The effects of long-term noninvasive ventilation in hypercapnic COPD patients: a randomized controlled pilot study

Abstract

IntroductionNoninvasive ventilation (NIV) is a well-established treatment for acute-on- chronic respiratory failure in hypercapnic COPD patients. Less is known about the effects of a long-term treatment with NIV in hypercapnic COPD patients and about the factors that may predict response in terms of improved oxygenation and lowered CO2 retention.MethodsIn this study, we randomized 15 patients to a routine pharmacological treatment (n = 5, age 66 [standard deviation ± 6] years, FEV1 30.5 [±5.1] %pred, PaO2 65 [±6] mmHg, PaCO2 52.4 [±6.0] mmHg) or to a routine treatment and NIV (using the Synchrony BiPAP device [Respironics, Inc, Murrsville, PA]) (n = 10, age 65 [±7] years, FEV1 29.5 [±9.0] %pred, PaO2 59 [±13] mmHg, PaCO2 55.4 [±7.7] mmHg) for 6 months. We looked at arterial blood gasses, lung function parameters and performed a low-dose computed tomography of the thorax, which was later used for segmentation (providing lobe and airway volumes, iVlobe and iVaw) and post-processing with computer methods (providing airway resistance, iRaw) giving overall a functional image of the separate airways and lobes.ResultsIn both groups there was a nonsignificant change in FEV1 (NIV group 29.5 [9.0] to 38.5 [14.6] %pred, control group 30.5 [5.1] to 36.8 [8.7] mmHg). PaCO2 dropped significantly only in the NIV group (NIV: 55.4 [7.7] → 44.5 [4.70], P = 0.0076; control: 52.4 [6.0] → 47.6 [8.2], NS). Patients actively treated with NIV developed a more inhomogeneous redistribution of mass flow than control patients. Subsequent analysis indicated that in NIV-treated patients that improve their blood gases, mass flow was also redistributed towards areas with higher vessel density and less emphysema, indicating that flow was redistributed towards areas with better perfusion. There was a highly significant correlation between the % increase in mass flow towards lobes with a blood vessel density of >9% and the increase in PaO2. Improved ventilation–perfusion match and recruitment of previously occluded small airways can explain the improvement in blood gases.ConclusionWe can conclude that in hypercapnic COPD patients treated with long-term NIV over 6 months, a mass flow redistribution occurs, providing a better ventilation–perfusion match and hence better blood gases and lung function. Control patients improve homogeneously in iVaw and iRaw, without improvement in gas exchange since there is no improved ventilation/perfusion ratio or increased alveolar ventilation. These differences in response can be detected through functional imaging, which gives a more detailed report on regional lung volumes and resistances than classical lung function tests do. Possibly only patients with localized small airway disease are good candidates for long-term NIV treatment. To confirm this and to see if better arterial blood gases also lead to better health related quality of life and longer survival, we have to study a larger population.

The cost-effectiveness of domiciliary non-invasive ventilation in patients with end-stage chronic obstructive pulmonary disease: a systematic review and economic evaluation

“…Forced expiratory volume in 1 second was measured in two further studies; however, in one 82 no post-treatment data were presented (it was stated that there were no significant changes in either arm), and in the other 91 the data presented for SDs appeared to be incorrect. The RCT by Köhnlein et al…”

“…Results from only one study 79,80 with a stable population were adjusted for baseline (this study had more intensive usual care in both arms). Three further studies (in a stable population) measured PaO 2 but were not included: two 74,76 found no significant difference and the other 91 appeared to have errors in the reported SD.…”

“…Eight RCTs 32,77,79,82,83,91,[99][100][101] in a stable population and one 92 in a post-hospital population reported 6MWD at baseline and at follow-up times between 3 and 24 months. There was one statistically significant result for the stable population (in favour of NIV, adjusted result), but, overall, the results for the stable population are inconsistent in terms of direction of effect, which may be a reflection of differences in …”

End-tidal arterial CO2 partial pressure gradient in patients with severe hypercapnia undergoing noninvasive ventilation

“…The device has been successfully used to improve exercise tolerance in COPD patients by increasing respiratory muscle strength, 38 and its long term use provides a better ventilation-perfusion match, and better blood gases and lung function through a mass-flow redistribution. 39 The efficacy of BiPAP has been evaluated in acute settings as well: in acute exacerbation of COPD, its use leads to an increase of arterial oxygen partial pressure (PaO 2 ), a reduction of intubation rate, an amelioration of respiratory and other vital parameters, and a reduction in in-hospital mortality; 3,4 as regards acute cardiogenic pulmonary edema, the combination of inspiratory assistance with expiratory positive airway pressure can effectively alleviate respiratory distress, and as a consequence bilevel ventilation is considered more effective than continuous positive airway pressure (CPAP). 5,16 Systematic reviews have shown the benefit of BiPAP in the management of acute cardiogenic pulmonary edema, with reduction in the need for invasive mechanical ventilation and reduction of mortality.…”

Multi-scale computational models of the airways to unravel the pathophysiological mechanisms in asthma and chronic obstructive pulmonary disease (AirPROM)

“…Following the changes in these image-based outcome parameters provides a strong indication of the efficiency and response to therapies ( figure 3). In previous studies, this concept has been applied to long-acting b 2 -agonists (LABAs) [32], a combination of a LABA and an inhaled corticosteroid [30], a short-acting anticholinergic, a short-acting b 2 -agonist [31] and non-invasive ventilation [33]. The concept has been validated using gamma scintigraphy [34], single-photon emission computed tomography [35] and HP MRI [36].…”