Search

Daniel S Majorski,1 Jens C Callegari,1 Sarah B Schwarz,1 Friederike S Magnet,1 Rodion Majorski,2 Jan H Storre,3,4 Claudia Schmoor,5 Wolfram Windisch1 1Cologne Merheim Hospital, Department of Pneumology, Kliniken der Stadt Köln gGmbH, Witten/Herdecke University, Cologne, Germany; 2Department of Neurology and Neurophysiology, Helios Hospital Wuppertal, Witten/Herdecke University, Wuppertal, Germany; 3Praxis Pneumologie Solln, Munich, Germany; 4Department of Pneumology, University Medical Hospital, Freiburg, Germany; 5Clinical Trials Unit, Medical Center – University Medical Hospital, Freiburg, GermanyCorrespondence: Wolfram WindischDepartment of Pneumology, Cologne Merheim Hospital, Kliniken der Stadt Köln gGmbH, Witten/Herdecke University, Faculty of Health/School of Medicine, Ostmerheimer Strasse 200, Köln, D-51109, GermanyEmail windischw@kliniken-koeln.dePurpose: The impact of oronasal and nasal masks on the quality of nocturnal non-invasive ventilation (NIV) needs to be clarified. This trial was designed to compare the impact of oronasal and nasal masks on the objective quality and subjective acceptance of nocturnal NIV in COPD-patients.Patients and Methods: In a randomized crossover trial, 30 COPD-patients with well-established high-intensity NIV (mean inspiratory/expiratory positive airway pressure 26± 3/5± 1 cmH2O, mean respiratory back-up rate 17± 1/min) were ventilated for two consecutive nights on oronasal and nasal masks, respectively.Results: Full polysomnography, nocturnal blood gas measurements, and subjective assessments were performed. There was a tendency towards improved sleep efficiency (primary outcome) when an oronasal mask was worn (+9.9%; 95% CI:-0.2%-20.0%; P=0.054). Sleep stages 3/4 were favored by the oronasal mask (+12.7%; 95% CI: 6.0%-19.3%; P=< 0.001). Subjective assessments were comparable with the exception of items related to leakage (P< 0.05 in favor of nasal masks). The mean transcutaneous PCO2 value for oronasal masks (47.7± 7.4 mmHg) was comparable to that of nasal masks (48.9± 6.6 mmHg) (P=0.11). There was considerable diversity amongst individual patients in terms of sleep quality and gas exchange following mask exchange. Subjective mask preference was not associated with sleep quality, but with nocturnal dyspnea. Over 40% of patients subsequently switched to the mask that they were not previously accustomed to.Conclusion: In general, oronasal and nasal masks are each similarly capable of successfully delivering NIV in COPD-patients. However, the individual response to different interfaces is extremely heterogeneous, while subjective mask preference is independent from objective measures, but associated with dyspnea.Trial Registration: German Clinical Trials Registry (DRKS00007741).Keywords: respiratory insufficiency, sleep, masks, dyspnea

Jan Hendrik Storre,1,2 Jens Callegari,3 Friederike Sophie Magnet,3 Sarah Bettina Schwarz,3 Marieke Leontine Duiverman,4,5 Peter Jan Wijkstra,4,5 Wolfram Windisch3 1Department of Intensive Care, Sleep Medicine and Mechanical Ventilation, Asklepios Fachkliniken Munich-Gauting, Gauting, Germany; 2Department of Pneumology, University Medical Hospital, Freiburg, Germany; 3Department of Pneumology, Cologne Merheim Hospital, Kliniken der Stadt Köln gGmbH Witten/Herdecke University, Faculty of Health/School of Medicine, Cologne, Germany; 4Department of Pulmonary Diseases, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands; 5Groningen Research Institute of Asthma and COPD (GRIAC), University of Groningen, Groningen, the Netherlands Abstract: Long-term or home mechanical noninvasive ventilation (Home-NIV) has become a well-established form of therapy over the last few decades for chronic hypercapnic COPD patients in European countries. However, meta-analyses and clinical guidelines do not recommend Home-NIV for COPD patients on a routine basis. In particular, there is ongoing debate about Home-NIV in chronic hypercapnic COPD regarding the overall effects, the most favorable treatment strategy, the selection of eligible patients, and the time point at which it is prescribed. The current review focuses on specific aspects of patient selection and discusses the various scientific as well as clinical-guided perspectives on Home-NIV in patients suffering from chronic hypercapnic COPD. In addition, special attention will be given to the topic of ventilator settings and interfaces. Keywords: exacerbation, pulmonary emphysema, hypercapnia, mechanical ventilation, respiratory insufficiency

Friederike Sophie Magnet,1 Daniel Sebastian Majorski,1 Jens Callegari,1 Sarah Bettina Schwarz,1 Claudia Schmoor,2 Wolfram Windisch,1 Jan Hendrik Storre3,4 1Department of Pneumology, Cologne Merheim Hospital, Kliniken der Stadt Köln gGmbH Witten/Herdecke University, Faculty of Health/School of Medicine, Cologne, Germany; 2Clinical Trials Unit, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; 3Department of Intensive Care, Sleep Medicine and Mechanical Ventilation, Asklepios Fachkliniken Munich-Gauting, Gauting, Germany; 4Department of Pneumology, University Medical Hospital, Freiburg, Germany Purpose: To compare arterial (PaO2) with capillary (PcO2) partial pressure of oxygen in hypoxemic COPD patients because capillary blood gas analysis (CBG) is increasingly being used as an alternative to arterial blood gas analysis (ABG) in a non-intensive care unit setting, although the agreement between PcO2 and PaO2 has not been evaluated in hypoxemic COPD patients.Patients and methods: Bland–Altman comparison of PaO2 and PcO2 served as the primary outcome parameter if PcO2 values were ≤60 mmHg and the secondary outcome parameter if PcO2 values were ≤55 mmHg. Pain associated with the measurements was assessed using a 100-mm visual analog scale.Results: One hundred and two PaO2/PcO2 measurement pairs were obtained. For PcO2 values ≤60 mmHg, the mean difference between PaO2 and PcO2 was 5.99±6.05 mmHg (limits of agreement: -5.88 to 17.85 mmHg). For PcO2 values ≤55 mmHg (n=73), the mean difference was 5.33±5.52 mmHg (limits of agreement: -5.48 to 16.15 mmHg). If PaO2 ≤55 (≤60) mmHg was set as the cut-off value, in 20.6% (30.4%) of all patients, long-term oxygen therapy have been unnecessarily prescribed if only PcO2 would have been assessed. ABG was rated as more painful compared with CBG.Conclusions: PcO2 does not adequately reflect PaO2 in hypoxemic COPD patients, which can lead to a relevant number of unnecessary long-term oxygen therapy prescriptions. Keywords: blood gas analysis, COPD, respiratory insufficiency, hypoxemia

Jens Callegari,1 Friederike Sophie Magnet,1 Steven Taubner,1 Melanie Berger,2 Sarah Bettina Schwarz,1 Wolfram Windisch,1 Jan Hendrik Storre3,4 1Department of Pneumology, Cologne-Merheim Hospital, Kliniken der Stadt Koeln, Witten/Herdecke University Hospital, 2Department of Pneumology, Malteser Hospital St Hildegardis, Cologne, 3Department of Pneumology, University Medical Hospital, Freiburg, 4Department of Intensive Care, Sleep Medicine and Mechanical Ventilation, Asklepios Fachkliniken Munich-Gauting, Gauting, Germany Introduction: The establishment of high-intensity (HI) noninvasive ventilation (NIV) that targets elevated PaCO2 has led to an increase in the use of long-term NIV to treat patients with chronic hypercapnic COPD. However, the role of the ventilation interface, especially in more aggressive ventilation strategies, has not been systematically assessed.Methods: Ventilator settings and NIV compliance were assessed in this prospective cross-sectional monocentric cohort study of COPD patients with pre-existing NIV. Daytime ­arterialized blood gas analyses and lung function testing were also performed. The primary end point was the distribution among study patients of interfaces (full-face masks [FFMs] vs nasal masks [NMs]) in a real-life setting.Results: The majority of the 123 patients studied used an FFM (77%), while 23% used an NM. Ventilation settings were as follows: mean ± standard deviation (SD) inspiratory positive airway pressure (IPAP) was 23.2±4.6 mbar and mean ± SD breathing rate was 16.7±2.4/minute. Pressure support ventilation (PSV) mode was used in 52.8% of patients, while assisted pressure-controlled ventilation (aPCV) was used in 47.2% of patients. Higher IPAP levels were associated with an increased use of FFMs (IPAP 25 mbar: 84%). Mean compliance was 6.5 hours/day, with no differences between FFM (6.4 hours/day) and NM (6.7 hours/day) users. PaCO2 assessment of ventilation quality revealed comparable results among patients with FFMs or NMs.Conclusion: This real-life trial identified the FFM as the predominantly used interface in COPD patients undergoing long-term NIV. The increased application of FFMs is, therefore, likely to be influenced by higher IPAP levels, which form part of the basis for successful application of HI-NIV in clinical practice. Keywords: compliance, home mechanical ventilation, interfaces, masks, pressure support, ventilation modes

Background: Although high-intensity noninvasive positive pressure ventilation (HI-NPPV) is superior to low-intensity noninvasive positive pressure ventilation (LI-NPPV) in controlling nocturnal hypoventilation in stable hypercapnic patients with COPD, it produces higher amounts of air leakage, which, in turn, could impair sleep quality. Therefore, the present study assessed the difference in sleep quality during HI-NPPV and LI-NPPV.Methods: A randomized, controlled, crossover trial comparing sleep quality during HI-NPPV (mean inspiratory positive airway pressure 29 ± 4 mbar) and LI-NPPV (mean inspiratory positive airway pressure 14 mbar) was performed in 17 stable hypercapnic patients with COPD who were already familiar with HI-NPPV.Results: Thirteen patients (mean FEV(1) 27% ± 11% predicted) completed the trial; four patients refused to sleep under LI-NPPV. There was no significant difference in sleep quality between the treatment groups (all P > .05), with a mean difference of -3.0% (95% CI, -10.0 to 3.9; P = .36) in the primary outcome, namely non-rapid eye movement sleep stages 3 and 4. However, nocturnal Paco(2) was lower during HI-NPPV compared with LI-NPPV, with a mean difference of -6.4 mm Hg (95% CI, -10.9 to -1.8; P = .01).Conclusions: In patients with COPD, high inspiratory pressures used with long-term HI-NPPV produce acceptable sleep quality that is no worse than that produced by lower inspiratory pressures, which are more traditionally applied in conjunction with LI-NPPV. In addition, higher pressures are more successful in maintaining sufficient alveolar ventilation compared with low pressures. Thus, HI-NPPV is a very promising new approach, but still requires large, longer-term trials to determine the impact on outcomes such as exacerbation rates and longevity.Trial Registry: German Clinical Trials Register (DRKS); No.: DRKS00000520; URL: www.drks.de. [ABSTRACT FROM AUTHOR]

BACKGROUND: To assess the efficacy of transcutaneous Pco2 (Ptcco2) measurements for monitoring alveolar ventilation in patients requiring noninvasive positive-pressure ventilation (NPPV). METHODS: In a prospective study on method agreement pairs of Paco2 and Ptcco2 (SenTec Digital Monitor; SenTec AG; Therwil, Switzerland), measurements were performed every 10 min during the establishment of NPPV over a 4-h period in 10 patients (8 patients with COPD) presenting with acute-on-chronic hypercapnic respiratory failure, thus providing 250 pairs of measurement. RESULTS: Mean (+/- SD) Paco2 decreased from 67.2 +/- 11.9 mm Hg (Ptcco2, 65.5 +/- 13.9 mm Hg) to 54.6 +/- 8.8 mm Hg (Ptcco2, 47.8 +/- 8.8 mm Hg), and mean pH increased from 7.36 +/- 0.03 to 7.44 +/- 0.04. Following Ptcco2 assessment, Ptcco2 in the ensuing 2-min period was the strongest predictor for Paco2 compared to Ptcco2 in the ensuing 5-min period and to real-time measurements. Ptcco2 was highly correlated with Paco2 (r = 0.916; p < 0.001), as determined by linear regression analysis. The mean difference between Paco2 and Ptcco2 was 4.6 mm Hg, and the limits of agreement (bias +/- 1.96 SDs) ranged from -3.9 to 13.2 mm Hg, following the Bland and Altman analysis. Retrospective drift correction produced an even higher correlation (r = 0.956; p < 0.001) with lower limits of agreement (-1.7 to 7.5 mm Hg). CONCLUSIONS: Ptcco2 measurements provide a sensitive, continuous, and noninvasive method for monitoring alveolar ventilation in patients who are receiving short-term NPPV therapy. Drift correction of Ptcco2 measurements improves the accuracy of Ptcco2 monitoring compared to the 'gold standard' Paco2 assessment. A lag time of approximately 2 min is present for reliable Ptcco2 values compared to Paco2 values. However, individual variance between Paco2 and Ptcco2 cannot be excluded. Trial registration: www.uniklinik-freiburg.de/zks/live/uklregister/Oeffentlich.html Identifier:UKF001271. [ABSTRACT FROM AUTHOR]

BACKGROUND: Average volume-assured pressure support (AVAPS) has been introduced as a new additional mode for a bilevel pressure ventilation (BPV) device (BiPAP; Respironics; Murrysville, PA), but studies on the physiologic and clinical effects have not yet been performed. There is a particular need to better define the most efficient ventilatory treatment modality for patients with obesity hypoventilation syndrome (OHS). METHODS: In OHS patients who did not respond to therapy with continuous positive airway pressure, the effects of BPV with the spontaneous/timed (S/T) ventilation mode with and without AVAPS over 6 weeks on ventilation pattern, gas exchange, sleep quality, and health-related quality of life (HRQL) assessed by the severe respiratory insufficiency questionnaire (SRI) were prospectively investigated in a randomized crossover trial. RESULTS: Ten patients (mean [+/- SD] age, 53.5 +/- 11.7 years; mean body mass index, 41.6 +/- 12.1 kg/m2; mean FEV1/FVC ratio, 79.4 +/- 6.5%; mean transcutaneous P(CO2) [PtcCO2], 58 +/- 12 mm Hg) were studied. PtcCO2 nonsignificantly decreased during nocturnal BPV-S/T by -5.6 +/- 11.8 mm Hg (95% confidence interval [CI], -14.7 to 3.4 mm Hg; p = 0.188), but significantly decreased during BPV-S/T-AVAPS by -12.6 +/- 12.2 mm Hg (95% CI, -22.0 to -3.2 mm Hg; p = 0.015). Pneumotachographic measurements revealed a higher individual variance of peak inspiratory pressure (p < 0.001) and a trend for lower leak volumes but also for higher tidal volumes during BPV-S/T-AVAPS. The SRI summary scale score improved from 63 +/- 15 to 78 +/- 14 during BPV-S/T (p = 0.004) and to 76 +/- 16 during BPV-S/T-AVAPS (p = 0.014). Sleep quality and oxygen saturation also comparably improved following BPV-S/T and BPV-S/T-AVAPS. CONCLUSION: BPV-S/T substantially improved oxygenation, sleep quality, and HRQL in patients with OHS. AVAPS provided additional benefits on ventilation quality, thus resulting in a more efficient decrease of PtcCO2. However, this did not provide further clinical benefits regarding sleep quality and HRQL. [ABSTRACT FROM AUTHOR]

COPD is the most common reason for hypercapnia. However, it is - by far - not the only reason. In fact, numerous neuromuscular disorders (not only ALS) as well as restrictive thoracic disorders do also lead to clinically highly relevant hypercapnia. Early diagnosis of hypercapnic ventilatory failure usually takes place at nighttime. NIV devices work with a periodic interplay of alternating IPAP and EPAP which results in a ventilation of the lungs, thereby elimination CO 2 to treat hypercapnic respiratory failure. Firstline settings for a NIV therapy to treat "stable hypercapnia" are as follows: Pressure Support Ventilation Modus, EPAP 5 cm H 2 O, IPAP 15 cm H 2 O, Back Up rate 15/Minute. The overall goal of NIV treatment is a successful reduction in CO 2 . This can be achieved by changing the following variables of the ventilator settings: increase in IPAP ± increase in back up respiratory rate ± use of assisted pressure controlled ventilation mode (APCV)-., Competing Interests: Erklärung zu finanziellen Interessen Forschungsförderung erhalten: ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Honorar/geldwerten Vorteil für Referententätigkeit erhalten: ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Bezahlter Berater/interner Schulungsreferent/Gehaltsempfänger: ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Patent/Geschäftsanteile/Aktien (Autor/Partner, Ehepartner, Kinder) an im Bereich der Medizin aktiven Firma: nein; Patent/Geschäftsanteile/Aktien (Autor/Partner, Ehepartner, Kinder) an zu Sponsoren dieser Fortbildung bzw. durch die Fortbildung in ihren Geschäftsinteressen berührten Firma: nein Erklärung zu nichtfinanziellen Interessen Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Background: Non-invasive ventilation (NIV) has been shown to be the most appropriate therapy for COPD patients with chronic respiratory failure. While physiological parameters and long-term outcome frequently serve as primary outcomes, very few studies have primarily addressed the impact of NIV initiation on sleep quality in COPD., Methods: This single-center prospective cohort study comprised NIV-naïve patients with COPD. All patients underwent polysomnographic evaluation both at baseline and at 3 months follow-up, accompanied by the assessment of health-related quality of life (HRQL) using the Severe Respiratory Insufficiency Questionnaire (SRI) and the Epworth Sleepiness Scale (ESS). A subgroup evaluation was performed to address the impact of comorbid obstructive sleep apnea syndrome (OSAS)., Results: Forty-six patients were enrolled and twenty-five patients completed the follow-up period (66.7 ± 7.4 years). NIV resulted in an increase in slow-wave sleep (+2% (-3.5/7.5), p = 0.465) and rapid eye movement sleep (+2.2% (-1.0/5.4), p = 0.174), although no statistical significance could be detected. ESS (-1.7(-3.6/0.1), p = 0.066) also showed a positive trend. Significant improvements in the Respiratory Disturbance Index (RDI) (-12.6(-23.7/-1.5), p = 0.027), lung function parameters, transcutaneous PCO 2 and the SRI summary scale (4.5(0.9/8), p = 0.016) were observed., Conclusion: NIV therapy does not decrease sleep quality and is even capable of improving HRQL, transcutaneous PaCO 2 , daytime sleepiness and RDI, and the latter especially holds true for patients with comorbid OSAS.

COPD is the most common reason for hypercapnia. However, it is -by far- not the only reason. In fact, numerous neuromuscular disorders (not only ALS) as well as restrictive thoracic disorders do also lead to clinically highly relevant hypercapnia. Early diagnosis of hypercapnic ventilatory failure usually takes place at nighttime. NIV devices work with a periodic interplay of alternating IPAP and EPAP which results in a ventilation of the lungs, thereby elimination CO2 to treat hypercapnic respiratory failure. Firstline settings for a NIV therapy to treat "stable hypercapnia" are as follows: Pressure Support Ventilation Modus, EPAP 5 cmH2O, IPAP 15 cmH2O, Back Up rate 15/Minute. The overall goal of NIV treatment is a successful reduction in CO2. This can be achieved by changing the following variables of the ventilator settings: increase in IPAP ± increase in back up respiratory rate ± use of assisted pressure controlled ventilation mode (APCV)., Competing Interests: Erklärung zu finanziellen InteressenForschungsförderung erhalten: Ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Honorar/geldwerten Vorteil für Referententätigkeit erhalten: Ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Bezahlter Berater/interner Schulungsreferent/Gehaltsempfänger: Ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Patent/Geschäftsanteile/Aktien (Autor/Partner, Ehepartner, Kinder) an Firma (Sponsor der Veranstaltung): Nein; Patent/Geschäftsanteile/Aktien (Autor/Partner, Ehepartner, Kinder) an Firma (Nicht-Sponsor der Veranstaltung): Nein.Erklärung zu nichtfinanziellen InteressenDie Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Background: Patient-ventilator synchronization during non-invasive ventilation (NIV) can be assessed by visual inspection of flow and pressure waveforms but it remains time consuming and there is a large inter-rater variability, even among expert physicians. SyncSmart™ software developed by Breas Medical (Mölnycke, Sweden) provides an automatic detection and scoring of patient-ventilator asynchrony to help physicians in their daily clinical practice. This study was designed to assess performance of the automatic scoring by the SyncSmart software using expert clinicians as a reference in patient with chronic respiratory failure receiving NIV. Methods: From nine patients, 20 min data sets were analyzed automatically by SyncSmart software and reviewed by nine expert physicians who were asked to score auto-triggering (AT), double-triggering (DT), and ineffective efforts (IE). The study procedure was similar to the one commonly used for validating the automatic sleep scoring technique. For each patient, the asynchrony index was computed by automatic scoring and each expert, respectively. Considering successively each expert scoring as a reference, sensitivity, specificity, positive predictive value (PPV), κ-coefficients, and agreement were calculated. Results: The asynchrony index assessed by SynSmart was not significantly different from the one assessed by the experts (18.9 ± 17.7 vs. 12.8 ± 9.4, p = 0.19). When compared to an expert, the sensitivity and specificity provided by SyncSmart for DT, AT, and IE were significantly greater than those provided by an expert when compared to another expert. Conclusions: SyncSmart software is able to score asynchrony events within the inter-rater variability. When the breathing frequency is not too high (<24), it therefore provides a reliable assessment of patient-ventilator asynchrony; AT is over detected otherwise., Competing Interests: ML reports personal fees for lectures from Philips and Resmed. JA is part time employee at Hamilton Medical. He has received advisory honorarium from Breas Medical and ResMed. He has received honorarium for lecturing from Philips. AC has received fees for lecturing and roundtable meetings from Philips, Breas and Resmed. MC has received advisory honorarium from Breas Medical and ResMed. She has received honorarium for lecturing from, Philips, ResMed, Breas and MPR. CL has received fees for consulting from Breas Medical. JS reports grants and personal fees for lectures from Heinen und Löwenstein and VitalAire, grants, personal fees for lectures and non-financial support for meeting attendance from Vivisol GmbH, grants from Weinmann Deutschland, personal fees for consultancy/advisory board work from Breas Medical, during the conduct of the study; personal fees for consultancy and lectures, and non-financial support for meeting attendance from Boehringer Ingelheim Pharma, personal fees for consultancy and lectures from SenTec AG, Keller Medical GmbH, Linde Deutschland and Santis GmbH, outside the submitted work. NH has received unrestricted research grants from Philips, Philips-Respironics, B&D Electromedical, Breas and Fisher-Paykel. He has has received fees for lecturing and roundtable meetings from Philips, Philips-Respironics, B&D Electromedical, Breas and Fisher-Paykel. SN has received fees for lecturing and roundtable meetings from Philips, Breas and Resmed. He is on the advisory board for Breas and Philips. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Letellier, Lujan, Arnal, Carlucci, Chatwin, Ergan, Kampelmacher, Storre, Hart, Gonzalez-Bermejo and Nava.)

Background: The spontaneous breathing trial (SBT) is a well-established diagnostic test for predicting extubation failure in intubated intensive care unit (ICU) patients. However, the SBT has not been evaluated in a specific cohort of tracheostomized patients in whom weaning is prolonged and ultimately unsuccessful., Objective: The aim of the trial was to investigate the relevance of SBT failure criteria in chronic respiratory failure subjects undergoing long-term invasive home mechanical ventilation following tracheostomy and weaning failure., Methods: Measurement of all established failure criteria including pneumotachygraphical assessment of the rapid shallow breathing index (RSBI) took place during an SBT. The decision to continue spontaneous breathing was based on failure criteria as well as the subjective willingness of the patient., Results: Fifteen subjects with a median age of 58 years (interquartile range [IQR] 44-74) were studied; 10 with COPD, 4 with neuromuscular diseases and 1 with both. Twelve subjects met the SBT failure criteria within 30 min, but one third of these subjects were still able to continue with spontaneous breathing. In contrast, 3 subjects could not be weaned despite the SBT being successful. An increased RSBI was the most frequently observed SBT failure criterion (57% of all SBT). However, the SBT varied substantially in individual subjects who were able to sustain spontaneous breathing, despite having reached the cut-off for SBT failure., Conclusion: The SBT was of low predictive value regarding spontaneous breathing ability in chronic respiratory failure subjects with prolonged, unsuccessful weaning.

Background and Objective: Obesity hypoventilation syndrome (OHS) can be treated with either continuous positive airway pressure (CPAP) or non-invasive ventilation (NIV) therapy; the device choice has important economic and operational implications., Methods: This multicentre interventional trial investigated the safety and short-term efficacy of switching stable OHS patients who were on successful NIV therapy for ≥3 months to CPAP therapy. Patients underwent an autotitrating CPAP night under polysomnography (PSG); if the ensuing parameters were acceptable, they were sent home on a fixed CPAP for a 4-6-week period. It was hypothesized that blood gas analysis, PSG parameters and lung function tests would remain unchanged., Results: A total of 42 OHS patients were recruited, of whom 37 patients were switched to CPAP therapy. All patients had a history of severe obstructive sleep apnoea syndrome; chronic obstructive pulmonary disease (COPD) (Global Initiative for Obstructive Lung Disease (GOLD) I/II) was present in 52%. Regarding the primary outcome, 30 of 42 patients (71%, 95% CI: 55-84%) maintained daytime partial pressure of carbon dioxide (PaCO 2 ) levels ≤45 mm Hg after the home CPAP period. There was no further impairment in quality of life, sleep parameters or lung function. Interestingly, 24 patients (65%) preferred CPAP as their long-term therapy, despite the high pressure levels used (mean: 13.8 ± 1.8 mbar). After the CPAP period, 7 of 37 patients were categorized as CPAP failure, albeit only due to mild hypercapnia (mean: 47.9 ± 2.7 mm Hg)., Conclusion: It is feasible to switch most stable OHS patients from NIV to CPAP therapy, a step that could significantly reduce health-related costs. The auto-adjusted CPAP device, used in combination with the analysis of the PSG and capnometry, is a valid titration method in OHS patients., (© 2019 Asian Pacific Society of Respirology.)