Simplified detection of dynamic hyperinflation.

STUDY OBJECTIVE To detect dynamic hyperinflation by comparing reduction in inspiratory capacity (IC) during both paced hyperventilation and cycle ergometry in patients with moderate-to-severe COPD, studied before and after acute bronchodilation. METHODS IC and FEV(1) were measured before and after metronome-paced hyperventilation at twice the resting respiratory rate for 20 s in 16 patients with COPD before and after 54 microg aerosolized ipratropium bromide (IB). We also studied the same 16 patients before and after administration of 54 microg aerosolized IB during symptom-limited incremental cycle ergometry when the final respiratory rate was also twice the resting rate. RESULTS Resting IC was 2.23 +/- 0.53 L (mean +/- SD), and the mean decrease in IC from baseline was 0.36 +/- 0.25 L after exercise (p < 0.001), and not significantly different (p = 0.64) from mean decrease in IC of 0.40 +/- 0.29 L following hyperventilation. Results following hyperventilation and exercise were similar after bronchodilator. The mean difference for decrease of IC between hyperventilation and exercise was 0.138 L (95% confidence interval, - 0.347 to 0.622; r = 0.66, p = 0.006). The decrease in FEV(1) was 0.01 +/- 0.13 L after exercise and 0.06 +/- 0.18 L after hyperventilation. Separately, baseline and peak end-expiratory and end-inspiratory lung volumes were similar with hyperventilation vs exercise both before and after bronchodilator. CONCLUSION Both metronome-paced hyperventilation and incremental cycle ergometry, when resting respiratory rate was doubled, provoked similar significant decrease in IC, even after administration of 54 microg aerosolized IB. The noninvasive simplicity of hyperventilation for 20 s provides a clinically useful screening surrogate to monitor changes in IC following exercise.

[1]  S. Hurd,et al.  Global Strategy for the Diagnosis, Management and Prevention of COPD: 2003 update , 2003, European Respiratory Journal.

[2]  R. Pellegrino,et al.  Inspiratory capacity and decrease in lung hyperinflation with albuterol in COPD. , 2002, Chest.

[3]  D. O’Donnell,et al.  Dynamic hyperinflation and exercise intolerance in chronic obstructive pulmonary disease. , 2001, American journal of respiratory and critical care medicine.

[4]  B. Celli,et al.  Inspiratory capacity, dynamic hyperinflation, breathlessness, and exercise performance during the 6-minute-walk test in chronic obstructive pulmonary disease. , 2001, American journal of respiratory and critical care medicine.

[5]  N. Zamel,et al.  Unsuspected pseudophysiologic emphysema in chronic persistent asthma. , 2000, American journal of respiratory and critical care medicine.

[6]  H. Magnussen,et al.  Factor analysis of changes in dyspnea and lung function parameters after bronchodilation in chronic obstructive pulmonary disease. , 2000, American journal of respiratory and critical care medicine.

[7]  M. Tobin,et al.  Does inhaled albuterol improve diaphragmatic contractility in patients with chronic obstructive pulmonary disease? , 1999, American journal of respiratory and critical care medicine.

[8]  D. O’Donnell,et al.  Spirometric correlates of improvement in exercise performance after anticholinergic therapy in chronic obstructive pulmonary disease. , 1999, American journal of respiratory and critical care medicine.

[9]  D. O’Donnell,et al.  Measurement of symptoms, lung hyperinflation, and endurance during exercise in chronic obstructive pulmonary disease. , 1998, American journal of respiratory and critical care medicine.

[10]  P. Śliwiński,et al.  Reliability of inspiratory capacity for estimating end-expiratory lung volume changes during exercise in patients with chronic obstructive pulmonary disease. , 1997, American journal of respiratory and critical care medicine.

[11]  D. O’Donnell,et al.  Qualitative aspects of exertional breathlessness in chronic airflow limitation: pathophysiologic mechanisms. , 1997, American journal of respiratory and critical care medicine.

[12]  M. Belman,et al.  Inhaled bronchodilators reduce dynamic hyperinflation during exercise in patients with chronic obstructive pulmonary disease. , 1996, American journal of respiratory and critical care medicine.

[13]  N. Jones,et al.  Muscle strength, symptom intensity, and exercise capacity in patients with cardiorespiratory disorders. , 1995, American journal of respiratory and critical care medicine.

[14]  D. O’Donnell,et al.  Exertional breathlessness in patients with chronic airflow limitation. The role of lung hyperinflation. , 1993, The American review of respiratory disease.

[15]  A. Miller,et al.  Lung function testing: selection of reference values and interpretative strategies. , 1992, The American review of respiratory disease.

[16]  J. Dempsey,et al.  Regulation of end-expiratory lung volume during exercise. , 1988, Journal of applied physiology.

[17]  G. Guyatt,et al.  Acute response to bronchodilator. An imperfect guide for bronchodilator therapy in chronic airflow limitation. , 1988, Archives of internal medicine.

[18]  L. A. Engel,et al.  Chest wall mechanics during exercise in patients with severe chronic air-flow obstruction. , 1984, The American review of respiratory disease.

[19]  N. Jones,et al.  Pulmonary mechanics during exercise in subjects with chronic airflow obstruction. , 1980, Journal of applied physiology: respiratory, environmental and exercise physiology.