Factors associated with improvement in breathing capacity during exercise in patients with chronic obstructive pulmonary disease

OBJECTIVES: The aim of this study was to explore the relationship between resting pulmonary function indices and the ratio of minute ventilation at peak exercise to the maximal voluntary ventilation (VEmax/MVV) and to determine whether an improvement in breathing capacity during exercise (i.e. VEmax/MVV > 1) is associated with greater exercise capacity in patients with COPD. METHODOLOGY: The results of pulmonary function tests and incremental, symptom-limited cardiopulmonary exercise testing in 84 patients with predominantly moderate to severe COPD were reviewed. Multiple linear regression analysis was applied to determine the relationship of VEmax/MVV with selected independent variables at rest. Multiple logistic regression was used to determine significant predictors of VEmax/MVV 1. RESULTS: FEV1/FVC and inspiratory capacity (IC) were the only variables among resting pulmonary function indices that were significant independent determinants of VEmax/MVV and the stepwise analysis generated the following equation: VEmax/MVV = (-1.05E-02 x FEV1/FVC) + (0.15 x IC) + 1.28; r= 0.701, P < 0.001. Using multiple logistic regression with VEmax/MVV 1 as a dependent categorical variable, FEV1/FVC was the only significant predictor among resting pulmonary indices of a VEmax/MVV ratio of > 1 (Odds ratio 0.93, 95%CI 0.89, 0.97). There was a significant association between VEmax/MVV and peak oxygen uptake (VO2max) after adjusting for FEV1 (r = 0.66, P < 0.001). If the categorical variable of VEmax/MVV ( 1) was used instead of a continuous variable, a significant association with VO2max remained after adjusting for FEV1 (r = 0.60, P < 0.001). CONCLUSIONS: Among resting pulmonary function indices, the FEV1/FVC ratio is the best determinant of an improvement in breathing capacity during exercise in COPD patients. After adjusting for FEV1, an improvement in breathing capacity during exercise is associated with significantly higher exercise capacity.     

Timing and driving components of the breathing strategy in children with cystic fibrosis during exercise

The aim of this study was twofold: first, to determine the breathing strategies of children with cystic fibrosis (CF) during exercise, and secondly, to see if there was a correlation with lung function parameters. We determined the tension-time index of the inspiratory muscles (T(T0.1)) during exercise in nine children with CF, who were compared with nine healthy children with a similar age distribution. T(T0.1) was determined as followed T(T0.1) = P0.1/PImax . T(I)/T(TOT), where P0.1 is mouth occlusion pressure, PImax is maximal inspiratory pressure, and T(I)/T(TOT) is the duty cycle. CF children showed a significant decrease of their forced expiratory volume in 1 sec (FEV1), forced vital capacity (FCV), and FEV1/FVC, whereas the residual volume to total lung capacity ratio (RV/TLC) ratio and functional residual capacity (FRC) were significantly increased (P < 0.001). Children with CF showed mild malnutrition assessed by actual weight expressed by percentage of ideal weight for height, age, and gender (weight/height ratio; 82.3 +/- 3.6%). Children with CF showed a significant reduction in their PImax (69.3 +/- 4.2 vs. 93.8 +/- 7 cmH2O). We found a negative linear correlation between PImax and weight/height only in children with CF (r = 0.9, P < 0.001). During exercise, P(0.1), P0.1/PImax, and T(T0.1) were significantly higher, for a same percent maximal oxygen uptake in children with CF. On the contrary, T(I)/T(TOT) ratio was significantly lower in children with CF compared with healthy children. At maximal exercise, children with CF showed a T(T0.1) = 0.16 vs. 0.14 in healthy children (P < 0.001). We observed at maximal exercise that P0.1/PImax increased as FEV1/FVC decreased (r = -0.90, P < 0.001), and increased as RV/TLC increased (r = 0.92, P < 0.001) only in children with CF. Inversely, T(I)/T(TOT) decreased as FEV1/FVC decreased (r = 0.89, P < 0.001), and T(I)/T(TOT) decreased as RV/TLC increased (r = -0.94, P < 0.001). These results suggest that children with CF adopted a breathing strategy during exercise in limiting the increase of the duty cycle. Two determinants of this strategy were degrees of airway obstruction and hyperinflation.     

Maximal ventilation at rest and exercise in patients with chronic pulmonary disease

74 subjects of different ages: normal children, 19 boys (A) and 7 girls (C) aged between 11 and 15 years; asthmatic boys (n = 7, group B) and girls (n = 7, group D), with similar ages; normal male adult subjects (n = 10, group E) and pulmonary patients with restrictive (n = 8, group G) or obstructive (n = 16, group F) ventilatory impairment, were submitted to measurements of vital capacity (VC), forced expiratory volume in 1 s, (FEV1), maximal voluntary ventilation (MVV), maximal peak expiratory (PEF) and inspiratory (PIF) flows at rest, and two maximal exercise stress tests in which the ventilation at maximal exercise (MEV) were retained. Indirect MVV was obtained by multiplying the FEV1 by 35 and 37.5. The correlation coefficients between MVV and VC, FEV1, PEF and PIF were always as high as r greater than 0.76. (p less than 0.001), with a discrepancy between the calculated and measured MVV. The average ratio MVV/FEV1 always exceeds 39 and is much higher in groups B, C and G. The mean percent values of the ratio MEV/MVV were 0.63 in normal men and 0.74 in normal boys. In patients, this ratio is higher than in adult normals: F = 0.81 and G = 0.88, and is not due to methodological errors, but seems to correspond to several physiological features playing only a role during exercise (MEV). This work shows the difficulty in predicting correctly the MVV at rest and in assessing the ventilatory reserve during maximal exercise in chronic pulmonary patients.     

Contribution of lung function to exercise capacity in patients with chronic heart failure

BACKGROUND: The importance of exercise capacity as an indicator of prognosis in patients with heart disease is well recognized. However, factors contributing to exercise limitation in such patients have not been fully characterized and in particular, the role of lung function in determining exercise capacity has not been extensively investigated. OBJECTIVE: To examine the extent to which pulmonary function and respiratory muscle strength indices predict exercise performance in patients with moderate to severe heart failure. METHODS: Fifty stable heart failure patients underwent a maximal symptom-limited cardiopulmonary exercise test on a treadmill to determine maximum oxygen consumption (VO2max), pulmonary function tests and maximum inspiratory (PImax) and expiratory (PEmax) pressure measurement. RESULTS: In univariate analysis, VO2max correlated with forced vital capacity (r = 0.35, p = 0.01), forced expiratory volume in 1 s (r = 0.45, p = 0.001), FEV1/FVC ratio (r = 0.37, p = 0.009), maximal midexpiratory flow rate (FEF25-75, r = 0. 47, p < 0.001), and PImax (r = 0.46, p = 0.001), but not with total lung capacity, diffusion capacity or PEmax. In stepwise linear regression analysis, FEF25-75 and PImax were shown to be independently related to VO2max, with a combined r and r2 value of 0. 56 and 0.32, respectively. CONCLUSIONS: Lung function indices overall accounted for only approximately 30% of the variance in maximum exercise capacity observed in heart failure patients. The mechanism(s) by which these variables could set exercise limitation in heart failure awaits further investigation.     

Hypoxemia and hypercapnia during exercise and sleep in patients with cystic fibrosis.

BACKGROUND: In patients with cystic fibrosis (CF), it has been proposed that hypoxemia and hypercapnia occur during episodes of stress, such as exercise and sleep, and that respiratory muscle weakness because of malnutrition may be responsible. METHODS: Pulmonary function, respiratory muscle strength, and nutrition were assessed and correlated with the degree of hypoxemia and hypercapnia during exercise and sleep in 14 patients with CF and 8 control subjects. RESULTS: Despite no differences in maximum static inspiratory pressure (PImax) between the two groups, the CF group developed more severe hypoxemia (minimum oxyhemoglobin saturation [SpO2], 89 +/- 5% vs 96 +/- 2%; p < 0.001) and hypercapnia (maximum transcutaneous CO2 tension [PtcCO2], 43 +/- 6 vs 33 +/- 7 mm Hg; p < 0.01) during exercise. Similarly, during sleep, the CF group developed greater hypoxemia (minimum SpO2, 82 +/- 8% vs 91 +/- 2%; p < 0.005), although CO2 levels were not significantly different (maximum PtcCO2, 48 +/- 7 vs 50 +/- 2 mm Hg). Within the CF group, exercise-related hypoxemia and hypercapnia did not correlate with FEV1, residual volume/total lung capacity ratio (RV/TLC), PImax, or body mass index (BMI). Hypoxemia and hypercapnia during sleep correlated with markers of gas trapping (RV vs minimum arterial oxygen saturation [r = -0.654; p < 0.05]), RV vs maximum PtcCO2 (r = 0.878; p < 0.001), and RV/TLC vs maximum PtcCO2 (r = 0.790; p < 0.01) but not with PImax or BMI. CONCLUSION: Patients with moderately severe CF develop hypoxemia and hypercapnia during exercise and sleep to a greater extent than healthy subjects with similar respiratory muscle strength and nutritional status. Neither respiratory muscle weakness nor malnutrition are necessary to develop hypoxemia or hypercapnia during exercise or sleep.     

Assessing the usefulness of outcomes measured in a cystic fibrosis treatment trial

Forced expiratory volume in 1s (FEV(1)) is the usual primary outcome variable in clinical trials in cystic fibrosis (CF). Usually, several secondary outcomes are also measured. We assessed which secondary outcomes are likely to give additional clinically useful information about treatment effects, in order to inform the design of future studies. The study was performed as part of a trial comparing daily rhDNase with alternate day rhDNase and hypertonic saline in CF. The primary outcome was FEV(1). Secondary outcomes were forced vital capacity (FVC), forced expiratory flow at 25-75% of forced vital capacity (FEF(25-75)), number of pulmonary exacerbations, weight gain, quality of life (QOL), and exercise tolerance. The usefulness of each secondary outcome was investigated by assessing if the change in that outcome over the treatment period could be predicted from the primary outcome. Change in FEV(1) correlated with changes in FVC (r(2)=0.76, P=0.001), FEF(25-75) (r(2)=0.64, P=0.001), weight (r(2)=0.08, P=0.001), and change in oxygen saturation with exercise (r(2)=0.08, P=0.001). However, it did not correlate with changes in visual analogue score (VAS) with exercise, QOL, nor with the occurrence of pulmonary exacerbations. Only the outcomes QOL and VAS with exercise actually provided additional information to FEV(1) in this study.     

Ventilatory capacity and exercise tolerance in patients with chronic stable heart failure

BACKGROUND: Patients with chronic heart failure complain of breathlessness. This is associated with an increase in the ventilatory response to carbon dioxide production (VE/VCO(2) slope), yet a reduction in the maximal ventilation achieved at peak exercise. We analysed ventilatory capacity in heart failure in relation to exercise capacity. METHODS: We analysed data from 74 patients with chronic stable heart failure [age (S.D.) 50.6 (8.8) years; left ventricular ejection fraction 30 (15)%] and 36 controls [48.9 (11.5) years]. Subjects undertook maximal incremental exercise testing with metabolic gas exchange measurements to derive peak oxygen consumption (VO(2)), the VE/VCO(2) slope and ventilation. Spirometry was used to measure FEV(1) and FVC. Maximal voluntary ventilation (MVV) was calculated as FEV(1)x 35. RESULTS: Peak VO(2) was lower in patients [20.9 (7.5) ml min(-1) kg(-1) vs. 34.5 (10.1); P<0.001] and VE/VCO(2) greater [33.4 (10.7) vs. 26.0 (4.7); P<0.001]. Ventilation at peak exercise was lower in patients [63.5 (20.4) l/min vs. 86.9 (29.5); P<0.001], as was MVV [110.1 (37.9) l/min vs. 136.2 (53.1); P<0.001], but ventilation at peak as a proportion of MVV was the same in patients [60.0 (19.0)%] as controls [65.7 (12.4)%)]. There was an inverse relation between peak VO(2) and VE/VCO(2) slope (r=-0. 62; P<0.001). Percentage predicted FEV(1) correlated with ventilation at peak (r=0.62; P<0.001) and inversely with VE/VCO(2) slope (r=-0.32; P<0.001). There was no relation between percentage of MVV achieved and peak VO(2), or VE/VCO(2) slope. CONCLUSIONS: Although ventilation at peak exercise is lower in patients with heart failure than normal subjects, ventilation is the same proportion of maximal voluntary ventilation. These findings suggest that ventilatory capacity does not limit exercise capacity in heart failure.     

Prolonged oxygen kinetics during early recovery from maximal exercise in adult patients with cystic fibrosis

Study objectives: To explore the significance of oxygen kinetics during early recovery after maximal cardiopulmonary exercise testing (CPET) in the assessment of functional capacity and severity of the disease in cystic fibrosis (CF) patients. PARTICIPANTS: Eighteen patients with CF (9 male/9 female; mean +/- SD age, 23 +/- 13 years) and 11 healthy subjects (3 male/8 female; mean age, 29 +/- 4 years) underwent maximum CPET on a treadmill. Breath-by-breath analysis was used for measuring oxygen consumption (VO(2)), carbon dioxide production, and ventilation. Maximum VO(2) (VO(2)peak) and the first-degree slope of VO(2) decline during early recovery (VO(2)/t-slope) were calculated. To assess the severity of the disease, we used standard indexes like FEV(1) (% predicted), VO(2)peak, and a widely accepted system of clinical evaluation, the Schwachman score (SS). RESULTS: VO(2)/t-slope was significantly lower in CF patients compared to healthy subjects (0.61 +/- 0.31 L/min/min vs 1.1 +/- 0.13 L/min/min; p < 0.01) and was closely correlated to FEV(1)(r = 0.90, p < 0.001), VO(2)peak (r = 0.81, p < 0.001), and the SS (r = 0.81, p < 0.001). The multivariate analysis showed that the only independent predictor of the SS is the VO(2)/t-slope. CONCLUSION: We conclude that in CF patients, the prolonged oxygen kinetics during early recovery from maximal exercise is related to the disease severity.     

Spirometry in 3- to 6-year-old children with cystic fibrosis

Spirometry is routinely used to assess pulmonary function of older children and adults with cystic fibrosis (CF); however, few data exist concerning the preschool age group. We have reported normative spirometric data for 3- to 6-year-old children. The current study was designed to assess a similarly aged group of clinically stable patients with CF. Thirty-three of 38 children with CF were able to perform 2 or 3 technically acceptable maneuvers. These patients had significantly decreased FVC, FEV(1), FEV(1)/FVC, and FEF(25-75) when expressed as z scores (number of SD from predicted): -0.75 +/- 1.63, -1.23 +/- 1.97, -0.87 +/- 1.33, and -0.74 +/- 1.63, respectively. There were significant positive correlations of the Brasfield radiological score with FVC and FEV(1) z scores (r(2) = 0.26, p < 0.01 and r(2) = 0.24, p < 0.01). In addition, homozygous patients for the DeltaF508 mutation had lower z scores for FVC (-1.21 versus 0.47, p < 0.01) and FEV(1) (-1.38 versus 0.21, p < 0.05) than heterozygous patients. Of the 14 patients who had full flow-volume spirometric measurements during infancy, 10 had FEF(25-75) z scores greater than -2 at both evaluations. Our findings suggest that spirometry can successfully be used to assess lung function in preschool children with CF and has the potential for longitudinal assessment from infancy through adulthood.     

Spirometric correlates of improvement in exercise performance after anticholinergic therapy in chronic obstructive pulmonary disease.

We wished to determine which resting spirometric parameters best reflect improvements in exercise tolerance and exertional dyspnea in response to acute high-dose anticholinergic therapy in advanced COPD. We studied 29 patients with stable COPD (FEV(1) = 40 +/- 2% predicted [%pred]; mean +/- SEM) and moderate to severe chronic dyspnea. In a double-blind placebo-controlled cross-over study, patients performed spirometry and symptom-limited constant-load cycle exercise before and 1 h after receiving 500 micrograms of nebulized ipratropium bromide (IB) or saline placebo. There were no significant changes in spirometry, exercise endurance, or exertional dyspnea after receiving placebo. In response to IB (n = 58): FEV(1), FVC, and inspiratory capacity (IC) increased by 7 +/- 1%pred, 10 +/- 1%pred, and 14 +/- 2%pred, respectively (p < 0.001), with no change in the FEV(1)/FVC ratio. After receiving IB, exercise endurance time (Tlim) increased by 32 +/- 9% (p < 0.001) and slopes of Borg dyspnea ratings over time decreased by 11 +/- 6% (p < 0.05). Percent change (%Delta) in Tlim correlated best with DeltaIC%pred (p = 0.020) and change in inspiratory reserve volume (DeltaTLC%pred) (p = 0.014), but not with DeltaFVC%pred, DeltaPEFR%pred, or DeltaFEV(1)%pred. Change in Borg dyspnea ratings at isotime near end exercise also correlated with DeltaIC%pred (p = 0.04), but not with any other resting parameter. Changes in spirometric measurements are generally poor predictors of clinical improvement in response to bronchodilators in COPD. Of the available parameters, increased IC, which is an index of reduced resting lung hyperinflation, best reflected the improvements in exercise endurance and dyspnea after IB. IC should be used in conjunction with FEV(1) when evaluating therapeutic responses in COPD.     

Predicting maximal exercise ventilation in patients with chronic obstructive pulmonary disease

Shortness of breath is a chief complaint of many individuals with cardiopulmonary diseases. Exercise testing is often used to help differentiate cardiac from pulmonary involvement. In assessing pulmonary dysfunction during exercise it is essential to know the point at which ventilatory limitation will occur. Numerous authors have presented regression equations based on the FEV1 for predicting either MVV or VEmax. Resting pulmonary function studies were obtained from 53 patients with COPD. Symptom-limited maximal exercise testing was completed on a cycle ergometer using increments of 10 watts/min. Each regression equation for predicting MVV or VEmax was then applied to the data set. Results showed that the FEV1 correlated with the measured VEmax (r = .81) as did PEF (r = .81), MVV (r = .78), IC (r = .78), DCO (r = .68), VA (r = .67), VE (r = .65) and FVC (r = .64). Single post-bronchodilator FEV1 measurements ranged from 0.56 to 1.64 L (mean 1.0 L) while VEmax ranged from 16 to 78 L/min (mean 37.69 L/min). The equation VEmax = 37.5 X FEV1 was the most robust equation found in the literature for predicting VEmax in this sample. This equation was not statistically different from the line of identity when predicted VEmax was plotted against the measured VEmax. The intercept was 0.91 with a slope of 0.98. In addition, this equation had a smaller mean square error in predicting VEmax than those of the other equations investigated.     

稳定期中重度慢性阻塞性肺疾病患者运动时胸腹矛盾呼 …

探讨慢性阻塞性肺疾病患者运动时胸腹矛盾呼吸的影响因素并观察氧疗对胸腹矛盾呼吸的影响。方法３０例稳定期中重度ＣＯＰＤ患者,运动前按常规进行功能检查和血气分析,分别在吸空气和３０％氧气态下进行两次递增负荷运动试验,通过呼吸感应性体表描记仪监测运动过程中胸腹呼吸量之和与实际潮气量之比。     

Normal values and ranges for ventilation and breathing pattern at maximal exercise

Assessment of the breathing pattern at maximal exercise in patients is limited because the range of ventilatory responses (minute ventilation; tidal volume; respiratory rate) at maximal exercise in normal humans is unknown. We studied 231 normal subjects (120 women; 111 men) equally distributed according to age from 20 to 80 years. Each subject performed a progressive incremental cycle ergometer exercise test to their symptom-limited maximum. Mean ventilation at the end of exercise (Vemax) was significantly higher in men (mean +/- SD, 97 +/- 25 L/min) than in women (69 +/- 22 L/min) (p less than 0.001). Minute ventilation at the end of exercise as a fraction of predicted maximal voluntary ventilation (Vemax/MVV) for all subjects was 0.61 +/- 0.14 (range, 0.28 to 1.02). There was no difference in Vemax/MVV between men (0.62 +/- 0.14) and women (0.59 +/- 0.14). Tidal volume at the end of exercise (Vtmax) was higher in men (2.70 +/- 0.48 L) than in women (1.92 +/- 0.41 L) (p less than 0.001). Any differences in Vtmax between men and women disappeared when Vtmax was corrected for baseline FVC. Respiratory rate at the end of exercise (RRmax) was 36.1 +/- 9.2 breaths per minute for all subjects. There was no difference in RRmax between men and women. The Vemax correlated best with carbon dioxide output at the end of exercise (r = 0.91; p less than 0.001) and with maximal oxygen uptake (r = 0.90; p less than 0.001) for all subjects. This study of a large group of subjects has demonstrated the wide range of possible breathing patterns which are adopted during exercise and has provided a wide range of "normal" responses which must be taken into consideration when maximal ventilatory data from exercise tests are analyzed.     

Effects of breathing a normoxic helium mixture on exercise tolerance-of patients with cystic fibrosis

Breathing helium-oxygen (He? O₂,) mixtures of 20.9% O₂/79.1% He has been shown to increase exercise ventilation and peak oxygen uptake in healthy subjects. The improved exercise performance is thought to be due to the reduced density of He? O₂ compared to air and the resulting increases in ventilation. Patients with cystic fibrosis (CF) frequently have abnormal pulmonary function test results, low exercise ventilations and diminished exercise tolerance. This led to the hypothesis that in CF the exercise tolerance of patients might improve when breathing He? O₂. To test this hypothesis, 11 patients with CF or mild to severe airway obstruction performed spirometry and progressive maximal exercise tests while breathing air or He? O₂2. The He? O₂ mixture significantly increased (P <0.05) forced expiratory volume in 1 sec (FEV₁) by 8.2%, peak expired flow by 39%, and maximal voluntary ventilation (MVV) by 17.9% compared to air, while forced vital capacity (FVC) and forced mid-expiratory flow rate (FEF_25–75%,) were unchanged by breathing He? O₂. Ventilation and oxygen uptake at matched submaximal power outputs were not increased while breathing He? O₂. nor were peak exercise ventilation (V?_Epeak) or peak exercise oxygen uptake (V?_O2peak). Estimated hemoglobin saturation and total exercise time were also unchanged during He? O₂, breathing. However, there was a trend for the subjects with the better FEV₁, to increase V?_O2peak. Increases in V?_O2peak when breathing He? O₂, and air were correlated (r = 0.67, P<0.05) with the percent of predicted FEV, values. Still, in the 11 patients as a group, breathing He? O₂, did not significantly improve V?_O2peak V?_Epeak or exercise tolerance. Therefore He? O₂, is unlikely to have additional benefits to patients with CF who use an exercise program to help optimize their health status. Pediatr Pulmonol. 1994;18:206–210 . ©1994 Wiley-Liss, Inc.     

摄氧量平均反应时间在重度慢性阻塞性肺疾病患者心肺功能评估中的应用研究

目的 探讨重度慢性阻塞性肺疾病(COPD)患者在心肺运动试验(cardiopulmonary exercise test,CPET)检测零负荷热身期中的摄氧量动力学改变特点,研究零负荷热身期间摄氧量平均反应时间(mean response time,MRT)与COPD患者心肺功能及常规肺功能的相关性,探讨MRT值评价重...     

Exercise capacity of thoracotomy patients in the early postoperative period

OBJECTIVE: We investigated the mechanism involved with the initial drop and subsequent recovery of exercise capacity in the early postoperative period of thoracotomy patients. METHODS: Sixteen patients (13 who had undergone lobectomy, 3 who had undergone pneumonectomy) underwent a routine pulmonary function test (PFT) and a cardiopulmonary exercise test preoperatively, within 14 postoperative days (POD; post-1; mean +/- SD, 9 +/- 2 POD), and after 14 POD (post-2; mean, 26 +/- 12 POD). RESULTS: After surgery on post-1, PFT results of FVC, FEV(1), and maximum ventilatory volume (MVV) significantly decreased. Oxygen uptake (VO(2)) at a venous blood lactate level of 2.2 mmol/L (La-2. 2), which was adopted as the empirical anaerobic threshold, and maximum V O(2) (VO(2)max) decreased significantly to 88.2 +/- 7.9% and 73.1 +/- 15.4% of the preoperative values, respectively. La-2.2 min ventilation (VE)/ MVV and maximum VEmax)/MVV increased significantly from 0.36 +/- 0.08 to 0. 66 +/- 0.20 and from 0.58 +/- 0.14 to 0.80 +/- 0.09, respectively. On post-2, though La-2.2 VO(2) did not change, VO(2)max improved significantly to 81.5 +/- 19.7% of the preoperative values, in association with significant increases in maximal tidal volume and VEmax, which were produced by significant increases in the PFT results. La-2.2 VE/MVV also decreased significantly to 0.49 +/- 0.13, which indicated a sufficient recovery of respiratory reserve at submaximal exercise. CONCLUSIONS: The initial drop of exercise capacity after lung resection seems to be derived from both circulatory and ventilatory limitations. Further, the subsequent recovery within 1 month seems to be produced by an improvement in ventilatory limitation, which was caused by the surgical injury to the chest wall.     

运动心肺功能与慢性阻塞性肺疾病严重程度相关性分析

目的 探讨心肺运动试验(CPET)与慢性阻塞性肺疾病(COPD)GOLD分级间的相关性,明确何者为优.方法 67例稳定期COPD患者经GOLD分级后,先后进行静态肺通气功能(PFT)、CPET检测.记录FEV1%、FVC%、FEV1/FVC,CPET的最大运动功率(Wmax)、最大运功功率与预计值的比(Wmax%)、最大公斤摄氧量(VO2max)、无氧阈(VO2at AT)、氧脉(O2 Pulse)、最大呼吸频率(RRmax)、呼吸储备(BR%)、最大心率(HRmax)、心率储备(HRR)和每分钟通气量(VE).分析各参数与疾病分期之间的相关性.结果 VO2max、Wmax、O2 Pulse各期间差异有统计学意义;BR%、VE在Ⅰ、Ⅱ期间差异无统计学意义;VO2 at AT在各分期间差异无统计学意义;VO2max、O2 Pulse、VE分别与FEV1%或GOLD分期均显著相关;Wmax、VO2 at AT、BR%与FEV1%或GOLD分期均呈显著相关,而RRmax、HRmax与FEV1%或GOLD分期无相关性.运动受限原因主要有(40/67)为下肢乏力,(9/67)为气促,(7/67)为气促伴下肢乏力.结论 CPET参数与COPD的GOLD分期相关,同时CPET参数与FEV1相关性更高,单纯GOLD分期不能全面评估COPD患者疾病的严重程度,此外,CPET有助于明确运动受限原因.