Effectiveness of salmeterol versus ipratropium bromide on exertional dyspnoea in COPD.

The hypothesis of the study was that salmeterol and ipratropium would have similar dyspnoea ratings during steady-state cycle ergometry at 1 h, but that salmeterol would reduce dyspnoea at 6 h after administration in patients with chronic obstructive pulmonary disease (COPD). The study design was a randomized, double-blind trial in 16 patients (aged 63 +/- 11 yrs) with symptomatic COPD. Two days after familiarization with testing procedures, patients were randomly assigned to receive either two puffs (42 microg) of salmeterol and two puffs of placebo inhaler, or two puffs (36 microg) of ipratropium from each of two inhalers (total, 72 microg). Two days later, patients received the alternative medication. During exercise at 60% of peak oxygen consumption patients rated dyspnoea and performed inspiratory capacity manoeuvres each minute. Forced expiratory volume in one second was 1.13+/-0.48 L (37+/-13% predicted). Dyspnoea ratings were similar for salmeterol and ipratropium at 1 and 6 h. Inspiratory capacity was similar for salmeterol and ipratropium at 1 h, but significantly higher for salmeterol at 6 h (delta = 120 mL; p = 0.03). It is concluded that with the doses used, salmeterol and ipratropium provided similar dyspnoea ratings during exercise at 1 and 6 h after administration.

Target dyspnea ratings predict expected oxygen consumption as well as target heart rate values.

A target heart rate (THR) is the traditional method to prescribe and monitor exercise training intensity in healthy individuals. However, patients with chronic obstructive pulmonary disease (COPD) are limited by ventilatory impairment and dyspnea rather than cardiovascular factors. An alternative approach is to use dyspnea ratings as a target for exercise training in patients with respiratory disease just as ratings of perceived exertion have been used in healthy individuals. The study was a randomized, parallel group trial comparing the ability of patients with COPD to accurately and reliably produce an exercise intensity using a target dyspnea rating (TDR) versus a THR. At Visit 1 patients performed an incremental exercise test on the cycle ergometer, and target values were calculated at approximately 75% of maximal oxygen consumption (V O2). At Visits 2 (3 to 5 d later) and 3 (2 wk later) each patient was instructed to produce a TDR or a THR for 10 min of submaximal exertion. Anthropometric characteristics, lung function, and exercise performance were similar for the 22 patients in each group at Visit 1. For the TDR group the dyspnea target was 2.5 +/- 1.5 at an expected V O2 of 0.88 +/- 0.28 L/min; for the THR group the heart rate (HR) target was 114 +/- 15 beats/min at an expected V O2 of 0.76 +/- 0.29 L/min (p = 0.18 for V O2 between groups). Compared with the expected V O2 from Visit 1, the individual percent differences in V O2 at Visit 2 were -3.9 +/- 18.1% (TDR) and -0.5 +/- 23.2% (THR) (p = 0.58); at Visit 3 the individual percent differences in V O2 were -2.3 +/- 17.0% (TDR) and 2.6 +/- 30.6% (THR) (p = 0.52). The number of patients < 10% and >/= 10% of the expected V O2 were similar for the two groups at Visits 2 (p = 0.38) and 3 (p = 0.27). There were no significant differences for V O2 values (absolute or individual percent) at Visits 2 and 3 for each group and between the groups (p = 0.79). In conclusion, patients with symptomatic COPD demonstrated a comparable ability to use dyspnea ratings and HR as a target to accurately and reliably produce an expected exercise intensity (approximately 75% of V O2max) for 10 min of submaximal exertion.

Comparison of dyspnea ratings during submaximal constant work exercise with incremental testing.

PURPOSE: The purpose of this study was to determine whether dyspnea ratings would be similar during submaximal (as used for training) and incremental (as used in testing) exercise at specific intensities in patients with chronic obstructive pulmonary disease (COPD). METHODS: We studied 20 patients with COPD. Age was 66 +/- 9 yr (mean +/- SD); FEV1 was 43 +/- 14% pred. At Visit 1 patients provided dyspnea ratings (0 to 10 scale) each minute during incremental exercise on the cycle ergometer. At Visit 2 patients rated dyspnea during production of submaximal exercise for 10 min at two intensities. RESULTS: Peak oxygen consumption (VO2) was 13.9 +/- 3.2 mL.kg-1.min-1. At visit 2 VO2 was stable, but dyspnea ratings increased slightly. Dyspnea ratings (2.0 +/- 1.2) during submaximal exercise were higher than during incremental exercise (1.1 +/- 0.7) at 55 +/- 8% of peak VO2 (P = 0.02) but were similar (4.3 +/- 1.5 vs 3.9 +/- 1.5) at 77 +/- 8% of peak VO2 (P = 0.40). CONCLUSIONS: In patients with COPD, dyspnea ratings were similar during steady state compared with equivalent levels of incremental exercise at a "high" intensity, but were slightly higher at the "low" exercise intensity. These data support the potential use of dyspnea ratings obtained during incremental exercise as a target for exercise training in patients with respiratory disease.

Salmeterol reduces dyspnea and improves lung function in patients with COPD.

STUDY OBJECTIVE: To investigate the short-term effects of inhaled salmeterol on the perception of dyspnea and lung function in patients with COPD. DESIGN: Double-blind, crossover, randomized trial comparing inhaled salmeterol and inhaled placebo over 4 h. SETTING: Pulmonary function laboratory at university medical center. PATIENTS: Sixteen patients with symptomatic COPD and at least 200-mL increase in FEV1 after inhalation of two puffs (180 microg) of albuterol. INTERVENTIONS: Visit 1 was used for familiarization. At visits 2 and 3 (2 to 3 days apart), patients inhaled either two puffs of salmeterol (42 microg) or placebo. MEASUREMENTS AND RESULTS: Lung function and dyspnea were measured at 0.5, 2, and 4 h after inhalation of the study medication. Dyspnea was measured by the -5 to +5 category scale at rest and by the 0 to 10 category-ratio scale while breathing through inspiratory resistances of 5, 15, and 30 cm H20/L/s. Age was 66+/-8 years (mean+/-SD). FEV1 was 0.97+/-0.331 (51+/-13% predicted). There were significantly higher values for FEV1 and FVC (at all time periods) and lower values for functional residual capacity (at all time periods) and residual volume (at 4 h) with salmeterol than with placebo. There were significantly lower dyspnea ratings on the -5 to +5 category scale (p=0.03 at 2 h and p=0.02 at 4 h) and for the mean dyspnea scores during resistive breathing with salmeterol compared with placebo (p=0.002). CONCLUSIONS: Inhaled salmeterol reduced dyspnea, increased airflow, and reduced hyperinflation over 4 h in patients with symptomatic COPD.

Descriptors of breathlessness in cardiorespiratory diseases.

The purposes of this study were: to examine the decriptors of breathlessness chosen by a large sample of patients with cardiorespiratory disease; to determine test-retest reliability of a patient's selection of the descriptors; and to assess whether a patient's recall of the experience of breathlessness is the same as that provoked by physical activity. Questionnaire data were collected at an initial visit for patients who complained of breathlessness and at a second visit in a subgroup of patients. A total of 218 patients who sought medical care for difficulty breathing due to one of seven different conditions were recruited from an outpatient pulmonary disease clinic at a university medical center. Patients selected statements that described qualities of breathlessness from a 15-item questionnaire and completed pulmonary function tests. At a subsequent visit (4 to 15 d later) a subgroup of 16 patients with chronic obstructive pulmonary disease (COPD) repeated the questionnaire at rest (to assess reliability) and after walking in a hallway to provoke a moderate intensity of breathlessness (to compare recall with direct experiences). The relationship among descriptors was evaluated by cluster analysis. The "work/effort" cluster was common for all diagnoses. Each condition was characterized by more than one cluster except COPD. Each diagnosis was associated with a unique set of dusters (e.g., asthma with "work/effort" and "tight," interstitial lung disease with "work/effort" and "rapid" breathing). Percent agreement for all descriptors selected at Visits 1 and 2 (recall) was 79% (r = 0.82; p = 0.001). Percent agreement at Visit 2 between descriptors for recall and for breathlessness provoked by walking was 68% (r = 0.69; p = 0.004). We conclude that patients with different cardiorespiratory conditions experience distinct qualities of breathlessness. Patients' recall of their sensations of breathlessness is reliable and comparable to dyspnea with walking. Employing a questionnaire containing descriptors of breathlessness may help to establish a specific diagnosis and to identify mechanisms whereby a specific intervention relieves dyspnea.

Locomotor-respiratory coupling develops in novice female rowers with training.

The purpose of this study was to investigate the hypothesis that locomotor-respiratory coupling (LRC), or entrainment of breathing, develops in the sport of rowing as a result of training. We prospectively evaluated exercise responses over an 8 month training session (October to May) in 12 female subjects who were members of the Dartmouth College novice rowing team. Progressive, incremental exercise testing was performed on the variable-resistance rowing ergometer (Concept II, Morrisville, VT). To relate the pattern of breathing to the mechanics of rowing, the catch and finish of each rowing stroke during the last 30 s of each minute of exercise were marked on the strip chart paper that recorded inspiratory flow measured by using a heated pneumotachograph. Age was 18 +/- 1 yr (mean +/- SE); weight was 67.5 +/- 2.1 kg. Peak oxygen consumption (VO2) increased by 10% from October (40.8 +/- 0.6 ml.kg.min-1) to May (P less than 0.001). Chi-square goodness-of-fit analysis was used to assess whether the proportion of inspirations occurring in each of four quadrants of circle plots representing repetitive rowing strokes exercise intensities of 100 watts (W) and peak VO2 were random or corresponded to a regular pattern of breathing. Although 5 of 12 subjects demonstrated LRC at exercise of 100 W in October, there was no significant change at this submaximal intensity over the training season. Only 2 of 12 subjects showed LRC at peak exercise in October, but there was a significant increase (P = 0.003) in the number of subjects who entrained breathing in Jan (10/12) and May (8/12).(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of breathlessness during exercise in asthmatics. Predictor variables, reliability, and responsiveness.

The purpose of this study was to determine the predictor variables for breathlessness and to investigate the criteria of reliability and responsiveness for measuring breathlessness during progressive, incremental exercise on the cycle ergometer. We studied a heterogeneous group of patients with stable asthma (mean +/- SEM age, 46 +/- 4 yr) for four visits at weekly intervals. Predictor variables were determined at the first visit. Nine independent physiologic variables were obtained at each minute during exercise; the Borg rating of breathlessness (range 0 to 10) was used as the dependent variable. The regression model relating the physiologic parameters to the Borg rating of breathlessness was highly significant (model F = 43.4; p = 0.0001). Backward elimination selected the strongest predictors of the Borg rating: peak inspiratory flow (VI); tidal volume (VT)/FVC; frequency of respiration (f); and peak inspiratory mouth pressures (Pm). These four variables explained 63% of the variance in the rating of dyspnea. Each of the four variables exhibited a linear relationship with the Borg rating. Test-retest reliability was assessed by comparing results at the first and second visits. Individual slopes (except for VT/FVC) and intercepts for the four predictor variables versus Borg ratings were highly reliable. The slope for work intensity (watts) and Borg ratings, but not the intercept, was highly reliable. Responsiveness was evaluated by randomly administering inhaled methacholine or inhaled metaproterenol, alternately, at the third and fourth visits to induce acute changes in lung function before exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of clinical dyspnea ratings and psychophysical measurements of respiratory sensation in obstructive airway disease.

To investigate the hypothesis that clinical methods and psychophysical testing provide different information about breathlessness, we compared dyspnea ratings from a modified Medical Research Council (MRC) scale, the Oxygen-Cost Diagram (OCD), and the Baseline Dyspnea Index (BDI) with the perceived magnitude of added loads in 24 patients with obstructive airway disease (OAD) who experienced dyspnea on exertion. Age of the patients was 55.8 +/- 13.7 yr (mean +/- SD), FEV1 was 1.77 +/- 0.81 L, and FEV1/FVC ratio was 52.6 +/- 10.5%. Dyspnea ratings were obtained for each clinical method by 2 independent observers; estimates of the magnitude of 5 resistive loads (10 to 85 cm H2O/L/s) were obtained using the Borg category scale (0 to 10). For comparative purposes, 12 age-matched (48.9 +/- 13.5 yr) healthy subjects were also studied. Clinical ratings of dyspnea obtained in patients for MRC (range, 0 to 4), OCD (range, 23 to 98), and BDI (range, 0.5 to 12.0) were all highly interrelated (rs = 0.79, -0.83, and -0.71; p less than 0.001 for all comparisons). Exponents of the psychophysical power function for resistive breathing loads were similar for patients with OAD (0.57 +/- 0.27) and control subjects (0.63 +/- 0.18) (p = NS). Clinical dyspnea scores were significantly correlated with both FEV1 and FVC; however, neither dyspnea ratings nor lung function were significantly related to the exponent for added breathing loads in the patient group. These comparisons indicate that in patients with symptomatic OAD, clinical methods for rating dyspnea are interrelated and are correlated with lung function, but are independent of perception of resistive breathing loads.(ABSTRACT TRUNCATED AT 250 WORDS)