Effects of proportional assist ventilation on exercise tolerance in COPD patients with chronic hypercapnia (original) (raw)
Related papers
CHEST Journal, 2007
Background: Breathlessness is the most common symptom limiting exercise in patients with chronic obstructive pulmonary disease (COPD). Exercise training can improve both exercise tolerance and health status in these patients, intensity of exercise being of key importance. Nevertheless, in these patients extreme breathlessness and/or peripheral muscle fatigue may prevent patients from reaching higher levels of intensity. Study objective: This study was to determine whether inspiratory pressure support (IPS) applied during sub maximal exercise could enable individuals with severe but stable COPD to increase their exercise tolerance. Participants: Twelve subjects with severe stable COPD (mean (SD): age = 63(8.2) years; FEV 1 = 0.89(0.42) L (34)% predicted; FEV 1 /FVC = 0.31(0.07) only nine subjects completed the study. Intervention: Each subject completed ten sessions of cycling at 25%-50% of their maximum power without NIVS and another ten sessions using NIVS. Measurements and results: Dyspnea was measured using Borg scale. Subjects reached high levels of dyspnea 4.7 (1.81) during the sessions without NIVS vs low levels of dyspnea during the sessions using NIVS 1.3 (0.6). Exercise time during the sessions without NIVS and with NIVS was 19.37 (3.4) and 33.75 (9.5) min, respectively. Maximal workload during the sessions without NIVS and with NIVS was 27 (3.7) and 50 (10.5) watt, respectively. Conclusion: We conclude that IPS delivered by nasal mask can improve exercise tolerance and dyspnea in stable severe COPD patients and hence this mode of ventilatory support may be useful in respiratory rehabilitation programs.
Thorax, 2002
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 (FEV 1) 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 (∆L) 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.
Physiotherapy Research International, 2009
Background. Non-invasive ventilation (NIV) during exercise in patients with chronic obstructive pulmonary disease (COPD) has been shown to increase exercise time and intensity. Feasibly then, NIV during pulmonary rehabilitation will enhance post-rehabilitation training effects. The purpose of this review is to systematically consider and critique the literature concerning the effects of NIV, when used during an exercise programme in COPD patients on exercise tolerance. Method. An electronic literature search was completed and the reference lists of the articles that fi tted the following inclusion criteria were screened. Studies that used any mode of NIV during an exercise programme with a primary outcome measure focusing on exercise tolerance and were written after the year 2000 to refl ect current practice. Studies that were not written in English or had been included in previous literature reviews were excluded. The studies were then critically appraised and assigned a level of evidence based upon Scottish Intercollegiate Guidelines Network. Results. Twenty-eight articles were screened, of which six fi tted the inclusion criteria. The methodological quality ranged from level 1− to 1+. All but one study by demonstrated a statistically signifi cant improvement in exercise tolerance with the addition of some form of NIV during pulmonary rehabilitation. The benefi ts may be greater in patients with more severe airway obstruction as determined by Forced Expiration Volume (FEV), (%pred). Conclusion. This review would suggest that NIV may allow an increased exercise intensity and duration during pulmonary rehabilitation in patients with moderate to very severe COPD, (according to the American Thoracic Society guidelines), resulting in a greater training effect and a prolonged exercise capacity. Further research looking at long-term follow-up is recommended.
Respirology, 2010
Background and objective: Proportional assist ventilation (PAV) has been proposed as a more physiological modality of non-invasive ventilation, thereby reducing the potential for deleterious cardio-circulatory effects during exercise, in patients with COPD. We therefore evaluated whether PAV modulates the kinetic and ‘steady-state’ haemodynamic responses to exercise in patients with moderate-to-severe COPD.Methods: Twenty patients underwent constant-load (75–80% peak work rate) cycle ergometer exercise testing to the limit of tolerance (Tlim), while receiving PAV or breathing spontaneously. Stroke volume (SV), heart rate (HR) and cardiac output (CO) were monitored by impedance cardiography.Results: Compared with unassisted breathing, PAV increased Tlim in 8/20 patients (median improvement 113% (range 8 to 212) vs −20% (range −40 to −9)). PAV had no significant effects on ‘steady-state’ haemodynamic responses either in patients with or those without increased Tlim (P > 0.05). However, at the onset of exercise, SV kinetics were slowed with PAV, in 13/15 patients with analysable data. HR dynamics remained unaltered or failed to accelerate sufficiently in nine of these patients, thereby slowing CO kinetics (T1/2 61 s (range 81–30) vs 89 s (range 100–47)). These deleterious effects were not, however, associated with PAV-induced changes in Tlim (P > 0.05).Conclusions: PAV slowed the SV and CO kinetics at the onset of high-intensity exercise in selected patients with moderate-to-severe COPD. However, these adverse effects of PAV disappeared during the stable phase of exercise, and were not related to the ergogenic potential of PAV in this patient population.
Physiological and clinical relevance of exercise ventilatory efficiency in COPD
The European respiratory journal, 2017
Exercise ventilation (V'E) relative to carbon dioxide output (V'CO2 ) is particularly relevant to patients limited by the respiratory system, e.g. those with chronic obstructive pulmonary disease (COPD). High V'E-V'CO2 (poor ventilatory efficiency) has been found to be a key physiological abnormality in symptomatic patients with largely preserved forced expiratory volume in 1 s (FEV1). Establishing an association between high V'E-V'CO2 and exertional dyspnoea in mild COPD provides evidence that exercise intolerance is not a mere consequence of detraining. As the disease evolves, poor ventilatory efficiency might help explaining "out-of-proportion" breathlessness (to FEV1 impairment). Regardless, disease severity, cardiocirculatory co-morbidities such as heart failure and pulmonary hypertension have been found to increase V'E-V'CO2 In fact, a high V'E-V'CO2 has been found to be a powerful predictor of poor outcome in lung resection su...
Respirology, 2010
Background and objective: Proportional assist ventilation (PAV) has been proposed as a more physiological modality of non-invasive ventilation, thereby reducing the potential for deleterious cardio-circulatory effects during exercise, in patients with COPD. We therefore evaluated whether PAV modulates the kinetic and 'steady-state' haemodynamic responses to exercise in patients with moderate-to-severe COPD. Methods: Twenty patients underwent constant-load (75-80% peak work rate) cycle ergometer exercise testing to the limit of tolerance (Tlim), while receiving PAV or breathing spontaneously. Stroke volume (SV), heart rate (HR) and cardiac output (CO) were monitored by impedance cardiography. Results: Compared with unassisted breathing, PAV increased Tlim in 8/20 patients (median improvement 113% (range 8 to 212) vs -20% (range -40 to -9)). PAV had no significant effects on 'steady-state' haemodynamic responses either in patients with or those without increased Tlim (P > 0.05). However, at the onset of exercise, SV kinetics were slowed with PAV, in 13/15 patients with analysable data. HR dynamics remained unaltered or failed to accelerate sufficiently in nine of these patients, thereby slowing CO kinetics (T1/2 61 s (range 81-30) vs 89 s (range 100-47)). These deleterious effects were not, however, associated with PAVinduced changes in Tlim (P > 0.05). Conclusions: PAV slowed the SV and CO kinetics at the onset of high-intensity exercise in selected patients with moderate-to-severe COPD. However, these adverse effects of PAV disappeared during the stable phase of exercise, and were not related to the ergogenic potential of PAV in this patient population.
Respiratory Medicine, 2002
Different modalities of assisted ventilation improve breathlessness and exercise tolerance in patients with chronic obstructive pulmonarydisease (COPD).The aim ofthis study was to evaluate the effects ofthe addition of assisted ventilation during exercise training on the outcome of a structured pulmonary rehabilitation programme (PRP) in COPD patients.Thirty-three male patients with stable COPD (mean (SD) forced expiratory volume in1s (FEV 1 ) 44 (16) % pred), without chronic ventilatory failure, undergoing a 6 -week multidisciplinary outpatient PRP including exercise training, were randomised to training during either mask proportional assist ventilation (PAV:18 patients) or spontaneous breathing (SB: 15 patients). Assessment included exercise tolerance, dyspnoea, leg fatigue, and health-related quality of life (HRQL). Five out of18 patients (28%) in the PAV group dropped out due to lack of compliance with the equipment.Both groups showed significant post-PRP improvements in exercise tolerance (peak workrate difference: 20 (95% CI 2.4--37.6) and 14 (3.8% CI to 24.2) W in PAV and SB group, respectively), dyspnoea and leg fatigue, but not in HRQL, without any significant difference between groups. It is concluded that with the modality and in the patients assessed in this study, assisted ventilation during training sessions included in a multidisciplinary PRP, was not well tolerated by all patients and gave no additional physiological benefit in comparison with exercise training alone. r 2002
Respirology (Carlton, Vic.), 2018
Background and objective: Patients with chronic obstructive pulmonary disease (COPD) and chronic hypercapnic respiratory failure (CHRF) characteristically have exercise intolerance and limitations in performing conventional training. Therefore, the aim of this study was to investigate the acute effects of noninvasive ventilation (NIV) as a supportive tool during exercise in CHRF. Methods: Two cycle endurance tests (CET) at 60% of the peak work rate were performed. Patients were randomly assigned to cycle in two conditions: (i) high-pressure NIV (mean inspiratory positive airway pressure: 27 AE 3 cm H 2 O) along with oxygen supplementation or (ii) control: oxygen-use only. Transcutaneously measured partial pressure of carbon dioxide (TcPCO 2), oxygen saturation and heart rate were continuously recorded. Muscle oxygen availability of intercostal and vastus lateralis muscle was measured during exercise by near-infrared spectroscopy (NIRS). Results: A total of 20 patients with CHRF (forced expiratory volume in 1 s (FEV 1): 19 AE 4% predicted, partial pressure of oxygen (PaO 2): 55 AE 9 mm Hg, partial pressure of carbon dioxide (PaCO 2): 51 AE 7 mm Hg) were recruited in a randomized cross-over trial. On NIV, COPD patients increased cycle endurance time by 39% compared to oxygen-use only (663 AE 360 vs 477 AE 249 s, P = 0.013). On NIV, TcPCO 2 was significantly lower at rest (44.9 AE 6.2 vs 50.7 AE 6.6 mm Hg, P < 0.001) and at isotime (50.0 AE 5.5 vs 56.1 AE 6.2 mm Hg, P < 0.001). Oxygen availability in the intercostal muscles remained relatively constant with NIV compared to oxygen-use only. Although patients cycled longer using NIV, a lower increase in exertional dyspnoea at the end of CET (median increase in Borg-dyspnoea: 2 vs 4, P = 0.003) was reported. Conclusion: NIV with high pressures as add-on to oxygen supplementation increases cycle endurance time, mitigates exertional dyspnoea and limits exerciseinduced hypercapnia in COPD patients with CHRF.
Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD
Respiratory Care, 2012
BACKGROUND: Ventilatory inefficiency increases ventilatory demand; corresponds to an abnormal increase in the ratio of minute ventilation (V E) to CO 2 production (V CO 2); represents increased dead space, deregulation of respiratory control, and early lactic threshold; and is associated with expiratory flow limitation that enhances dynamic hyperinflation and may limit exercise capacity. OBJECTIVE: To evaluate the influence of ventilatory inefficiency over exercise capacity in COPD patients. METHODS: Prospective study of 35 COPD subjects with different levels of severity, in whom cardiopulmonary stress test was performed. Ventilatory inefficiency was represented by the V E /V CO 2 relation. Its influence over maximal oxygen consumption (V O 2 max), power (W), and ventilatory threshold was evaluated. Surrogate parameters of cardiac function, like oxygen pulse (V O 2 /heart rate) and circulatory power (%V O 2 max ؋ peak systolic pressure), were also evaluated. RESULTS: Cardiopulmonary stress test was stopped due to dyspnea with elevated V E and marked reduction of breathing reserve. A severe increase in V E /V CO 2 (mean ؎ SD 35.9 ؎ 5.6), a decrease of V O 2 max (mean ؎ SD 75.2 ؎ 20%), and a decrease of W (mean ؎ SD 68.6 ؎ 23.3%) were demonstrated. Twenty-eight patients presented dynamic hyperinflation. Linear regression showed a reduction of 2.04% on V O 2 max (P < .001), 2.6% on W (P < .001), 1% on V O 2 /heart rate (P ؍ .049), and 322.7 units on circulatory power (P ؍ .02) per each unit of increment in V E /V CO 2 , respectively. CONCLUSIONS: Ventilatory inefficiency correlates with a reduction in exercise capacity in COPD patients. Including this parameter in the evaluation of exercise limitation in this patient population may mean a contribution toward the understanding of its pathophysiology.