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OBJECTIVE: CTD-associated interstitial lung disease (ILD) often fails to respond to conventional immunomodulatory agents. There is now considerable interest in the use of rituximab in systemic autoimmune CTD in patients refractory to standard treatments. The aim of this study was to review the experience of North Bristol NHS Trust managing patients with CTD-associated ILD with rituximab and explore possible associations with treatment response. METHODS: We conducted a retrospective analysis of all patients who received rituximab under the Bristol CTD-ILD service, having failed to respond to other immunomodulatory treatments. Results were collated for pulmonary function and radiological outcomes before and after treatment. RESULTS: Twenty-four patients were treated with rituximab. Their physiological parameters had failed to improve despite other immunomodulatory agents, with a mean change in forced vital capacity (FVC) prior to therapy of - 3.3% (95% CI - 5.6, -1.1) and mean change in diffusing capacity of carbon monoxide of - 4.3% (95% CI - 7.7, -0.9). After rituximab, radiology remained stable or improved for 11 patients, while worsening was observed in 9 patients. The decline in FVC was halted following treatment, with a mean change of + 4.1% (95% CI 0.9, 7.2), while diffusing capacity of carbon monoxide was stable [mean change +2.1% (95% CI - 1.0, 5.2)]. Patients with myositis overlap or antisynthetase syndrome appeared to respond well to treatment, with four patients showing clinically significant improvement in FVC >10%. CONCLUSION: Rituximab is a therapeutic option in treatment-refractory CTD-associated ILD. Some disease subgroups may respond better than others, however, more work is needed to define its role in managing these patients.
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Enfermedades Autoinmunes/complicaciones , Enfermedades del Tejido Conjuntivo/complicaciones , Factores Inmunológicos/uso terapéutico , Enfermedades Pulmonares Intersticiales/tratamiento farmacológico , Rituximab/uso terapéutico , Adulto , Anciano , Enfermedades Autoinmunes/tratamiento farmacológico , Enfermedades Autoinmunes/fisiopatología , Enfermedades del Tejido Conjuntivo/tratamiento farmacológico , Enfermedades del Tejido Conjuntivo/fisiopatología , Femenino , Humanos , Pulmón/diagnóstico por imagen , Pulmón/fisiopatología , Enfermedades Pulmonares Intersticiales/diagnóstico por imagen , Enfermedades Pulmonares Intersticiales/etiología , Masculino , Persona de Mediana Edad , Radiología/métodos , Radiología/estadística & datos numéricos , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: A large subgroup of people with interstitial lung disease (ILD) are normoxic at rest, but rapidly desaturate on exertion. This can limit exercise capacity and worsen dyspnoea. The use of ambulatory or short-burst oxygen when mobilising or during other activities, may improve exercise capacity and relieve dyspnoea. OBJECTIVES: To determine the effects of ambulatory and short-burst oxygen therapy, separately, on exercise capacity, dyspnoea and quality of life in people who have interstitial lung disease (ILD), particularly those with idiopathic pulmonary fibrosis (IPF). SEARCH METHODS: We conducted searches in the Cochrane Airways Group Specialised Register (all years to May 2016), Cochrane Central Register of Controlled Trials (CENTRAL) (all years to May 2016), MEDLINE (Ovid) (1950 to 4th May 2016) and EMBASE (Ovid) (1974 to 4th May 2016). We also searched the reference lists of relevant studies, international clinical trial registries and respiratory conference abstracts for studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) or quasi-RCTs that compared ambulatory or short-burst oxygen with a control group in people with ILD of any origin. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies for inclusion and assessed risk of bias in the included studies. We extracted data from included studies using a prepared checklist, including study characteristics and results. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria to assess the quality of the included studies. MAIN RESULTS: Three studies (including 98 participants, all of whom had IPF) met the inclusion criteria of this review. These studies were conducted in hospital respiratory physiology laboratories. Two studies did not demonstrate any beneficial effect of supplemental oxygen on exercise capacity or exertional dyspnoea. Neither of these studies titrated oxygen requirements to prevent ongoing exertional desaturation. One study showed an increase in exercise capacity as assessed by endurance time with supplemental oxygen. We did not identify any studies that examined the effect of ambulatory oxygen on health-related quality of life, survival, costs or time to exacerbation or hospitalisation. No study reported any adverse events. The quality of evidence for all three studies, as assessed by GRADE criteria, was low. AUTHORS' CONCLUSIONS: This review found no evidence to support or refute the use of ambulatory or short burst oxygen in ILD due to the limited number of included studies and data. Further research is needed to examine the role of this treatment.
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Fibrosis Pulmonar Idiopática/terapia , Enfermedades Pulmonares Intersticiales/terapia , Terapia por Inhalación de Oxígeno/métodos , Atención Ambulatoria/métodos , Disnea/terapia , Tolerancia al Ejercicio , Humanos , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
Interstitial lung disease (ILD) is a growing field of respiratory medicine in which novel therapies are emerging. It is important that trainees gain competence and confidence in this area. To explore the training experiences of specialty trainees, we conducted a survey of their practical experience and confidence in diagnosing and managing ILD.
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Internado y Residencia , Enfermedades Pulmonares Intersticiales/diagnóstico , Enfermedades Pulmonares Intersticiales/terapia , Neumología/educación , Actitud del Personal de Salud , Recolección de Datos , Inglaterra , Humanos , Autoeficacia , Sociedades MédicasRESUMEN
The clinical syndrome of acute lung injury (ALI) occurs as a result of an initial acute systemic inflammatory response. This can be consequent to a plethora of insults, either direct to the lung or indirect. The insult results in increased epithelial permeability, leading to alveolar flooding with a protein-rich oedema fluid. The resulting loss of gas exchange leads to acute respiratory failure and typically catastrophic illness, termed acute respiratory distress syndrome (ARDS), requiring ventilatory and critical care support. There remains a significant disease burden, with some estimates showing 200,000 cases each year in the USA with a mortality approaching 50%. In addition, there is a significant burden of morbidity in survivors. There are currently no disease-modifying therapies available, and the most effective advances in caring for these patients have been in changes to ventilator strategy as a result of the ARDS network studies nearly 15 years ago. Here, we will give an overview of more recent advances in the understanding of the cellular biology of ALI and highlight areas that may prove fertile for future disease-modifying therapies.
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Endotelio Vascular/fisiopatología , Alveolos Pulmonares/fisiopatología , Síndrome de Dificultad Respiratoria/metabolismo , Síndrome de Dificultad Respiratoria/fisiopatología , Mucosa Respiratoria/fisiopatología , Adulto , Permeabilidad Capilar , Citocinas/metabolismo , Matriz Extracelular/metabolismo , Humanos , Metaloproteinasas de la Matriz/metabolismo , Neutrófilos/metabolismo , Receptor para Productos Finales de Glicación Avanzada/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
INTRODUCTION: Sarcoidosis is a multi-system granulomatous disease most commonly involving the lungs. It may be incidentally diagnosed during imaging studies for other conditions or non-specific symptoms. The appropriate follow-up of incidentally diagnosed asymptomatic stage 1 disease has not been well defined. OBJECTIVE: To define the clinical course of incidentally diagnosed asymptomatic stage 1 sarcoidosis and propose an algorithm for the follow-up of these patients. METHODOLOGY: A retrospective case note analysis was performed of all EBUS-TBNA (endobronchial ultrasound-guided transbronchial needle aspiration)-confirmed cases of stage 1 sarcoidosis presenting incidentally to Bristol and Liverpool Interstitial Lung Disease services. Clinical history, serology results, imaging scans, and lung function parameters were examined at baseline, 12, and 24 months. A cost analysis was performed comparing the cost of the current 2-year follow-up guidance to a 1 year follow-up period. RESULTS: Sixty-seven patients were identified as the final cohort. There was no significant change in the pulmonary function tests over the two-year follow-up period. Radiological disease stability was observed in the majority of patients (58%, n = 29), and disease regression was evidenced in 40% (n = 20) at 1 year. Where imaging was performed at 2 years, the majority (69.8%, n = 37) had radiological evidence of disease regression, and 30.2% (n = 16) showed radiological evidence of stability. All patients remained asymptomatic and did not require therapeutic intervention over the study period. CONCLUSIONS: Our results show that asymptomatic patients with incidental findings of thoracic lymph nodal non-caseating granulomas do not progress over a 2-year period. Our results suggest that the prolonged secondary-care follow-up of such patients may not be necessary. We propose that these patients are followed up for 1 year with a further year of patient-initiated follow-up (PIFU) prior to discharge.
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Granulomatosis with polyangiitis (GPA, formerly Wegener's granulomatosis) can present diagnostic difficulties for the clinician as there can be considerable overlap in features with tuberculosis (TB). Indeed, there are documented cases both of coexisting TB and GPA, and cases wrongly diagnosed as GPA when in fact TB was the underlying diagnosis. This lesson presents a case of GPA where TB was also considered as a differential and highlights the diagnostic and management difficulties when this is the case.
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Granulomatosis con Poliangitis/diagnóstico , Poliangitis Microscópica/diagnóstico , Tuberculosis/diagnóstico , Biopsia , Diagnóstico Diferencial , Granulomatosis con Poliangitis/complicaciones , Humanos , Masculino , Poliangitis Microscópica/complicaciones , Mucosa Nasal/patología , Tomografía Computarizada por Rayos X , Adulto JovenRESUMEN
Cross-reactivity of murine and recently human CD8(+) T cells between different viral peptides, i.e., heterologous immunity, has been well characterized. However, the directionality and quality of these cross-reactions is critical in determining their biological importance. Herein we analyzed the response of human CD8(+) T cells that recognize both a hepatitis C virus peptide (HCV-NS3) and a peptide derived from the influenza neuraminidase protein (Flu-NA). To detect the cross-reactive CD8(+) T cells, we used peptide-MHC class I complexes (pMHCs) containing a new mutant form of MHC class I able to bind CD8 more strongly than normal MHC class I complexes. T cell responses against HCV-NS3 and Flu-NA peptide were undetectable in normal donors. In contrast, some responses against the Flu-NA peptide were identified in HCV(+) donors who showed strong HCV-NS3-specific reactivity. The Flu-NA peptide was a weak agonist for CD8(+) T cells in HCV(+) individuals on the basis of novel pMHCs and functional assays. These data support the idea of cross-reactivity between the 2 peptides, but indicate that reactivity toward the Flu-NA peptide is highly CD8-dependent and occurs predominantly after priming during HCV infection. Our findings indicate the utility of the novel pMHCs in dissecting cross-reactivity and suggest that cross-reactivity between HCV and influenza is relatively weak. Further studies are needed to relate affinity and functionality of cross-reactive T cells.
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Linfocitos T CD8-positivos/inmunología , Hepatitis C/inmunología , Orthomyxoviridae/inmunología , Reacciones Cruzadas , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Neuraminidasa/inmunología , Proteínas de la Matriz Viral/inmunología , Proteínas no Estructurales Virales/inmunologíaRESUMEN
BACKGROUND: Long-term nitrofurantoin (NF) treatment can result in pulmonary and hepatic injury. Current guidelines do not outline the type or frequency of monitoring required for detection of these injuries. AIM: To assess 1) awareness of NF complications among prescribers; 2) monitoring practice; and 3) to describe the pulmonary sequelae of NF-related complications. DESIGN & SETTING: Evaluation of prescribing habits by questionnaires and review of GP databases, and case-note review in secondary care. METHOD: The following study procedures were undertaken: 1) an electronic questionnaire was distributed to prescribers, interrogating prescribing and monitoring practices, and awareness of complications; 2) an analysis was undertaken (June-July 2020) of NF monitoring among GPs in the local clinical commissioning group (CCG); and 3) a case review was carried out of patients diagnosed with NF-induced interstitial lung disease (NFILD) at the interstitial lung disease (ILD) centre (2014-2020). RESULTS: A total of 125 prescribers of long-term NF responded to the questionnaire (82.4% GPs; 12.0% urologists). Many were unaware of the potential for liver (42.4%) and lung (28.0%) complications; 40.8% and 52.8% never monitored for these, respectively. Only 53.3% of urologists believed themselves responsible for arranging monitoring, while nearly all GPs believed this to be the prescriber's responsibility (94.2%). One-third of all responders considered current British National Formulary (BNF) guidelines 'not at all sufficient/clear', with mean clarity scoring of 2.2/5. Among patients with NFILD (n = 46), NF had been prescribed most often (69.6%) for treatment of recurrent UTI and 58.6% (n = 27) were prescribed for >6 months. On withdrawal of the medication 61.4% displayed resolution (completely or minimal fibrosis), while 15.9% of patients had progressive lung fibrosis. CONCLUSION: NF can cause marked or irreversible lung complications and there is currently a shortfall in awareness and monitoring. Existing monitoring guidelines should be augmented.
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The heterogeneity of interstitial lung disease (ILD) results in prognostic uncertainty concerning end-of-life discussions and optimal timing for transplantation. Effective prognostic markers and prediction models are needed. Cardiopulmonary exercise testing (CPET) provides a comprehensive assessment of the physiological changes in the respiratory, cardiovascular and musculoskeletal systems in a controlled laboratory environment. It has shown promise as a prognostic factor for other chronic respiratory conditions. We sought to evaluate the prognostic value of CPET in predicting outcomes in longitudinal studies of ILD. MEDLINE, Embase and the Cochrane Database of Systematic Reviews were used to identify studies reporting the prognostic value of CPET in predicting outcomes in longitudinal studies of ILD. Study quality was assessed using the Quality in Prognosis Study risk of bias tool. Thirteen studies were included that reported the prognostic value of CPET in ILD. All studies reported at least one CPET parameter predicting clinical outcomes in ILD, with survival being the principal outcome assessed. Maximum oxygen consumption, reduced ventilatory efficiency and exercise-induced hypoxaemia were all reported to have prognostic value in ILD. Issues with study design (primarily due to inherent problems of retrospective studies, patient selection and presentation of numerous CPET parameters), insufficient adjustment for important confounders and inadequate statistical analyses limit the strength of the conclusions that can be drawn at this stage. There is insufficient evidence to confirm the value of CPET in facilitating "real-world" clinical decisions in ILD. Additional prospective studies are required to validate the putative prognostic associations reported in previous studies in carefully phenotyped patient populations.
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Antirreumáticos/efectos adversos , Granuloma/inducido químicamente , Enfermedades Pulmonares Intersticiales/tratamiento farmacológico , Fracturas de la Columna Vertebral/inducido químicamente , Biopsia , Diagnóstico por Imagen , Progresión de la Enfermedad , Etanercept , Femenino , Granuloma/diagnóstico , Granuloma/cirugía , Humanos , Inmunoglobulina G/efectos adversos , Enfermedades Pulmonares Intersticiales/fisiopatología , Enfermedades Pulmonares Intersticiales/cirugía , Persona de Mediana Edad , Receptores del Factor de Necrosis Tumoral , Pruebas de Función Respiratoria , Fracturas de la Columna Vertebral/diagnóstico , Fracturas de la Columna Vertebral/cirugía , Cirugía Torácica Asistida por VideoAsunto(s)
Neoplasias Pulmonares/diagnóstico , Linfangiomioma/diagnóstico , Derrame Pleural Maligno/diagnóstico , Radiografía Torácica/métodos , Tomografía Computarizada por Rayos X , Biopsia , Diagnóstico Diferencial , Femenino , Humanos , Pulmón/diagnóstico por imagen , Pulmón/patología , Pulmón/cirugía , Neoplasias Pulmonares/complicaciones , Neoplasias Pulmonares/cirugía , Linfangiomioma/complicaciones , Linfangiomioma/cirugía , Persona de Mediana Edad , Derrame Pleural , Derrame Pleural Maligno/etiología , NeumonectomíaRESUMEN
OBJECTIVE: We propose a novel depth-based photoplethysmography (dPPG) approach to reduce motion artifacts in respiratory volume-time data and improve the accuracy of remote pulmonary function testing (PFT) measures. METHOD: Following spatial and temporal calibration of two opposing RGB-D sensors, a dynamic three-dimensional model of the subject performing PFT is reconstructed and used to decouple trunk movements from respiratory motions. Depth-based volume-time data is then retrieved, calibrated, and used to compute 11 clinical PFT measures for forced vital capacity and slow vital capacity spirometry tests. RESULTS: A dataset of 35 subjects (298 sequences) was collected and used to evaluate the proposed dPPG method by comparing depth-based PFT measures to the measures provided by a spirometer. Other comparative experiments between the dPPG and the single Kinect approach, such as Bland-Altman analysis, similarity measures performance, intra-subject error analysis, and statistical analysis of tidal volume and main effort scaling factors, all show the superior accuracy of the dPPG approach. CONCLUSION: We introduce a depth-based whole body photoplethysmography approach, which reduces motion artifacts in depth-based volume-time data and highly improves the accuracy of depth-based computed measures. SIGNIFICANCE: The proposed dPPG method remarkably drops the error mean and standard deviation of FEF , FEF , FEF, IC , and ERV measures by half, compared to the single Kinect approach. These significant improvements establish the potential for unconstrained remote respiratory monitoring and diagnosis.
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Fotopletismografía/métodos , Tecnología de Sensores Remotos/métodos , Pruebas de Función Respiratoria/métodos , Procesamiento de Señales Asistido por Computador , Imagen de Cuerpo Entero/métodos , Adulto , Artefactos , Femenino , Humanos , Imagenología Tridimensional/métodos , Masculino , Movimiento (Física)RESUMEN
OBJECTIVES: Palliative care is underused in non-malignant respiratory diseases, including interstitial lung diseases (ILDs). We investigated current practices around palliative and supportive care and explored the impact of a supportive care decision aid tool. METHODS: This was a single centre study in a UK ILD centre. Retrospective analysis of hospice referrals and patients with idiopathic pulmonary fibrosis (IPF) under the Bristol ILD (BILD) service were used to identify unmet palliative and supportive care needs. Using quality improvement methodology, we explored the impact of a supportive care decision aid on clinician behaviours for patients with ILD. RESULTS: 108 patients with ILD were referred for hospice care between 2010 and 2015, representing 0.15% of all referrals, compared with a population prevalence of IPF of 0.9%. The median interval between referral and death was 124 days.Records were reviewed for 64 deceased and 89 living patients with IPF seen on July-December 2014. The decision aid was prospectively assessed with 73 patients. The deceased patients had greater markers of severity. There were no other differences between the groups.After introduction, the decision aid tool was completed for 49.3% of patients and resulted in significant increases in documented discussion of referral to palliative care (11.2%vs53.6%, p<0.01) and end-of-life discussions (15.7%vs91.8%, p<0.01). Tool completion led to an increase in referral for palliative care (2.7%vs16.7%, p<0.01). CONCLUSION: Palliative care services are underused in ILD and a supportive care decision aid can prompt consideration of palliative and supportive care needs.
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Fibrosis Pulmonar Idiopática/terapia , Enfermedades Pulmonares Intersticiales/terapia , Cuidados Paliativos/estadística & datos numéricos , Pautas de la Práctica en Medicina/estadística & datos numéricos , Derivación y Consulta , Anciano , Toma de Decisiones Clínicas , Técnicas de Apoyo para la Decisión , Femenino , Humanos , Fibrosis Pulmonar Idiopática/epidemiología , Enfermedades Pulmonares Intersticiales/epidemiología , Masculino , Persona de Mediana Edad , Evaluación de Necesidades , Prevalencia , Estudios Retrospectivos , Reino Unido/epidemiologíaRESUMEN
Purpose: Pirfenidone and nintedanib are two novel antifibrotic agents licensed for the treatment IPF. Prior to being approved for use in England for patients with FVC >50% and <80%, these were made available for all IPF patients under the Mild Patient Program (MPP) and Patient In Need Scheme (PIN). Prescribing of these medications is restricted to specialist centers. We sought to characterize the population of patients prescribed antifibrotics and determine the drug tolerability of these medications in the Northern hub of the Southwest of England regional ILD network. Methods: A retrospective analysis of all patients treated with antifibrotics between August 2012 and July 2017 was undertaken. Baseline characteristics including patient demographics and pulmonary physiology, in addition to drug tolerability and reasons for treatment cessation were collated. Data were compared using unpaired student's t-test, Chi-squared, Mann-Whitney rank sum or ANOVA as appropriate. Logistic regression analysis evaluated clinical characteristics associated with discontinuation of pirfenidone therapy. P < 0.05 was considered statistically significant. Findings: A total of 164 patients, all with consensus diagnoses of IPF, were identified. Of these, 70.1% (115/164) received pirfenidone as their initial therapy. Baseline age, gender and pulmonary physiology did not differ significantly between groups. Drug discontinuation occurred most commonly due to adverse drug reactions events (ADRs) for both pirfenidone [40.0% (46/115)] and nintedanib [16.3% (8/49)]. Anorexia, rash and gastrointestinal disturbance were reported most commonly as the reason for cessation of pirfenidone; anorexia, nausea and weight loss for nintedanib. Duration of therapy prior to discontinuation because of ADRs did not differ significantly between medication groups but patients with a baseline FVC < 65% predicted, had a significantly shorter duration of pirfenidone prior to discontinuation due to ADRs, compared to those with a FVC 65-80% predicted. Multivariate logistic regression did not identify any independent baseline characteristics that predicted discontinuation of pirfenidone therapy prior to 52 weeks. Implications: Idiopathic pulmonary fibrosis (IPF) patients treated with nintedanib had comparable treatment emergent adverse event (TEAE) profiles in clinical practice to those reported in clinical trials. The TEAE profile of pirfenidone was higher than clinical trial data would suggest, although comparable to real-world datasets. Further work is required to explore the possible reasons underpinning this finding, including whether this is related to population co-morbidities or center threshold. No new safety concerns were identified.
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INTRODUCTION: Patients with progressive idiopathic fibrotic interstitial lung disease (ILD), such as those with idiopathic pulmonary fibrosis (IPF), can have an aggressive disease course, with a median survival of only 3-5 years from diagnosis. The palliative care needs of these patients are often unmet. There are calls for new models of care, whereby the patient's usual respiratory clinician remains central to the integration of palliative care principles and practices into their patient's management, but the optimal model of service delivery has yet to be determined. METHODS: We developed a novel, collaborative, multidisciplinary team (MDT) meeting between our palliative care, psychology and ILD teams with the principal aim of integrating specialist care to ensure the needs of persons with ILD, and their caregivers were identified and met by referral to the appropriate service. The objective of this study was to assess the effectiveness of this novel MDT meeting on the assessment of a patient's palliative care needs. RESULTS: Significant increases in advance care planning discussions were observed, in conjunction with increased referrals to community courses and teams, following introduction of this novel MDT. CONCLUSIONS: Our results suggest that our collaborative MDT is an effective platform to address patients' unmet palliative care needs. Further work is required to explore the effect of our model on achieving the preferred place of death and reductions in unplanned hospital admissions.
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Idiopathic pulmonary fibrosis (IPF) has an unpredictable course and prognostic factors are incompletely understood. We aimed to identify prognostic factors, including multidimensional indices from a significant IPF cohort at the Bristol Interstitial Lung Disease Centre in the UK. Patients diagnosed with IPF between 2007 and 2014 were identified. Longitudinal pulmonary physiology and exercise testing results were collated, with all-cause mortality used as the primary outcome. Factors influencing overall, 12- and 24-month survival were identified using Cox proportional hazards modelling and receiver operating characteristic curve analysis. We found in this real-world cohort of 167 patients, diffusing capacity for carbon monoxide (DLCO) and initiation of long-term oxygen were independent markers of poor prognosis. Exercise testing results predicted 12-month mortality as well as DLCO, but did not perform as well for overall survival. The Composite Physiological Index was the best performing multidimensional index, but did not outperform DLCO. Our data confirmed that patients who experienced a fall in forced vital capacity (FVC) >10% had significantly worse survival after that point (p=0.024). Our data from longitudinal follow-up in IPF show that DLCO is the best individual prognostic marker, outperforming FVC. Exercise testing is important in predicting early poor outcome. Regular and complete review should be conducted to ensure appropriate care is delivered in a timely fashion.
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Introduction: There is increasing interest in technologies that may enable remote monitoring of respiratory disease. Traditional methods for assessing respiratory function such as spirometry can be expensive and require specialist training to perform and interpret. Remote, non-contact tracking of chest wall movement has been explored in the past using structured light, accelerometers and impedance pneumography, but these have often been costly and clinical utility remains to be defined. We present data from a 3-Dimensional time-of-flight camera (found in gaming consoles) used to estimate chest volume during routine spirometry maneuvres. Methods: Patients were recruited from a general respiratory physiology laboratory. Spirometry was performed according to international standards using an unmodified spirometer. A Microsoft Kinect V2 time-of-flight depth sensor was used to reconstruct 3-dimensional models of the subject's thorax to estimate volume-time and flow-time curves following the introduction of a scaling factor to transform measurements to volume estimates. The Bland-Altman method was used to assess agreement of model estimation with simultaneous recordings from the spirometer. Patient characteristics were used to assess predictors of error using regression analysis and to further explore the scaling factors. Results: The chest volume change estimated by the Kinect camera during spirometry tracked respiratory rate accurately and estimated forced vital capacity (FVC) and vital capacity to within ± <1%. Forced expiratory volume estimation did not demonstrate acceptable limits of agreement, with 61.9% of readings showing >150 ml difference. Linear regression including age, gender, height, weight, and pack years of smoking explained 37.0% of the variance in the scaling factor for volume estimation. This technique had a positive predictive value of 0.833 to detect obstructive spirometry. Conclusion: These data illustrate the potential of 3D time-of-flight cameras to remotely monitor respiratory rate. This is not a replacement for conventional spirometry and needs further refinement. Further algorithms are being developed to allow its independence from spirometry. Benefits include simplicity of set-up, no specialist training, and cost. This technique warrants further refinement and validation in larger cohorts.
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OBJECTIVE: We propose a remote, noninvasive approach to develop pulmonary function testing (PFT) using a depth sensor. METHOD: After generating a point cloud from scene depth values, we construct a three-dimensional model of the subject's chest. Then, by estimating the chest volume variation throughout a sequence, we generate volume-time and flow-time data for two prevalent spirometry tests: forced vital capacity (FVC) and slow vital capacity (SVC). Tidal volume and main effort sections of volume-time data are analyzed and calibrated separately to remove the effects of a subject's torso motion. After automatic extraction of keypoints from the volume-time and flow-time curves, seven FVC ( FVC, FEV1, PEF, FEF 25%, FEF 50%, FEF 75%, and FEF [Formula: see text]) and four SVC measures ( VC, IC, TV, and ERV) are computed and then validated against measures from a spirometer. A dataset of 85 patients (529 sequences in total), attending respiratory outpatient service for spirometry, was collected and used to evaluate the proposed method. RESULTS: High correlation for FVC and SVC measures on intra-test and intra-subject measures between the proposed method and the spirometer. CONCLUSION: Our proposed depth-based approach is able to remotely compute eleven clinical PFT measures, which gives highly accurate results when evaluated against a spirometer on a dataset comprising 85 patients. SIGNIFICANCE: Experimental results computed over an unprecedented number of clinical patients confirm that chest surface motion is linearly related to the changes in volume of lungs, which establishes the potential toward an accurate, low-cost, and remote alternative to traditional cumbersome methods, such as spirometry.