Proportional assist ventilation as an aid to exercise training in severe chronic obstructive pulmonary disease

Background: The effects of providing ventilatory assistance to patients with severe chronic obstructive pulmonary disease (COPD) during a high intensity outpatient cycle exercise programme were examined. Methods: Nineteen patients (17 men) with severe COPD (mean (SD) forced expiratory volume in 1 second (FEV1) 27 (7)% predicted) underwent a 6 week supervised outpatient cycle exercise programme. Ten patients were randomised to exercise with ventilatory assistance using proportional assist ventilation (PAV) and nine (two women) to exercise unaided. Before and after training patients performed a maximal symptom limited incremental cycle test to determine peak work rate (Wpeak) followed by a constant work rate (CWR) test at 70% of Wpeak achieved in the baseline incremental test. Minute ventilation (Ve), heart rate, and arterialised venous plasma lactate concentration [La+] were measured before and after each test. Results: Mean training intensity (Wt/Wpeak) at 6 weeks was 15.2% (95% CI 3.2 to 27.1) higher in the group that used ventilatory assistance (p=0.016). Peak work rate after training was 18.4% (95% CI 6.4 to 30.5) higher (p=0.005) in the assisted group (p=0.09). [La+] at an identical workload after training was reduced by 30% (95% CI 16 to 44) in the assisted group (p=0.002 compared with baseline) and by 11% (95% CI –7 to 31) (p=0.08 compared with baseline) in the unassisted group (mean difference 18.4% (95% CI 3.3 to 40), p=0.09). A significant inverse relationship was found between reduction in plasma lactate concentration (ΔL) at an equivalent workload after training during the CWR test and Wt/Wpeak achieved during the last week of training (r=–0.7, p=0.0006). Conclusions: PAV enables a higher intensity of training in patients with severe COPD, leading to greater improvements in maximum exercise capacity with evidence of true physiological adaptation.

[1]  R. Zeballos,et al.  Clinical exercise testing. , 2001, Clinics in chest medicine.

[2]  F. Maltais,et al.  Proportional assist ventilation may improve exercise performance in severe chronic obstructive pulmonary disease. , 2001, Journal of cardiopulmonary rehabilitation.

[3]  N. Ambrosino,et al.  Nasal proportional assist ventilation unloads the inspiratory muscles of stable patients with hypercapnia due to COPD. , 2000, The European respiratory journal.

[4]  M. Polkey,et al.  Inspiratory pressure support prolongs exercise induced lactataemia in severe COPD , 2000, Thorax.

[5]  N. Payne,et al.  Results at 1 year of outpatient multidisciplinary pulmonary rehabilitation: a randomised controlled trial , 2000, The Lancet.

[6]  J. Barberà,et al.  Effects of endurance training on skeletal muscle bioenergetics in chronic obstructive pulmonary disease. , 1999, American journal of respiratory and critical care medicine.

[7]  F. Maltais,et al.  Altered expression of myosin heavy chain in the vastus lateralis muscle in patients with COPD. , 1999, The European respiratory journal.

[8]  D. Poole,et al.  Evidence of skeletal muscle metabolic reserve during whole body exercise in patients with chronic obstructive pulmonary disease. , 1999, American journal of respiratory and critical care medicine.

[9]  F. Maltais,et al.  Metabolic and hemodynamic responses of lower limb during exercise in patients with COPD. , 1998, Journal of applied physiology.

[10]  N. Ambrosino,et al.  Effects of proportional assist ventilation on exercise tolerance in COPD patients with chronic hypercapnia. , 1998, The European respiratory journal.

[11]  R. Casaburi,et al.  Physiologic benefits of exercise training in rehabilitation of patients with severe chronic obstructive pulmonary disease. , 1997, American journal of respiratory and critical care medicine.

[12]  J. Dempsey,et al.  Respiratory muscle work compromises leg blood flow during maximal exercise. , 1997, Journal of applied physiology.

[13]  R. Goldstein,et al.  Proportional assist ventilation and exercise tolerance in subjects with COPD. , 1997, Chest.

[14]  F. Maltais,et al.  Intensity of training and physiologic adaptation in patients with chronic obstructive pulmonary disease. , 1997, American journal of respiratory and critical care medicine.

[15]  M. Polkey,et al.  Inspiratory pressure support reduces slowing of inspiratory muscle relaxation rate during exhaustive treadmill walking in severe COPD. , 1996, American journal of respiratory and critical care medicine.

[16]  F. Maltais,et al.  Skeletal muscle adaptation to endurance training in patients with chronic obstructive pulmonary disease. , 1996, American journal of respiratory and critical care medicine.

[17]  F. Maltais,et al.  Oxidative capacity of the skeletal muscle and lactic acid kinetics during exercise in normal subjects and in patients with COPD. , 1996, American journal of respiratory and critical care medicine.

[18]  F. Maltais,et al.  Pressure support reduces inspiratory effort and dyspnea during exercise in chronic airflow obstruction. , 1995, American journal of respiratory and critical care medicine.

[19]  G. Guyatt,et al.  Randomised controlled trial of respiratory rehabilitation , 1994, The Lancet.

[20]  S. Keilty,et al.  Effect of inspiratory pressure support on exercise tolerance and breathlessness in patients with severe stable chronic obstructive pulmonary disease. , 1994, Thorax.

[21]  G. Gibson.  Standardised lung function testing. , 1993, The European respiratory journal.

[22]  N. Jones,et al.  Exercise capacity and ventilatory, circulatory, and symptom limitation in patients with chronic airflow limitation. , 1992, The American review of respiratory disease.

[23]  M. Belman.  Factors limiting exercise performance in lung disease. Ventilatory insufficiency. , 1992, Chest.

[24]  R. Casaburi,et al.  Principles of exercise training. , 1992, Chest.

[25]  M. Nishimura,et al.  Hypoplastic left heart syndrome associated with congenital right-sided diaphragmatic hernia and omphalocele. , 1992, Chest.

[26]  M. Younes.  Proportional assist ventilation, a new approach to ventilatory support. Theory. , 1992, The American review of respiratory disease.

[27]  M. Belman,et al.  Reductions in exercise lactic acidosis and ventilation as a result of exercise training in patients with obstructive lung disease. , 1991, The American review of respiratory disease.

[28]  B. Saltin,et al.  Skeletal Muscle Adaptability: Significance for Metabolism and Performance , 1985 .

[29]  G. Borg.  Psychophysical bases of perceived exertion. , 1982, Medicine and science in sports and exercise.

[30]  J. Dempsey,et al.  Estimation of arterial PO2, PCO2, pH, and lactate from arterialized venous blood. , 1972, Journal of applied physiology.

[31]  T. Clark,et al.  The ventilatory capacity of patients with chronic airways obstruction. , 1969, Clinical science.