2max and FVC, FEV1 were also characterised a moderate positive correlation (P<0.01), conversely the AT was weakly positive correlated with FEV1 (P<0.05), while PFT's ventilation index had no correlation with the O2 pulse, VE/VCO2 and BR.③The CPX classification and PFT classification had poor consistency (Kappa=0.076, P=0.097). ④In COPD patients the Wmax was negatively correlated with mMRC (P<0.05), meanwhile which was positively correlated with 6MWT (P<0.05). Unfortunately, there was almost no correlation between the FVC, FEV1, FEV1/FVC, FEV1% pred and mMRC, 6MWT. Conclusions Compared with PFT, CPX can comprehensively reflect the status of patients with COPD.In addition to reflecting the decline of ventilatory function in COPD patients, checking CPX also can observe the ventilation efficiency, evaluate its peripheral skeletal muscle function, earlier to detect the increased pulmonary artery pressure and the potential cardiovascular dysfunction.On the whole, CPX was superior to assess patients′ dyspnea and exercise tolerance, and can reflect the prognosis of COPD patients. Key words: Chronic obstructive pulmonary disease; Cardiopulmonary exercise test; Pulmonary function test; Dyspnea score; 6 minute walking test

Objective To investigate risk signals appeared in subjects performing progressive maximal exercise testing and measures to be taken. Methods Progressive symptom-limited exercise testing was performed in 198 patients. Oxygen uptake(VO2 ) and carbon dioxide output (VCO2) were measured breath-by breath. Arterial oxygen saturation, ECG and blood pressure were monitored during the testing. Arterial blood samples were drawn both at rest and maximal exercise in patients with chronic obstructive pulmonary disease(COPD). Results 155 subjects reached their maximal exercise, 43 were terminated exercising because of risk signals which included desaturation (14 cases), higher or lower systolic blood pressure( 3 cases), arrhythmia ( 16 cases), and ischaemic ST-segment changes ( 10 cases). In patients with COPD,there was a little decrease in PaO2 from (91.58±9.46) mm Hg at rest to (88. 92±13.66) mm Hg at exercise,but the PaCO2 increased significantly from (40. 64±4.26) mm Hg at rest to (43.05±3.16) mm Hg at peak exercise. Conclusions Exercise testing is safe for most patients only if we monitor throughout the test,terminate the test when abnormal signs appear. Key words: Exercise testing ; Risk

Objective To analyze the influencing factors of ventilatory efficiency in patients with chronic obstructive pulmonary disease (COPD). Methods Sixty-seven patients with stable COPD were selected to collect age, sex, height, weight and other basic information, calculate body mass index (BMI), perform pulmonary function and cardiopulmonary exercise test, and determine the forced vital capacity (FVC), forced expiratory volume in one second (FEV1), carbon dioxide equivalent ventilation in rest (EqCO2rest), carbon dioxide equivalent ventilation in anaerobic threshold (EqCO2at), carbon dioxide equivalent ventilation in maximum movement (EqCO2max), established multiple linear regression equation to analyze the influencing factors of ventilatory efficiency in patients with COPD. Results (1)The parameters EqCO2rest, EqCO2at and EqCO2max were set as dependent variables Y1, Y2 and Y3 respectively.Sex, age, height, weight and BMI were set as independent variables X1, X2, X3, X4 and X5.Establishing multiple linear regression equation were Y1=47.357-0.505×X5, Y2=46.894-0.202×X4, Y3=43.394-0.527×X5.(2)BMI of COPD patients was negative correlated with EqCO2rest, EqCO2at and EqCO2max (r=-0.430, -0.403, -0.394, all P<0.001). (3)the parameters of patients with COPD in different BMI groups were compared: EqCO2rest in obese group (31.2±4.5) was lower than that in normal weight group (37.6±6.7), and the difference was statistically significant (P=0.001). EqCO2at in obesity group (28.9±4.2) was lower than that in normal weight group (35.1±6.5), and the difference was statistically significant (P=0.001). EqCO2max in obesity group (26.1±3.7) was significantly lower than that in normal weight group (32.8±6.5) and overweight group (30.9±6.4) (P<0.001, 0.016, respectively). (4)There were significant differences compared with EqCO2max and EqCO2rest, EqCO2at in the low weight group (P=0.045, 0.044, respectively), compared with EqCO2rest and EqCO2max in normal weight group and obesity group, and the difference was statistically significant (P=0.007, 0.001 respectively). Conclusions The ventilation efficiency of patients with COPD increases significantly during maximal exercise, and the obesity COPD patients may have higher ventilation efficiency. Key words: Pulmonary disease, chronic obstructive; Cardiopulmonary exercise test; Carbon dioxide equivalent ventilation; Body mass index

Point/Counterpoint

Objective To investigate the effects of target heart rate by caculated directing lower extremity sub-maximal exercise rehabilitation with COPD patients. Methods Forty cases of outpatients in People′s Hospital of Shanghai Pudong District from Junuary 2013 to February 2014 were assigned randomly to pulmonary rehabilitation group and control group with 20 each.The pulmonary rehabilitation group accomplished lower extremity sub-maximal exercise rehabilitation about 30 minites for 3 times each week in 12 weeks.Measuring maximum exercise heart rate.Each case did not stop cycling until the exercise intensity increased to sub-maximal exercise target heart rate by formula: (maximum heart rate-quiet heart rate)×70%.Compared pulmonary function before and after rehabilitation.The frequency of acute exacerbation and the first time of acute exacerbation were followed up for 1 years after discharge. Results There was no significant difference of FVC%pred, FEV1%pred and FEV1/FVC between two groups The values of IC%predafter exercises (60.0±8.9)% were significantly higher than before (49.4±5.9)%in the pulmonary rehabilitation group (P<0.01) while there was no significant difference in contrast group.The frequency of acute exacerbation in the pulmonary rehabilitation group [(1.1±1.0) times] was significantly lower than contrast group [(2.1±1.4) times](P<0.05). The first time of acute exacerbation in the pulmonary rehabilitation group (34.0±14.2) weeks was significantly longer than contrast group (24.5±14.6) weeks (P<0.01). Conclusions Lower extremity submaximal exercise rehabilitation under target heart rate guidance could increase patient′s IC, improve lung ventilation during exercise, reduce the frequency of acute exacerbation, delay to aggravate the attack again feasiblely and effectively. Key words: Chronic obstructive pulmonary disease; Rehabilitation; Target heart rate; Acute exacerbation

Year in review 2012: Asthma and chronic obstructive pulmonary disease

To explore the characteristics of oxygen uptake efficiency (OUE) in patients with chronic obstructive pulmonary disease (COPD), and to analyze the relationship between OUE and the exercise capacity. Pulmonary function test and cardiopulmonary exercise test were performed in 59 patients with stable COPD (grade I, n = 15; grade II, n = 16; grade III, n = 19; grade IV, n = 9) and 29 healthy volunteers of the same age. Their successive breathing respiratory exchange parameters were collected and analyzed. t test and χ(2) test were used for 2 sample comparison, while multiple comparisons among groups were performed by using single factor analysis of variance. Correlation analysis was done by Pearson correlation test. Compared with the normal control group [(2.2 ± 0.4) L·min(-1)·lg(L·min(-1))(-1); (35 ± 4) ml/L], the OUES and OUEP of the COPD patient group [(1.9 ± 0.3) L·min(-1)·lg(L·min(-1))(-1); (31 ± 5) ml/L]were significantly lower (t = 4.57, 3.39, all P < 0.01) . The OUE of the grade I patients showed no significant difference compared with the normal control group (t = 0.36-1.49, all P > 0.05), while the OUES of the grade II-IV patients [(2.05 ± 0.26), (1.76 ± 0.28) and (1.63 ± 0.19) L·min(-1)·lg(L·min(-1))(-1)] decreased significantly compared to the normal control group [(2.23 ± 0.39) L·min(-1)·lg(L·min(-1))(-1); t = 2.42-5.26, all P < 0.05]. The OUEP and the OUE at the anaerobic threshold of the grade II-III patients [(31 ± 4) and (31 ± 5), (29 ± 5) and (29 ± 5) ml/L] decreased significantly compared to the normal control group [(35 ± 4) and (34 ± 4) ml/L, t = 2.18-4.83, all P < 0.05]. The OUES, OUEP and the OUE at the anaerobic threshold in COPD patients were correlated (r = 0.500-0.625, all P < 0.01) positively with the exercise tolerance (peak VO2% pred). The oxygen uptake efficiency of patients with COPD is significantly reduced compared to that of the normal subjects, and is correlated positively with the exercise capacity.

Objective To investigate the efficacy of rehabilitation for patients with stable chronic obstructive pulmonary disease (COPD) by the modified exercise prescription of reduced lip-abdominal breathing plus Liu Zi Jue.Methods The 100 patients were randomly divided into four groups,including control group,reduced lip-abdominal breathing group,Liu Zi Jue group,exercise prescription group.Each group had 25 patients.The lung function,6 min walking distance (6MWD) and artery blood gas analysis were measured before exercise and after keeping exercising for six months.Results The exercise prescription group significantly improved more than control group,reduced lip-abdominal breathing group and Liu Zi Jue group in the lung function FEV1,FEV1 ％pred and 6MWD and artery blood gas analysis.It had a statistically significant.Conclusions Modified exercise prescription of reduced lip-abdominal breathing plus Liu Zi Jue can significantly improve lung function and improve exercise capacity in patients with COPD,and it is significantly better than single reduced lip-abdominal breathing and Liu Zi Jue exercise. Key words: [Key words] Reduced lip-abdominal breathing; Liu Zi Jue; Exercise prescription; Chronic obstructive pulmonary disease

The burden of chronic obstructive pulmonary disease (COPD) remains very high. Till recently clinical approach of COPD patients was focused on measuring airflow limitation during exercise and treating airway obstruction with inhaled bronchodilators and corticosteroids. This approach stems from an old definition of COPD, mainly consisting of airflow limitation with poor reversibility after bronchodilation. The concept of COPD has changed strikingly in the last years. Many recent studies have shown that COPD is a systemic disease affecting not only the lungs but many other organs of the patient. Laboratory cardiopulmonary exercise testing assesses physiological and biological reserves. However, it is not the most suitable test to assess the functional state of a systemic disease such as COPD. We need simpler exercise tests that can be used on larger scales. The 6-minute walk test has been shown to be highly reproducible and reflects real life limitations of these patients better. It allows precise measurements of medical intervention and is a good predictor of mortality, provided clinicians respect the defined standards of this test. It should be associated with a more systemic index such as the BODE index to better find disease-modifying interventions and improve the outcome of COPD patients. On the other hand routine measurement of spirometry in the general population by primary care physicians should be promoted as it decreases smoking habits and helps better detecting and management of COPD patients. Specialists should support primary care physicians to spread these new concepts of COPD throughout the medical community.

Objective To evaluate the effect of inhaling ipratropium bromide(IPB)to patients with chronic obstructive pulmonary disease(COPD)on ventilation and exercise capacity during exercise.Methods All 12 stable patients were diagnosed as COPD.Before and after inhaling single-dose IPB,symptom-limited progressive cycle ergometer exercise tests were performed.Results The maximal rate of work,maximal oxygen uptake,the maximal volume of ventilation per minute and the maximal ratio of tidal volume to inspiratory capacity increased significantly after inhaling IPB solution of four times the standard dose.The maximal dead space/tidal volume ratio and the maximal ventilatory equivalent for CO2 had no change.There was a significant correlation between the amount of the maximal ratio of tidal volume to inspiratory capacity improved and amount of maximal oxygen uptake improved(r=0.598,P＜0.05).Another significant correlation exited between the amount of maximal rate of work improved and amount of the maximal ratio of tidal volume to inspiratory capacity improved(r=0.743,P＜0.05).Conclusions Inhaling single-dose IPB will be helpful in improving exercise tolerance of patients.The improvement of maximal ratio of tidal volume to inspiratory capacity could be an important factor about inhaling IPB how to improve exercise tolerance of patients. Key words: Chronic obstructive pulmonary disease; Pulmonary function; Exercise test; Ipratropium bromjde

Chronic obstructive pulmonary disease (COPD) is one of respiratory system chronic diseases which have serious effect.Cardiopulmonary exercise test (CPET) is a preferred method to assess decline of physiological function and exercise tolerance,it is also useful on work out pulmonary rehabilitation program,and the evaluation of the effects of treatment and rehabilitation for patients with COPD.There are many result in walk test which have good correlation with CPET,especially 6 minutes walk test and shuttle walk test.That makes walk test be widly used in COPD in evaluation of clinical observation and assessment of treatment effect. Key words: 6 minutes walk test; Cardiopulmonary exercise test; Chronic obstructive pulmonary disease

Objective To investigate nutrition status and dyspnea in the patients with chronic obstructive pulmonary disease (COPD) between GOLD Ⅱ and GoLD Ⅲ, and test the evaluative validity of disease status by GOLD classification of COPD. Methods Thirty patients with clinically stable COPD were recruited, including 15 patients of GOLD Ⅱ of COPD and 15 patients of GOLD Ⅲ of COPD. Body mass index (BMI), triceps skin-fold thickness (TSF), serum albumin (Alb), and partial pressure of oxygen in arterial blood (PaO2) were measured in each patient. Dyspnea was assessed by the Borg Scale (BS). Exercise stress test was taken by incremental exercise test. Results BMI was significantly lower in the patients of GOLD Ⅲ than that in the patients of GOLD Ⅱ[(19±5 ) kg/m2 vs (23±3) kg/m2,p < 0.05]. TSF was significantly reduced in the patients of GOLD Ⅲ than that in the patients of GOLD Ⅱ[ (8±3) mm vs(13±5) mm, P < 0.01]. Alia in the patients of GOLD Ⅲ was significantly decreased than that in the patients of GOLD Ⅱ [(32±7) g/L vs (36±6) g/L, P <0.05]. The difference of PaO2 between the patients of GOLD Ⅲ and the patients of GOLD Ⅱ was significant [(72±9) nun Hg (1 mm Hg = 0.133 kPa ) vs (78±8) nun Hg, P < 0.01], and the significant difference of BS was found between the patients of GOLD Ⅲ and the patients of GOLD Ⅱ( 5.0±2.0) grades vs (3.0±1.0) grades, P <0.05 ]. In addition, 12 patients in the patients of GOLD Ⅱ took the exercise stress test and 8 patients were found anaerobic threshold (AT), 5 patients in the patients of GOLD Ⅲ took the exercise stress teat and no AT was found. Conclusions The parameters of BMI, TSF, Alb and PaO2 are significantly reduced in the patients of GOLD Ⅲ than those in the patients of GOLD Ⅱ. In the patients of GOLD Ⅲ, BS is higher than that in the patients of GOLD Ⅱ and AT is difficult to obtain, suggesting more severe in degree of impairment. GOLD classification of COPD reflects the disease stares and prognosis in the patients with COPD, as a valuable parameter in clinical practice. Key words: Pulmonary disease, chronic obstructive; Nutrition assessment; Dyspnea

Objective The aim of the current study was to determine if the slowed exercise oxygen uptake (VO2) kinetics would be accompanied by delayed recovery VO2 kinetics in patients with severe chronic obstructive pulmonary disease (COPD). Methods We evaluated 37 patients with severe COPD and 17 normal people, who had the pulmonary function test(PFT)and cycle ergo meter cardiopulmonary exercise test (CPET) studies to maximum tolerance. Gas exchange was calculated breath by breath.Results MRT and τRec for VO2 in patients with COPD were consistently found longer than the controls ( P<0. 010),and correlated well with peak VO2, peak VO2 % pred, VO2/kg and VE( P <0.001), also the parameters from PFT, such as FEV1% pred. FEV1/FVC、 MVV% pred. RV% pred、 RV/TLC and Rtot%pred( P<0.001). Conclusions Exercise and recovery VO2 kinetics were slowed. Measurement of exercise and recovery VO2 kinetics improve the accuracy of the exercise electrocardiogram diagnosis of COPD. Key words: Cardiopulmonary exercise test; Oxygen uptake kinetics; Chronic obstructive pulmonary disease

The purpose of this study was to compare the exercise responses in normal subjects and subjects with chronic obstructive pulmonary diseases (COPD). Eleven stable COPD patients from outpatient department and 9 persons with no known cardiopulmonary diseases served as the subjects of the study. Cardiopulmonary responses to maximal workload during an incremental exercise test and submaximal steady-state exercises of three intensities, 50%, 60%, and 70% VO2max respectively, were studied. No differences in resting or preexercise data between the groups were found. Subjects with COPD attained comparable breathing frequency (Fb), heart rate (HR), oxygen pulse, ventilatory equivalent for O2 and CO2 (VE/V02, VE/VCO2), and O2 pulse with the normal controls, but significantly lower workload (WL), oxygen consumption (V02), minute ventilation (VE), tidal volume (Vt), and respiratory exchange ratio (RER) at maximal exercise. Five-minute postexercise lactate level was also significantly lower in patient group. The absolute values of all these parameters required for 50%, 60%, and 70% VO2max in COPD patients were not significantly different from the values in normal subjects. However, VE as a percentage of achieved maximal values was significantly higher in these three exercise intensities in COPD patients. Minute ventilation for intensities of 50%, 60%, and 70% VO2max were found to be 51.1±5.9%, 62.2±10.6%, and 70.3±9.0% of the patients' maximal VE.

Objective To evaluate the relationship of the exercise capacity in patients with stable moderate to severe chronic obstructive pulmonary disease(COPD) with the lung function tests, especially the inspiratory capacity(IC). Methods Pulmonary lung function test(PFT) and cardiopulmonary exercise test(CPET) were tested in 62 patients with stable moderate to severe COPD and 30 controls, and measured the parameters of ventilation and gas exchange. Results IC%pred was significant associated with exercise capacity(r=0.74, P<0.001)in COPD, it has significant validity of the prediction to peak O2%pred. Conclusions IC%pred provides the efficient information to estimate the exercise capacity in patients with stable COPD, and its predictive value is better than other parameters. Key words: Chronic obstructive pulmonary disease; Inspiratory capacity; Cardiopulmonary exercise testing