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Polymyositis and dermatomyositis are autoimmune idiopathic systemic inflammatory diseases, characterized by various degrees of muscle inflammation and typical cutaneous lesions-the latter found in dermatomyositis. The underlying pathogenesis is characterized by a high level of uncertainty, and recent studies suggest diseases may have different immunopathological mechanisms. In polymyositis, components of the cellular immune system are involved, whereas in dermatomyositis, the pathogenesis is mainly mediated by the humoral immune response. The interstitial lung disease occurs in one-third of polymyositis and dermatomyositis patients associated with worse outcomes, showing an estimated excess mortality rate of around 40%. Lung involvement may also appear, such as a complication of muscle weakness, mainly represented by aspiration pneumonia or respiratory insufficiency. The clinical picture is characterized, in most cases, by progressive dyspnea and non-productive cough. In some cases, hemoptysis and chest pain are found. Onset can be acute, sub-acute, or chronic. Pulmonary involvement could be assessed by High Resolution Computed Tomography (HRCT), which may identify early manifestations of diseases. Moreover, Computed Tomography (CT) appearances can be highly variable depending on the positivity of myositis-specific autoantibodies. The most common pathological patterns include fibrotic and cellular nonspecific interstitial pneumonia or organizing pneumonia; major findings observed on HRCT images are represented by consolidations, ground-glass opacities, and reticulations. Other findings include honeycombing, subpleural bands, and traction bronchiectasis. In patients having Anti-ARS Abs, HRCT features may develop with consolidations, ground glass opacities (GGOs), and reticular opacities in the peripheral portions; nonspecific interstitial pneumonia or nonspecific interstitial pneumonia mixed with organizing pneumonia have been reported as the most frequently encountered patterns. In patients with anti-MDA5 Abs, mixed or unclassifiable patterns are frequently observed at imaging. HRCT is a sensitive method that allows one not only to identify disease, but also to monitor the effectiveness of treatment and detect disease progression and/or complications; however, radiological findings are not specific. Therefore, aim of this pictorial essay is to describe clinical and radiological features of interstitial lung diseases associated with polymyositis and dermatomyositis, emphasizing the concept that gold standard for diagnosis and classification-should be based on a multidisciplinary approach.
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Doenças Autoimunes , Dermatomiosite , Doenças Pulmonares Intersticiais , Polimiosite , Humanos , Dermatomiosite/complicações , Dermatomiosite/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Pulmão/patologia , Polimiosite/complicações , Polimiosite/diagnóstico por imagem , Polimiosite/patologia , Doenças Pulmonares Intersticiais/complicações , Doenças Pulmonares Intersticiais/diagnóstico por imagem , Radiografia , Doenças Autoimunes/complicações , Estudos RetrospectivosRESUMO
Increased oxidative stress may contribute to cancer anorexia, which could be ameliorated by antioxidant supplementation. methylcholanthrene (MCA) sarcoma-bearing Fisher rats were studied. After tumour inoculation, rats were randomly assigned to standard diet (CTR group, n = 6), or to an antioxidant-enriched diet (AOX group, n = 8). Eight more rats (STD-AOX group) switched from standard to antioxidant diet when anorexia developed. At the end of the study, food intake (FI, g/d), body weight and tumour weight (g) were recorded, and plasma samples were obtained. On day 16, anorexia has appeared only in CTR and STD-AOX animals. At the end of the study, FI in AOX animals was still higher than in the other groups (p = 0.08). No differences in body and tumour weights were observed among groups. However, hydrogen peroxide and interleukin-1ß levels were significantly reduced only in AOX rats. Data obtained suggest that early antioxidant supplementation improves cancer anorexia, ameliorates oxidative stress and reduces inflammation.
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Anorexia/tratamento farmacológico , Antioxidantes/uso terapêutico , Suplementos Nutricionais , Ingestão de Energia/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Sarcoma/complicações , Animais , Anorexia/sangue , Anorexia/etiologia , Antioxidantes/administração & dosagem , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/uso terapêutico , Peso Corporal/efeitos dos fármacos , Dieta , Modelos Animais de Doenças , Esquema de Medicação , Peróxido de Hidrogênio/sangue , Interleucina-1beta/sangue , Masculino , Metilcolantreno , Distribuição Aleatória , Ratos Endogâmicos F344 , Sarcoma/sangue , Sarcoma/induzido quimicamente , Vitamina E/administração & dosagem , Vitamina E/uso terapêuticoRESUMO
OBJECTIVES: We assessed the effects of oral immunonutrition (OI) on the inflammatory infiltration of the tumor microenvironment (TME) of patients undergoing surgery for gastric cancer. METHODS: We analyzed patients at the time of their first gastric cancer diagnosis. We collected surgical tissue specimens (stomach), and performed an immunohistochemical analysis to evaluate the inflammatory infiltration of the TME. Patients receiving OI were compared with patients receiving standard oral nutritional supplements and no nutritional support. RESULTS: We enrolled 12 patients with gastric cancer in the study. The median body weight loss was 5.6%. Four patients received OI, five patients received standard nutritional supplement, and three patients received no nutritional supplementation. No difference in age, body mass index (BMI), and body weight loss was observed between the three groups. The OI group showed a tendency of increased number of T-lymphocyte cluster of differentiation (CD) 8+ compared with the other groups, as well as the number of CD83+ and CD68+. The absence of F4/80+ cells was documented only in the TME of the OI group, where a linear positive correlation was present between lymphocytes CD4+ and CD8+ (R = 0.48), and between CD4+ and CD83+ (R = 0.89), although not statistically significant. In the OI group, we observed a positive correlation (not significant) between the number of lymphocytes CD8+ and macrophages CD68+ (R = 0.70; P = 0.30). A strong significant correlation was documented between CD68+ and CD40+ (R = 0.99; P = 0.01), but this correlation did not reach the significance among the patients of the other two groups (R = 0.60; P = 0.116). CONCLUSIONS: The administration of OI in patients with gastric cancer might determine changes in inflammatory patterns of the TME.
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Neoplasias Gástricas , Humanos , Neoplasias Gástricas/cirurgia , Microambiente Tumoral , Apoio Nutricional , Suplementos Nutricionais , Redução de PesoRESUMO
Arterial tortuosity syndrome (ATS) is a very rare autosomal recessive disorder that affects the connective tissue. The incidence of ATS is not well known and to date only 106 patients have been described in the literature. ATS affects medium and large size arteries, leading to widespread elongation and intensification of the average vessel tortuousness, responsible of several loops and kinks. Like other connective tissue disorders, ATS can present with joint laxity, hernias, pectus excavatum, scoliosis or other musculoskeletal abnormalities, and ocular defects. Due to the extreme variability of clinical symptoms and the fact that ATS has no curative management, prompt diagnosis is of tremendous importance to prevent disease-associated complications. In this situation, imaging techniques have a central role. In this study, we describe a rare case of a male newborn with tortuosity and lengthening of the main arterial and venous medium and large caliber branches with associated aortic coarctation who passed away prematurely. The finding of aortic coarctation in a newborn with ATS has rarely been described in the literature.
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Diagnosis in children with physical and intellective anomalies is very challenging because of the wide spectrum of causes. Array-based comparative genomic hybridization (CGH) has acquired an important role in pediatric diagnostic work up. Interstitial deletion of the long arm of chromosome 12 are rare. To date, deletions including the 12q21 region were reported in only 13 patients. The main features are development delay, eyes and central nervous system anomalies, and heart and kidney defects. We describe a 3-year-old boy with a de novo 15 Mb deletion at 12q21.1q21.32, never reported in the last cases. By screening the critical region and reviewing the literature, we identified SYT1, PPP1R12A, and CEP290 such as pathogenetic genes.
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Background: Guillain-Barrè syndrome (GBS) is an acute immune-mediated disorder affecting peripheral nerves and nerve roots with a variable clinical course and outcome. Epidemiologic analyses have revealed that the incidence of the syndrome increases linearly among the age. The clinical diagnosis of GBS is based on the family history, physical and neurological examination, electrodiagnostic exams, and cerebrospinal fluid analysis with the classical presence of albumin-cytologic dissociation. Prognosis is associated with the severity of clinical signs and the type of peripheral nerves involved. Methods: This study aims to clarify which clinical features can be used for prognostic purposes. We evaluated the correlation between (1) brain MRI lesions and grade of disability; (2) brain MRI lesions and elevated cerebrospinal fluid (CSF) protein; and (3) increased levels of CSF protein and grade of disability. Statistical analysis extracted from these data indicated a good correlation to be a prognostic indicator in children affected by GBS. We found little evidence regarding laboratory tests, imaging, and prognosis. We enrolled 12 continuous patients who met the Brighton criteria for GBS in this retrospective study. Each patient was clinically evaluated at the time of disease onset to assess the GBS disability score and after 2 weeks. Results: We estimated Pearson's correlation index to evaluate the possible correlation between MRI and disability and CSF protein levels and disability. The correlation coefficient was 0.92 and 0.85, respectively. In addition, we developed a graph to see the trend of the disability values, proteins in the CSF, and damage assessed with MRI in the 12 patients. It seems that these parameters have a parallel trend and a good correlation in each patient. Finally, we calculated the correlation between MRI and CSF protein values, with an r-value of 0.87. The values suggest a correlation among the MRI score, CSF protein, and prognosis. Conclusion: The MRI and CSF laboratory parameters can be important tools for the clinician not only for diagnosis but also to evaluate the possible worsening of general conditions or the need to prepare measures to support life parameters. Patients who need ventilatory support could be established early from patients who have less severe GBS and can begin rehabilitation earlier. We suggest MRI should be performed routinely in children with GBS to be able to estimate the evolution of the clinical condition.
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Connective tissue diseases (CTDs) include a spectrum of disorders that affect the connective tissue of the human body; they include autoimmune disorders characterized by immune-mediated chronic inflammation and the development of fibrosis. Lung involvement can be misdiagnosed, since pulmonary alterations preceded osteo-articular manifestations only in 20% of cases and they have no clear clinical findings in the early phases. All pulmonary structures may be interested: pulmonary interstitium, airways, pleura and respiratory muscles. Among these autoimmune disorders, rheumatoid arthritis (RA) is characterized by usual interstitial pneumonia (UIP), pulmonary nodules and airway disease with air-trapping, whereas non-specific interstitial pneumonia (NSIP), pulmonary hypertension and esophageal dilatation are frequently revealed in systemic sclerosis (SSc). NSIP and organizing pneumonia (OP) may be found in patients having polymyositis (PM) and dermatomyositis (DM); in some cases, perilobular consolidations and reverse halo-sign areas may be observed. Systemic lupus erythematosus (SLE) is characterized by serositis, acute lupus pneumonitis and alveolar hemorrhage. In the Sjögren syndrome (SS), the most frequent pattern encountered on HRCT images is represented by NSIP; UIP and lymphocytic interstitial pneumonia (LIP) are reported with a lower frequency. Finally, fibrotic NSIP may be the interstitial disease observed in patients having mixed connective tissue diseases (MCTD). This pictorial review therefore aims to provide clinical features and imaging findings associated with autoimmune CTDs, in order to help radiologists, pneumologists and rheumatologists in their diagnoses and management.
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In children with developmental delay (DD) and neurologic impairment, diagnosis can be challenging because of the wide spectrum of causes. Since the last decade, the use of array comparative genomic hybridization (CGH) offered a great contribution to get a diagnosis in complex phenotypes. The chromosome 7 is subject of interest in medical genetics because of its frequent association with chromosome aberrations, rearrangements, and deletions involving clinical manifestations. We hereby reported a 3-year-old male child patient with severe neuro-DD, craniofacial dysmorphisms, and pulmonary stenosis, whose array CGH analysis disclosed a duplication of 14.4 Mb on chromosome 7 (7q21.3-7q31.1). By reviewing the current literature to date, we first reported on neurologic and dysmorphic anomalies related to this rearrangement which was not previously reported.
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Vasculitides represent a heterogeneous group of immune-mediated disorders, characterized by a systemic inflammatory destructive process of the blood vessels resulting either in ischemia or hemorrhage. The organ involved and vessel size influence the pattern of presentation of the pathology. The lung is commonly involved in systemic vasculitides, with heterogeneous clinical, radiological, and histopathological presentations. Primary vasculitides most commonly associated with lung parenchymal involvement include small-vessel antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides, such as granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA). Several studies have reported cases of interstitial lung diseases (ILDs) associated with systemic vasculitis, particularly those positive for ANCA associated vasculitis/vasculitidis: AAV. We have selected from our case series different radiological features of pulmonary vasculitis (i.e., solitary or multiple nodules, cavitary lesions, nodules with centrilobular or peribronchial distribution, airspace consolidations, "crazy paving" appearance, interstitial disease), including cases with interstitial lung alterations. Therefore, the aim of this review is to describe the typical clinical manifestations of vasculitides and their main radiologic features (especially AAV).
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Non-traumatic hepatic hernia is defined as hepatic protrusion through acquired or congenital defects on diaphragm without prior trauma. This event is rare among adults and infrequently reported in literature. 52-year-old Caucasian woman with surgically treated breast cancer with suspected lung metastasis detected during a routine Multidetector Computed Tomography lung exam. Ultrasound and subsequently Magnetic Resonance Imaging (MRI) was performed which revealed an overdiaphragmatic mass in contiguity with liver parenchyma compatible with overdiaphragmatic hepatic hernia. Differential diagnosis should be made with diaphragmatic or pulmonary nodule. Correct diagnosis can avoid further diagnostic investigations or invasive procedures such as biopsy. Magnetic Resonance Imaging is a non-risky method and can clarify interpretative doubts. Currently there are still controversies about traumatic or idiopathic nature of this hernia.
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Wilkie's Syndrome is a very rare disease caused by reduction of aorto-mesenteric space with consequent duodenum compression. It can combine with left renal vein stenosis which, when symptomatic, is known as "Nutcracker Syndrome". We describe a clinical onset case with epigastric pain without vomiting in a normal weight patient. 28-year-old woman who came to our observation for intense epigastric pain after a weight loss of 14 kg in 4 months. Multidetector Computed Tomography and Ultrasound revealed gastric and duodenal overdistension with hydro-air levels, severe duodenum stenosis, and left renal vein compression. Wilkie's Syndrome is common in anorexic individuals suffering from recurrent postprandial vomiting, onset with severe epigastric pain, without vomiting, is quite unusual. High-calorie diet must be first therapeutic approach, in case of failure treatment of first choice should be endovascular stenting and, only in selected cases, surgical treatment should be used because it is very invasive and burdened with numerous complications. Failure to diagnose this disease can expose patients to serious health risks.
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BACKGROUND Since December 2019, an outbreak caused by a novel coronavirus infection (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) occurred in Wuhan, China, and it rapidly spread all over the world. The clinical spectrum of coronavirus disease 2019 (COVID-19) is wide, with acute respiratory distress syndrome (ARDS) occurring in 15% of patients affected, requiring high oxygen support. Currently, there is no clearly effective antiviral therapy. Steroids and immunomodulators are under investigation for potential activity. Little is known about middle and long-term sequelae on respiratory function. According to some authors, COVID-19 could cause pulmonary fibrosis. We report 3 cases of pulmonary fibrosis detected on follow-up computed tomography (CT) imaging in 3 female patients who recovered from COVID-19 pneumonia in Italy (L'Aquila, Abruzzo). CASE REPORT All patients were female and had no significant previous respiratory disease or history of smoke exposure, and none had received high-flow oxygen support during treatment of the disease. In all cases, late onset of mild dyspnea, slow and incomplete respiratory recovery, and early evidence of fibrous signs on chest CT scan were characteristic of the clinical course. CONCLUSIONS This report focuses on a possible scenario of long-term lung damage in COVID-19 pneumonia survivors. Limitations are lack of long-term follow-up and functional data in the very early phase. It is advantageous that all COVID-19 pneumonia patients undergo serial chest CT and spirometry long-term follow-up for at least 1 year to assess residual damage. This is particularly relevant in those with slow respiratory recovery and long hospitalization.
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COVID-19/diagnóstico , Pulmão/diagnóstico por imagem , Fibrose Pulmonar/diagnóstico , SARS-CoV-2 , Tomografia Computadorizada por Raios X/métodos , Idoso , Idoso de 80 Anos ou mais , COVID-19/complicações , COVID-19/epidemiologia , Feminino , Humanos , Pessoa de Meia-Idade , Pandemias , Fibrose Pulmonar/complicações , Radiografia TorácicaRESUMO
P. jiroveci (Pj) causes a potentially fatal pneumonia in immunocompromised patients and the factors associated with a bad outcome are poorly understood. A retrospective analysis on Pj pneumonia (PjP) cases occurring in Tor Vergata University Hospital, Italy, during the period 2011-2015. The patients' demographic, clinical and radiological characteristics and the Pj genotypes were considered. The study population included 116 patients, 37.9% of whom had haematological malignancy or underwent haematological stem cell transplantation (HSCT), 22.4% had HIV infection, 16.4% had chronic lung diseases (CLD), 7.8% had a solid cancer, and 3.4% underwent a solid organ transplant (SOT). The remaining 12.1% had a miscellaneous other condition. At univariate analysis, being older than 60 years was significantly correlated with a severe PjP (OR [95%CI] 2.52 [0.10-5.76]; p = 0.031) and death (OR [95%CI] 2.44 [1.05-5.70]; p = 0.036), while a previous trimethoprim/sulfamethoxazole (TMP/SMX) prophylaxis were significantly associated with a less severe pneumonia (OR[95%CI] 0.35 [0.15-0.84], p = 0.023); moreover, death due to PjP was significantly more frequent in patients with CLD (OR[95%CI] 3.26 [1.17-9.05]; p = 0.019) while, admission to the Infectious Diseases Unit was significantly associated with fewer deaths (OR[95%CI] 0.10 [0.03-0.36], p = 0.002). At multivariate analysis, a better PjP outcome was observed in patients taking TMP/SMX prophylaxis and that were admitted to the Infectious Diseases Unit (OR[95%CI] 0.27 [0.07-1.03], p = 0.055, OR[95%CI] 0.16 [0.05-0.55]; p = 0.004, respectively). In conclusion, in our study population, TMP/SMX prophylaxis and infectious disease specialist approach were variables correlated with a better PjP outcome.
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Infecções por HIV/epidemiologia , Admissão do Paciente , Quartos de Pacientes , Pneumocystis carinii , Pneumonia por Pneumocystis/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Doenças Transmissíveis , Comorbidade , Feminino , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Soropositividade para HIV , Humanos , Hospedeiro Imunocomprometido , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Razão de Chances , Avaliação de Resultados em Cuidados de Saúde , Pneumocystis carinii/classificação , Pneumocystis carinii/genética , Pneumocystis carinii/isolamento & purificação , Pneumonia por Pneumocystis/diagnóstico , Pneumonia por Pneumocystis/tratamento farmacológico , Pneumonia por Pneumocystis/etiologia , Estudos Retrospectivos , Fatores de Risco , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
OBJECTIVE: Glioblastoma multiforme (GBM) develops from a small subpopulation of stem-like cells, which are endowed with the ability to self-renew, proliferate and give rise to progeny of multiple neuroepithelial lineages. These cells are resistant to conventional chemo- and radiotherapy and are hence also responsible for tumor recurrence. HMGA1 overexpression has been shown to correlate with proliferation, invasion, and angiogenesis of GBMs and to affect self-renewal of cancer stem cells from colon cancer. The role of HMGA1 in GBM tumor stem cells is not completely understood. RESEARCH DESIGN AND METHODS: We have investigated the role of HMGA1 in brain tumor stem cell (BTSC) self-renewal, stemness and resistance to temozolomide by shRNA- mediated HMGA1 silencing. RESULTS: We first report that HMGA1 is overexpressed in a subset of BTSC lines from human GBMs. Then, we show that HMGA1 knockdown reduces self-renewal, sphere forming efficiency and stemness, and sensitizes BTSCs to temozolomide. Interestingly, HMGA1 silencing also leads to reduced tumor initiation ability in vivo. CONCLUSIONS: These results demonstrate a pivotal role of HMGA1 in cancer stem cell gliomagenesis and endorse HMGA1 as a suitable target for CSC-specific GBM therapy.
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Neoplasias Encefálicas/patologia , Glioblastoma/genética , Proteína HMGA1a/genética , Células-Tronco Neoplásicas/metabolismo , Antineoplásicos Alquilantes/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Linhagem Celular Tumoral , Dacarbazina/análogos & derivados , Dacarbazina/farmacologia , Resistencia a Medicamentos Antineoplásicos , Técnicas de Silenciamento de Genes , Inativação Gênica , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Humanos , RNA Interferente Pequeno/genética , TemozolomidaRESUMO
Cachexia is a clinically relevant syndrome which impacts on quality of life, morbidity and mortality of patients suffering from acute and chronic diseases. The hallmark of cachexia is muscle loss, which is triggered by disease-associated inflammatory response. Cachexia is a continuum and therefore a staging system is needed. Initially, a three-stage system (i.e. pre-cachexia, cachexia and refractory cachexia) was proposed. More recent evidence supports the use of a five-stage classification system, based on patient's BMI and severity of weight loss, to better predict clinical outcome. Also, large clinical trials in cancer patients demonstrated that cachexia emerging during chemotherapy has greater influence on survival than weight loss at baseline. Therefore, becoming widely accepted is the importance of routinely monitoring patients' nutritional status to detect early changes and diagnose cachexia in its early phases. Although cachexia is associated with the presence of anabolic resistance, it has been shown that sustained yet physiological hyperaminoacidaemia, as well as the use of specific nutrients, is able to overcome impaired protein synthesis and revert catabolism. More importantly, clinical evidence demonstrates that preservation of nutritional status during chemotherapy or improvement of body weight after weight loss is associated with longer survival in cancer patients.
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Índice de Massa Corporal , Caquexia/etiologia , Inflamação/etiologia , Desnutrição/etiologia , Atrofia Muscular/etiologia , Neoplasias/complicações , Redução de Peso , Aminoácidos/uso terapêutico , Caquexia/classificação , Caquexia/dietoterapia , Humanos , Estado Nutricional , Biossíntese de ProteínasRESUMO
BACKGROUND: Weaning from tracheostomy has implications in management, quality of life, and costs of ventilated patients. Furthermore, endotracheal cannula removing needs further studies. Aim of this study was the validation of a protocol for weaning from tracheostomy and evaluation of predictor factors of decannulation. METHODS: Medical records of 48 patients were retrospectively evaluated. Patients were decannulated in agreement with a decannulation protocol based on the evaluation of clinical stability, expiratory muscle strength, presence of tracheal stenosis/granulomas, deglutition function, partial pressure of CO2, and PaO2/FiO2 ratio. These variables, together with underlying disease, blood gas analysis parameters, time elapsed with cannula, comordibity, Barthel index, and the condition of ventilation, were evaluated in a logistic model as predictors of decannulation. RESULTS: 63 % of patients were successfully decannulated in agreement with our protocol and no one needed to be re-cannulated. Three variables were significantly associated with the decannulation: no pulmonary underlying diseases (OR = 7.12; 95 % CI 1.2-42.2), no mechanical ventilation (OR = 9.55; 95 % CI 2.1-44.2) and period of tracheostomy ≤10 weeks (OR = 6.5; 95 % CI 1.6-27.5). CONCLUSIONS: The positive course of decannulated patients supports the suitability of the weaning protocol we propose here. The strong predictive role of three clinical variables gives premise for new studies testing simpler decannulation protocols.
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INTRODUCTION: Ambulatory oxygen (O2) is prescribed to interstitial lung disease (ILD) patients with mild hypoxemia, breathlessness and dyspnea on exertion. Oxygen titration is generally done with the 6 minute walk test (6MWT) to determine the O2 flow preventing oxygen saturation by pulse oximetry (SpO2) from falling below 88%. His study was designed to generate a 6MWT index predicting the O2 flow allowing completion of the 6MWT without oxygen desaturation. METHODS: Oxygen titration data from a group of 66 ILD patients and 30 controls, were used to generate the algorithm determining an index (O2-GAP) predicting oxygen flow required to complete a 6MWT without desaturation below 88%. This index was validated in a group of 93 ILD patients. RESULTS: The O2-GAP index, as obtained from the derivation population, (r(2) = 0.97, p < 0.001) was shown to correctly predict the oxygen flow required to complete the 6MWT without SpO2 falling below 88% validated in the validation population (r(2) = 0.842; p < 0.001). CONCLUSIONS: The O2-GAP index appears to be a useful tool to titrate ambulatory O2 with a single 6MWT on room air in ILD patients with breathlessness and dyspnea on exertion.