Early outcomes following the implementation of a specialised pleural disease service.

BACKGROUND: Pleural effusion is a common cause of hospitalisation and a poor prognostic marker that is associated with morbidity and mortality. The evaluation and management of pleural effusion may be performed more effectively by a specialised pleural disease service (SPDS). AIMS: To evaluate the impact of a SPDS established in 2017 at a 400-bed metropolitan hospital in Victoria, Australia. METHODS: A retrospective observational study was undertaken comparing outcomes of individuals with pleural effusions. People with pleural effusion were identified using administrative data. Two 12-month time periods were compared, 2016 (Period 1, before SPDS) and 2018 (Period 2, after SPDS). RESULTS: Period 1 had n = 76 and Period 2 had n = 96 individuals with pleural effusion receiving intervention. Age (69.8 ± 17.6 vs 71.8 ± 15.8), gender and Charlson Comorbidity Index (4.9 ± 2.8 vs 5.4 ± 3.0) were similar across both periods. Utilisation of point-of-care ultrasound for pleural procedures increased from Period 1 to 2, 57.3-85.7% (P < 0.001). There was a reduction in median days from admission to intervention (3.8-2.1 days, P = 0.048) and pleural-related re-intervention rate (32% vs 19%, P = 0.032). Pleural fluid testing was more consistent with recommendations (16.8% vs 43.2%, P < 0.001). Overall, there was no difference in the median length of stay (7.9 vs 6.4 days, P = 0.23), pleural-related readmissions (11% vs 16%, P = 0.69) or mortality (17.1% vs 15.6%, P = 0.79). Procedural complications were similar between the two periods. CONCLUSIONS: The introduction of a SPDS was associated with increased point-of-care ultrasound utilisation for pleural procedures, shorter delays to intervention and improved standardisation of tests on pleural fluid.

Missed diagnosis or misdiagnosis: how often do hospitalised patients with a diagnosis of chronic obstructive pulmonary disease have spirometry that supports the diagnosis?

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is one of the most common clinical diagnoses among hospital inpatients. Diagnosis requires the demonstration of post-bronchodilator airflow obstruction. However, it is uncertain how often spirometry results are available at the time a diagnostic label of COPD is applied. AIMS: To identify how frequently spirometry results were available following an inpatient admission with a clinical diagnosis of COPD, and to determine how often the available spirometry results supported a clinical diagnosis of COPD. Inhaler prescription, at discharge, was also evaluated to determine one of the potential implications of diagnostic inaccuracy. METHODS: A single-centre retrospective observational study was undertaken at a 400-bed metropolitan health service between October 2016 and March 2018. RESULTS: A total of 2239 inpatient separations occurred in 1469 individuals who had a clinical diagnosis of COPD during the study. Spirometry results were not available in 43.6% (n = 641) of those with a diagnosis of COPD. A further 19.7% (n = 289) had spirometry results available at the time of admission that did not demonstrate fixed airflow obstruction. The available prescribing data (n = 443) demonstrated that inhaled medications were prescribed in a similar pattern, regardless of the availability of spirometry or whether the results supported a clinical diagnosis of COPD. CONCLUSIONS: Inpatients with a clinical diagnosis of COPD frequently did not have supportive spirometry results that confirmed the diagnosis or had results inconsistent with COPD. Misdiagnosis and inappropriate prescribing require further attention to improve the quality of care in this setting.

Thunderstorm asthma in seasonal allergic rhinitis: The TAISAR study.

BACKGROUND: Asthma epidemics associated with thunderstorms have had catastrophic effects on individuals and emergency services. Seasonal allergic rhinitis (SAR) is present in the vast majority of people who develop thunderstorm asthma (TA), but there is little evidence regarding risk factors for TA among the SAR population. OBJECTIVE: We sought to identify risk factors for a history of TA and hospital presentation in a cohort of individuals with SAR. METHODS: This multicenter study recruited adults from Melbourne, Australia, with a past diagnosis of TA and/or self-reported SAR. Clinical information, spirometry results, white blood cell count, ryegrass pollen-specific (RGP-sp) IgE concentration, and fractional exhaled nitric oxide were measured to identify risk factors for a history of TA in individuals with SAR. RESULTS: From a total of 228 individuals with SAR, 35% (80 of 228) reported SAR only (the I-SAR group), 37% (84 of 228) reported TA symptoms but had not attended hospital for treatment (the O-TA group), and 28% (64 of 228) had presented to the hospital for TA (the H-TA group). All patients in the H-TA group reported a previous asthma diagnosis. Logistic regression analysis of factors associated with O-TA and H-TA indicated that lower FEV1 value and an Asthma Control Questionnaire score higher than 1.5 were associated with H-TA. Higher blood RGP-sp IgE concentration, eosinophil counts, and fractional exhaled nitric oxide level were significantly associated with both O-TA and H-TA. Receiver operating curve analysis showed an RGP-sp IgE concentration higher than 10.1 kU/L and a prebronchodilator FEV1 value of 90% or lower to be biomarkers of increased H-TA risk. CONCLUSION: Clinical tests can identify risk of a history of TA in individuals with SAR and thereby inform patient-specific treatment recommendations.

Diaphragm dysfunction: a comprehensive review from diagnosis to management.

Although the diaphragm represents a critical component of the respiratory pump, the clinical presentations of diaphragm dysfunction are often non-specific and can be mistaken for other more common causes of dyspnoea. While acute bilateral diaphragm dysfunction typically presents dramatically, progressive diaphragm dysfunction associated with neuromuscular disorders and unilateral hemidiaphragm dysfunction may be identified incidentally or by recognising subtle associated symptoms. Diaphragm dysfunction should be considered in individuals with unexplained dyspnoea, restrictive respiratory function tests or abnormal diaphragm position on plain chest imaging. A higher index of suspicion should occur for individuals with profound orthopnoea, those who have undergone procedures in proximity to the phrenic nerve(s) or those with co-morbid conditions that are associated with diaphragm dysfunction, particularly neuromuscular disorders. A systematic approach to the evaluation of diaphragm function using non-invasive diagnostic techniques such as respiratory function testing and diaphragm imaging can often confirm a diagnosis. Neurophysiological assessment may confirm diaphragm dysfunction and assist in identifying an underlying cause. Identifying those with or at risk of respiratory failure can allow institution of respiratory support, while specific cases may also benefit from surgical plication or phrenic nerve pacing techniques.

Randomised controlled trial of polysomnographic titration of noninvasive ventilation.

Noninvasive ventilation (NIV) settings determined during wakefulness may produce patient-ventilator asynchrony (PVA) during sleep, causing sleep disruption and limiting tolerance. This study investigated whether NIV titrated with polysomnography (PSG) is associated with less PVA and sleep disruption than therapy titrated during daytime alone.Treatment-naive individuals referred for NIV were randomised to control (daytime titration followed by sham polysomnographic titration) or PSG (daytime titration followed by polysomnographic titration) groups. Primary outcomes were PVA and arousal indices on PSG at 10 weeks. Secondary outcomes included adherence, gas exchange, symptoms and health-related quality of life (HRQoL).In total, 60 participants were randomised. Most (88.3%) had a neuromuscular disorder and respiratory muscle weakness but minor derangements in daytime arterial blood gases. PVA events were less frequent in those undergoing polysomnographic titration (median (interquartile range (IQR)): PSG 25.7 (12-68) events·h-1 versus control 41.0 (28-182) events·h-1; p=0.046), but arousals were not significantly different (median (IQR): PSG 11.4 (9-19) arousals·h-1 versus control 14.6 (11-19) arousals·h-1; p=0.258). Overall adherence was not different except in those with poor early adherence (<4 h·day-1) who increased their use after polysomnographic titration (mean difference: PSG 95 (95% CI 29-161) min·day-1 versus control -23 (95% CI -86-39) min·day-1; p=0.01). Arterial carbon dioxide tension, somnolence and sleep quality improved in both groups. There were no differences in nocturnal gas exchange or overall measures of HRQoL.NIV titrated with PSG is associated with less PVA but not less sleep disruption when compared with therapy titrated during daytime alone.

Framing of mobility items: a source of poor agreement between preference-based health-related quality of life instruments in a population of individuals receiving assisted ventilation.

PURPOSE: To explore the influence of descriptive differences in items evaluating mobility on index scores generated from two generic preference-based health-related quality of life (HRQoL) instruments. METHODS: The study examined cross-sectional data from a postal survey of individuals receiving assisted ventilation in two state/province-wide home mechanical ventilation services, one in British Columbia, Canada and the other in Victoria, Australia. The Assessment of Quality of Life 8-dimension (AQoL-8D) and the EQ-5D-5L were included in the data collection. Graphical illustrations, descriptive statistics, and measures of agreement [intraclass correlation coefficients (ICCs) and Bland-Altman plots] were examined using index scores derived from both instruments. Analyses were performed on the full sample as well as subgroups defined according to respondents' self-reported ability to walk. RESULTS: Of 868 individuals receiving assisted ventilation, 481 (55.4%) completed the questionnaire. Mean index scores were 0.581 (AQoL-8D) and 0.566 (EQ-5D-5L) with 'moderate' agreement demonstrated between the two instruments (ICC = 0.642). One hundred fifty-nine (33.1%) reported level 5 ('I am unable to walk about') on the EQ-5D-5L Mobility item. The walking status of respondents had a marked influence on the comparability of index scores, with a larger mean difference (0.206) and 'slight' agreement (ICC = 0.386) observed when the non-ambulant subgroup was evaluated separately. CONCLUSIONS: This study provides further evidence that between-measure discrepancies between preference-based HRQoL instruments are related in part to the framing of mobility-related items. Longitudinal studies are necessary to determine the responsiveness of preference-based HRQoL instruments in cohorts that include non-ambulant individuals.

Physician-performed chest ultrasound: progress and future directions.

BACKGROUND: Pleural ultrasound guidance reduces complications of pleural procedures, and lung ultrasound can diagnose the cause of acute respiratory failure. Yet as recently as 5 years ago, many respiratory physicians lacked sufficient access, training and expertise to perform a chest ultrasound. AIMS: This study examines whether progress has been achieved in chest ultrasound amongst respiratory physicians in Australia and New Zealand. METHODS: We conducted a web-based chest ultrasound survey of adult respiratory physicians across Australia and New Zealand. We also surveyed advanced trainees. RESULTS: The response rate was 38% among respiratory physicians. Between 2011 and 2016, access to bedside ultrasound increased from 53 to 90%. The proportion arranging ultrasound guidance for pleural aspiration rose from 66 to 95%. The proportion demonstrably competent in pleural ultrasound increased from 4 to 21%. In 2016, 67% of physicians and 80% of advanced trainees reported available workplace supervision for ultrasound training. Use of lung ultrasound to diagnose acute pulmonary oedema and consolidation improved from 2011 but remained low at 25 and 20% respectively. CONCLUSION: These results establish pleural ultrasound guidance for pleural procedures as the standard of care in our region. However, lung ultrasound remains underutilised. Ultrasound training can and should be incorporated into specialist respiratory training.

NIV@Home: a pilot randomized controlled trial of in-home noninvasive ventilation initiation compared to a single-day admission model.

Objective: Noninvasive ventilation (NIV) is the primary treatment for respiratory insufficiency in neuromuscular disease. NIV implementation is usually conducted within hospitals; however, in-home implementation with intensive follow-up is an effective alternative. This pilot study aimed to assess model feasibility, acceptability, and NIV usage at 12-weeks after a single visit in-home implementation of NIV with remote monitoring follow-up (NIV@Home) compared to an in-hospital day admission NIV initiation plus planned polysomnography (Usual care). Methods: A single-blinded randomized controlled trial (www.anzctr.org.au ACTRN12620000682943) of adults with neuromuscular disease referred for NIV implementation. Participants were stratified by disease (MND or Other diagnoses) and bulbar symptoms before randomization to NIV@Home or Usual care, with follow-up at 12-weeks. The primary outcome was NIV usage. Secondary outcomes included feasibility, health-related quality of life, symptoms, carer burden, and NIV experience (semi-structured qualitative interviews). Results: Twenty-three participants (MND bulbar = 9, MND non-bulbar = 11, Other = 3) were randomized (NIV@Home = 9). No statistical differences were observed in the percentage of MND participants using NIV for >4 hours/day (NIV@Home = 33% vs. Usual care = 60%, p = 0.370), average use (NIV@Home = 2.4 [1.5-9.3] vs. 5.3 [1.8-7.0] hours/day, p = 0.568), or secondary outcomes. In-home NIV implementation was feasible and safe but took more therapist time (NIV@Home = 278 [270-305] vs. 172 [130-200] minutes, p < 0.001). Participants in the NIV@Home group reported substantial advantages to receiving care in home. Conclusion: In-home NIV implementation is feasible and acceptable to people with MND but requires more therapist time. Larger studies are required to determine whether there are clinically important differences between this model of NIV initiation and a traditional hospital-based model.

Inpatient and long-term outcomes of individuals admitted for weaning from mechanical ventilation at a specialized ventilation weaning unit.

BACKGROUND: Weaning from invasive mechanical ventilation (IMV) in specialized weaning units has been demonstrated to be safe and cost-effective. Success rates and outcomes vary widely, probably relating to patient factors and unit expertise. METHODS: An audit was undertaken of patients admitted for weaning from IMV at the Austin Hospital Ventilation Weaning Unit (VWU) between March 2002 and January 2008. Weaning success, complications and both in-hospital and long-term mortality were examined and regression analysis was undertaken to examine factors related to these outcomes. RESULTS: Seventy-eight patients were admitted to the VWU after a median of 27 days of IMV at their referring centre. Weaning success rate (ventilator free or nocturnal non-invasive ventilation only) was 78.2% (n = 61). Inpatient mortality was 10.2% (n = 8) and serious complications were infrequent. Progressive neuromuscular disease (odds ratio 0.10) and sepsis during admission to the VWU (odds ratio 0.09) were predictive of weaning failure at discharge. Overall survival at 12 months following discharge from the VWU was 66.7% (n = 52) with most survivors residing in the community. Increasing age (hazard ratio 1.93), referral from rural or outer metropolitan centres (hazard ratio 3.57 and 2.37 respectively) and a diagnosis of chronic obstructive pulmonary disease were associated with increased long-term mortality. CONCLUSION: High rates of weaning success with infrequent complications and low mortality were achieved in this specialized non-intensive care unit-based weaning unit. The VWU may provide a useful template for the development of similar units elsewhere.

A narrative review on pain control interventions for non-surgical pleural procedures.

Pleural diseases are common and frequently result in disabling symptoms, impaired health-related quality of life and hospitalisation. Both diagnosis and management often require pleural procedures and despite a variety of pain control strategies available for clinicians to employ, many procedures are still complicated by pain and discomfort. This can interfere with procedure success and can limit patient satisfaction. This review examines the evidence for pain control strategies for people undergoing non-surgical pleural procedures. A systematic literature search was undertaken to identify published studies examining different pain control strategies including pharmacological (sedatives, paravertebral blocks, erector spinae blocks, intrapleural anaesthesia, epidural anaesthesia, local anaesthetic, methoxyflurane, non-steroidal anti-inflammatory drugs [NSAIDs], opioids) and non-pharmacological measures (transcutaneous electric nerve stimulation [TENS], cold application and changes to the intervention or technique). Current literature is limited by heterogeneous study design, small participant numbers and use of different endpoints. Strategies that were more effective than placebo or standard care at improving pain included intrapleural local anaesthesia, paravertebral blocks, NSAIDs, small-bore intercostal catheters (ICC), cold application and TENS. Inhaled methoxyflurane, thoracic epidural anaesthesia and erector spinae blocks may also be useful approaches but require further evaluation to determine their roles in routine non-surgical pleural procedures. Future research should utilise reliable and repeatable study designs and reach consensus in endpoints to allow comparability between findings and thus provide the evidence-base to achieve standardisation of pain management approaches.

Effect of Intensity of Home Noninvasive Ventilation in Individuals With Neuromuscular and Chest Wall Disorders: A Systematic Review and Meta-Analysis of Individual Participant Data.

INTRODUCTION: Home noninvasive ventilation (NIV), targeting a reduction of carbon dioxide with a combination of sufficient inspiratory support and backup-rate improves outcomes in patients with chronic obstructive pulmonary disease. The aim of this systematic review with individual participant data (IPD) meta-analysis was to evaluate the effects of intensity of home NIV on respiratory outcomes in individuals with slowly progressive neuromuscular (NMD) or chest-wall disorders (CWD). METHODS: Controlled, non-controlled and cohort studies indexed between January-2000 and December-2020 were sought from Medline, Embase and the Cochrane Central Register. Outcomes were diurnal PaCO2, PaO2, daily NIV usage, and interface type (PROSPERO-CRD 42021245121). NIV intensity was defined according to the Z-score of the product of pressure support (or tidal volume) and backup-rate. RESULTS: 16 eligible studies were identified; we obtained IPD for 7 studies (176 participants: 113-NMD; 63-CWD). The reduction in PaCO2 was greater with higher baseline PaCO2. NIV intensity per se was not associated with improved PaCO2 except in individuals with CWD and the most severe baseline hypercapnia. Similar results were found for PaO2. Daily NIV usage was associated with improvement in gas exchange but not with NIV intensity. No association between NIV intensity and interface type was found. CONCLUSION: Following home NIV initiation in NMD or CWD patients, no relationship was observed between NIV intensity and PaCO2, except in individuals with the most severe CWD. The amount of daily NIV usage, rather than intensity, is key to improving hypoventilation in this population during the first few months after introduction of therapy.

Interstitial lung disease in a patient treated with oxaliplatin, 5-fluorouracil and leucovorin (FOLFOX) for metastatic colorectal cancer.

BACKGROUND: Oxaliplatin in combination with 5-fluorouracil (5-FU) and leucovorin (FOLFOX) is a common chemotherapeutic regimen for advanced colorectal cancer. Here, we present a case of interstitial lung disease associated with FOLFOX therapy. CASE REPORT: A 74-year-old man with a history of metastatic colorectal cancer was admitted with a four week history of progressive dyspnoea and evidence of severe respiratory failure. He had recently completed six cycles of FOLFOX chemotherapy in the months prior to presentation. Investigations did not reveal convincing evidence of infection or pulmonary embolism. CT chest demonstrated widespread pulmonary infiltrates and interlobular septal thickening. The patient was commenced on both broad spectrum antibiotic therapy and high dose corticosteroid treatment however his respiratory failure continued to progress. The patient died four days after admission due to progressive respiratory failure. Subsequent post-mortem examination demonstrated evidence of diffuse alveolar damage without evidence of tumour infiltration, infection or pulmonary embolism. CONCLUSIONS: Although infrequent, pulmonary toxicity can occur in association with FOLFOX therapy. Cessation of therapy and prompt initiation of corticosteroids may improve outcomes.

Improving access to ward-based respiratory failure management: a case study in the development of a respiratory care unit at an Australian metropolitan health service.

This case study describes the implementation of a ward-based respiratory care unit to improve access to specialised respiratory failure management at an Australian metropolitan health service. Using a case study approach, we describe the conception, development and implementation of a respiratory care unit within a previously inexperienced ward. Key barriers and facilitators are explored and the importance of a safety culture and an aspiration for continuous quality improvement are detailed. Three key aspects of implementation were identified: physical environment, expertise and governance. Continuous review of clinical and quality data was also considered critical to success. Stakeholder engagement was identified as both a barrier and facilitator to successful implementation. Early success was demonstrated through increased utilisation of respiratory interventions but with less utilisation of the intensive care unit and no apparent deterioration in clinical outcomes. Successful implementation of ward-based management of respiratory failure can be undertaken within non-tertiary settings but requires a comprehensive plan. Essential aspects include the support of clinical champions, early and continuous stakeholder engagement and an aspirational culture of safety and continuous quality improvement.What is known about the topic?Non-invasive ventilation and high-flow oxygen therapy are now established as key treatments in the management of acute respiratory failure. Access to these treatments is often limited to critical care locations (emergency department, intensive care unit (ICU) and operating theatre), but ward-based use can be safe and effective when applied with appropriate clinical policies, expertise and staffing.What does this paper add?This report describes the successful and rapid development of a specialised respiratory care unit within an inexperienced ward at an Australian metropolitan health service. Prior to development of the unit, the health service only provided non-invasive ventilation and high-flow oxygen therapy within critical care locations. Successful implementation was associated with increased utilisation of these therapies with significantly less ICU utilisation and no apparent deterioration in outcomes.What are the implications for practitioners?An explanation of a model for implementation is provided that may help health services improve access to complex respiratory failure management outside of critical care locations. Key factors in the success of the model are identified and examined.

Typical within and between person variability in non-invasive ventilator derived variables among clinically stable, long-term users.

BACKGROUND: Despite increasing capacity to remotely monitor non-invasive ventilation (NIV), how remote data varies from day to day and person to person is poorly described. METHODS: Single-centre, 2-month, prospective study of clinically stable adults on long-term NIV which aimed to document NIV-device variability. Participants were switched to a ventilator with tele-monitoring capabilities. Ventilation settings and masking were not altered. Raw, extensible markup language data files were provided directly from Philips Respironics (EncoreAnywhere). A nested analysis of variance was conducted on each ventilator variable to apportion the relative variation between and within participants. RESULTS: Twenty-nine people were recruited (four withdrew, one had insufficient data for analyses; 1364 days of data). Mean age was 54.0 years (SD 18.4), 58.3% male with body mass index of 37.0 kg/m2 (13.7). Mean adherence was 8.53 (2.23) hours/day and all participants had adherence >4 hours/day. Variance in ventilator-derived indices was predominantly driven by differences between participants; usage (61% between vs 39% within), Apnoea-Hypopnoea Index (71% vs 29%), unintentional (64% vs 36%) and total leak (83% vs 17%), tidal volume (93% vs 7%), minute ventilation (92% vs 8%), respiratory rate (92% vs 8%) and percentage of triggered breaths (93% vs 7%). INTERPRETATION: In this clinically stable cohort, all device-derived indices were more varied between users than the day-to-day variation within individuals. We speculate that normative ranges and thresholds for clinical intervention need to be individualised, and further research is necessary to determine the clinically important relationships between clinician targets for therapy and patient-reported outcomes.

Measuring Adherence to Long-Term Noninvasive Ventilation.

BACKGROUND: Obtaining benefits from long-term noninvasive ventilation (NIV) relies on achieving adequate adherence to treatment. Reported adherence to NIV is variable and could be influenced by high-volume users and attrition of nonusers and those who die. This observational study aimed to describe patterns of use and adherence rates in new unselected users of NIV. METHODS: All adults (> 18 y old) commencing long-term NIV were consecutively enrolled and followed for 6 months. Ventilator data were manually downloaded from devices and usage (minutes per day) was collected. Subjects were categorized into adherent users (≥ 4 h/d) and nonadherent users (< 4 h/d). RESULTS: Data were obtained from 86 subjects. Most (65%) had motor neuron disease, and most commenced NIV in an out-patient setting (72%). At one month after NIV implementation, overall average daily use was 302.1 min/d and categorical adherence was 57%. At 6 months or prior to death, overall average daily use increased (388.7 min/d), but categorical adherence was similar (62%). The majority of subjects (84%) remained in the same adherence category from their first month to their sixth month of use or death. Individuals with motor neuron disease demonstrated significantly lower rates of adherence compared to the rest of the cohort at 1 month (48% vs 73%, P = .03). In those who died within the study period (n = 19, all with motor neuron disease), this difference persisted to death (42% at death vs 73% at 6 months, P = .032). CONCLUSIONS: Average daily usage may conceal true prevalence of adherence or nonadherence to NIV within a population. Reporting both average daily use data and categorical adherence rates (using a threshold of 4 h/d) may improve transparency of reported outcomes from clinical trials and identifies a therapeutic target for home mechanical ventilation services for quality improvement.

Autocycling During Noninvasive Positive Pressure Ventilation Producing a Prolonged Severe Apnea and Syncope, Further Insights.

CITATION: Mu S, Howard ME, Hannan L. Autocycling during noninvasive positive pressure ventilation producing a prolonged severe apnea and syncope, further insights. J Clin Sleep Med. 2019;15(9):1379.

Autocycling During Noninvasive Positive Pressure Ventilation Producing a Prolonged Severe Apnea and Syncope.

ABSTRACT: Autocycling is a form of patient-ventilator asynchrony that can occur during mechanical ventilation. In the case described, autocycling during noninvasive ventilation led to severe hyperventilation and subsequently produced a prolonged central apnea that resulted in syncope. This case represents the first description of a severe adverse event from autocycling during noninvasive ventilation.

Effect of Intensity of Home Noninvasive Ventilation in Individuals With Neuromuscular and Chest Wall Disorders: A Systematic Review and Meta-Analysis of Individual Participant Data

Introduction: Home noninvasive ventilation (NIV), targeting a reduction of carbon dioxide with a combination of sufficient inspiratory support and backup-rate improves outcomes in patients with chronic obstructive pulmonary disease. The aim of this systematic review with individual participant data (IPD) meta-analysis was to evaluate the effects of intensity of home NIV on respiratory outcomes in individuals with slowly progressive neuromuscular (NMD) or chest-wall disorders (CWD). Methods: Controlled, non-controlled and cohort studies indexed between January-2000 and December-2020 were sought from Medline, Embase and the Cochrane Central Register. Outcomes were diurnal PaCO2, PaO2, daily NIV usage, and interface type (PROSPERO-CRD 42021245121). NIV intensity was defined according to the Z-score of the product of pressure support (or tidal volume) and backup-rate. Results: 16 eligible studies were identified; we obtained IPD for 7 studies (176 participants: 113-NMD; 63-CWD). The reduction in PaCO2 was greater with higher baseline PaCO2. NIV intensity per se was not associated with improved PaCO2 except in individuals with CWD and the most severe baseline hypercapnia. Similar results were found for PaO2. Daily NIV usage was associated with improvement in gas exchange but not with NIV intensity. No association between NIV intensity and interface type was found. Conclusion: Following home NIV initiation in NMD or CWD patients, no relationship was observed between NIV intensity and PaCO2, except in individuals with the most severe CWD. The amount of daily NIV usage, rather than intensity, is key to improving hypoventilation in this population during the first few months after introduction of therapy. (AU)