Patient-Ventilator Interactions in Chronic Obstructive Pulmonary Diseases (COPD) Under Non-Invasive Ventilation

Patient-Ventilator Interactions in Chronic Obstructive Pulmonary Diseases (COPD) Under Non-Invasive Ventilation

Non-invasive ventilation (NIV) in severe hypercapnic Chronic Obstructive Pulmonary Diseases (COPD) may be associated - during sleep - with recurrent episodes of patient ventilatory asynchrony, which in turn may affect quality of sleep, efficacy of ventilation and comfort of nocturnal NIV.Polysomnography (PSG) under NIV is necessary to detect these events. Adjusting ventilator settings according to respiratory events detected by PSG with NIV may improve quality of sleep, efficacy of ventilation and comfort of nocturnal NIV.

Patients under NIV for hypercapnic COPD have several reasons to develop patient-ventilatory asynchrony: delayed cycling, and insufficient expiratory time may induce progressive dynamic hyperinflation, and increase intrinsic positive end-expiratory pressure (PEEPi); too high levels of pressure support may also contribute to dynamic hyperinflation. Increase in PEEPi is associated with two respiratory events: unrewarded inspiratory efforts, and auto-triggering. Our hypotheses are: 1/that these events occur frequently in COPD under NIV and that they are not detected by medical history or usual monitoring tools (SpO2; PtcCO2); 2/ that they can be easily detected by polysomnography; 3/ that simple adjustments of ventilator parameters aiming to reduce dynamic hyperinflation and unrewarded inspiratory efforts may improve efficacy of ventilation, quality of sleep and comfort of treatment. The present study compares the results of two consecutive sleep studies: 1.PSG under NIV in severe stable COPD under "usual ventilator settings" with 2.PSG under NIV after adapting ventilator settings to results of initial PSG.

Non-invasive ventilation, Chronic Obstructive Pulmonary Disease, Patient-ventilator synchronisation, Sleep study, Polysomnography

Decrease in pressure support, increase in respiratory back-up rate, increase in expiratory positive airway pressure (EPAP) to counteract effect of PEEPi, and adjustment of cycling (at higher percentage of peak inspiratory flow)

Visual analogic scale (VAS) of morning dyspnea, and questionnaire evaluating 8 items of comfort of ventilation (Janssens JP et al; Impact of volume targeting on efficacy of bi-level non-invasive ventilation and sleep in obesity-hypoventilation; Respir Med 2009 Feb;103(2):165-72)

Analysis of leaks, estimated ventilation, SpO2, TcPCO2, sleep structure, and patient-ventilatory synchronisation and comparison with data under "usual settings" for ventilator

Inclusion Criteria: COPD, with chronic hypercapnic respiratory failure, treated by NIV, in stable clinical condition, aged above 18 years Exclusion Criteria: Unstable clinical condition

Janssens JP, Metzger M, Sforza E. Impact of volume targeting on efficacy of bi-level non-invasive ventilation and sleep in obesity-hypoventilation. Respir Med. 2009 Feb;103(2):165-72. doi: 10.1016/j.rmed.2008.03.013. Epub 2008 Jun 24.

Adler D, Perrig S, Takahashi H, Espa F, Rodenstein D, Pepin JL, Janssens JP. Polysomnography in stable COPD under non-invasive ventilation to reduce patient-ventilator asynchrony and morning breathlessness. Sleep Breath. 2012 Dec;16(4):1081-90. doi: 10.1007/s11325-011-0605-y. Epub 2011 Nov 4.