Non-respiratory Diseases Research Articles

An uncommon cause of hemoptysis: aortobronchial fistula

BackgroundHemoptysis is a frequent sign of respiratory and non-respiratory diseases. While in most cases the underlying cause is rapidly identified, sometimes the real etiology might be misdiagnosed with dramatic delay in treatment.Case presentationA 46-year-old man with hiatal hernia and a history of aortic surgery for aortic coarctation presented with dramatic episodes of hemoptysis and subsequent severe anemia (6,9 g/dl). Digestive and respiratory endoscopy resulted not exhaustive, thus he underwent a contrast-enhanced computed tomography (CT) scan of the chest that showed an aneurysmal dilatation of the descending thoracic aorta with suspected aortobronchial fistula. He underwent cardiac surgery that confirmed the diagnosis and successfully treated the fistula.ConclusionWe briefly review the literature to raise clinical awareness on this uncommon cause of hemoptysis.

An uncommon cause of hemoptysis: aortobronchial fistula

Background: Hemoptysis is a frequent sign of respiratory and non-respiratory diseases. While in most cases the underlying cause is rapidly identified, sometimes the real etiology might be misdiagnosed with dramatic delay in treatment. Case presentation: A 46-year-old man with hiatal hernia and a history of aortic surgery for aortic coarctation presented with dramatic episodes of hemoptysis and subsequent severe anemia (6,9 g/dl). Digestive and respiratory endoscopy resulted not exhaustive, thus he underwent a contrast-enhanced computed tomography (CT) scan of the chest that showed an aneurysmal dilatation of the descending thoracic aorta with suspected aortobronchial fistula. He underwent cardiac surgery that confirmed the diagnosis and successfully treated the fistula. Conclusion: We briefly review the literature to raise clinical awareness on this uncommon cause of hemoptysis.

Mild-to-moderate hemoptysis: a diagnostic and clinical challenge.

Mild-to-moderate hemoptysis is defined as the expectoration of blood or blood-streaked sputum originating from the lower respiratory tract, in volumes that do not immediately threaten the patient's life. Nevertheless, it is a very common respiratory symptom and the list of underlying respiratory or non-respiratory diseases is vast, ranging from the most worrying to more easily manageable etiologies. In this narrative review, we have analyzed the most recent recommendations inferred from the literature, in terms of diagnostic as well as therapeutic approach.

Surfactant Protein D in Respiratory and Non-Respiratory Diseases.

Surfactant protein D (SP-D) is a multimeric collectin that is involved in innate immune defense and expressed in pulmonary, as well as non-pulmonary, epithelia. SP-D exerts antimicrobial effects and dampens inflammation through direct microbial interactions and modulation of host cell responses via a series of cellular receptors. However, low protein concentrations, genetic variation, biochemical modification, and proteolytic breakdown can induce decomposition of multimeric SP-D into low-molecular weight forms, which may induce pro-inflammatory SP-D signaling. Multimeric SP-D can decompose into trimeric SP-D, and this process, and total SP-D levels, are partly determined by variation within the SP-D gene, SFTPD. SP-D has been implicated in the development of respiratory diseases including respiratory distress syndrome, bronchopulmonary dysplasia, allergic asthma, and chronic obstructive pulmonary disease. Disease-induced breakdown or modifications of SP-D facilitate its systemic leakage from the lung, and circulatory SP-D is a promising biomarker for lung injury. Moreover, studies in preclinical animal models have demonstrated that local pulmonary treatment with recombinant SP-D is beneficial in these diseases. In recent years, SP-D has been shown to exert antimicrobial and anti-inflammatory effects in various non-pulmonary organs and to have effects on lipid metabolism and pro-inflammatory effects in vessel walls, which enhance the risk of atherosclerosis. A common SFTPD polymorphism is associated with atherosclerosis and diabetes, and SP-D has been associated with metabolic disorders because of its effects in the endothelium and adipocytes and its obesity-dampening properties. This review summarizes and discusses the reported genetic associations of SP-D with disease and the clinical utility of circulating SP-D for respiratory disease prognosis. Moreover, basic research on the mechanistic links between SP-D and respiratory, cardiovascular, and metabolic diseases is summarized. Perspectives on the development of SP-D therapy are addressed.

ADVANCEMENTS IN DRY POWDER INHALER

The dry powder inhaler (DPI) has become widely known as a very attractive platform for drug delivery. DPIs are being used for the treatment of asthma and chronic obstructive pulmonary disease by many patients. There are over 20 devices presently in the DPI market. DPIs are preferred over nebulizers and pressurized metered dose inhalers. However, some of the challenges of DPI are dependence on inspiratory flow (unsuitable for young children, elderly people), systemic absorption due to deposition of drug in deep lung (unsuitable for local diseases treatment), and increase in upper airway deposition of a large fraction of coarse particles. Hence, there is a need to address these unmet issues. The interpatient variation can be minimized by developing devices independent of patient’s inspiratory flow rate or active based powder mechanism. This article reviews DPI devices currently available, advantages of newly developed devices, and formulation technologies. The platform technologies are developed to improve aerosolization and dispersion from the device and decrease the patient related factors. The DPI delivery system has been expanded to treatment of non-respiratory diseases such as migraine and diabetes. The development of innovative DPI device and formulation technologies for delivering therapeutic proteins such as insulin has been accelerated to overcome the problems associated with conventional insulin therapy.Keywords: Dry powder inhaler, Inspiratory flow rate, Insulin, Platform technologies.

Squat-to-stand test in functional assessment of stable chronic obstructive pulmonary disease patients.

Background:Assessment of functional status is vital for proper therapy and rehabilitation programs in chronic obstructive pulmonary disease (COPD) patients. Traditionally, 6 min walk test (6MWT) has been used but it by itself may not reflect the total functional status in these patients as it poorly correlates to the disease severity. A sit-to-stand test (STST) has been proposed as a better alternative to 6MWT but to test their ability to stand from the squatting position, i.e., a squat-to-stand test (SqTST) will be more appropriate in rural patients.Material and Methods:All patients, diagnosed to have stable COPD, after exclusion of asthma and other respiratory or nonrespiratory diseases were evaluated by applying 6MWT, STST, and SqTST in them. Data so obtained were statistically analyzed.Results:Ninety patients and twenty healthy controls were studied. Sixteen, 24, 23, and 27 of the patients were classed as COPD risk category A, B, C, and D, respectively. The mean post bronchodilator forced expiratory volume in 1st second (PB FEV1) and body mass index (BMI) were significantly lower in category D as compared to the rest. The cutoff values for 6MWT, STST, and SqTST were derived as 184M, 11, and 07, respectively. 6MWT correlates poorly to disease severity (P = 0.109) but there was a strong correlation between disease severity and SqTST and STST (P = 0.000).Conclusion:SqTST is a feasible and effective tool to assess functional status of COPD patients residing in rural areas. BMI is an important surrogate marker of the functional status in these patients.

Free asthma medications reduces hospital admissions in Brazil (Free asthma drugs reduces hospitalizations in Brazil)

BackgroundSince June 2011, the Brazilian health system started providing asthma medications (beclomethasone and salbutamol), totally free of charge to patients with asthma. The aim of this study was to evaluate the impact of the provision of free asthma medications on hospital admissions for asthma in Brazil, using a national hospitalization database (DATASUS), comparing the incidence of hospital admissions before and after the free supply of these drugs. MethodsAdmissions of patients with 1–49 years of age by the Brazilian public health system with the diagnosis of asthma were compared pre (2008–2010) and post (2012–2014) provision of free medicines (beclomethasone and salbutamol). The number of hospital admissions due to asthma and non-respiratory diseases, as well as the amount spent with asthma hospitalization, were obtained from DATASUS, the Brazilian government open-access public health database system. ResultsAdmission rates for asthma significantly decreased from 90.09/100.000 (2008–2010) to 59.85/100.000 (2012–2014), when the period pre and post provision of free medicines were compared [OR 0.67 (CI 0.48–0.92)]. Non-respiratory admission rates remained stable, when both periods were also compared. ConclusionAsthma hospitalization rates significantly decreased in the three-year period after the provision of free medicines to treat asthma. Our findings suggest that the provision of free medications for asthma may have a particular public health impact by its own in developing countries.

Comparison of Arterial and Venous Blood Gas Measurements in Non-Respiratory Diseases Patients Admitted in Intensive Care Unit (ICU)

The aim is to study the relationship between arterial and venous blood gas measurements of pH, HCO3 - & pCO2 in patients of non-respiratory diseases admitted in ICU in PCMS&RC, Bhopal. Enrollment of non-respiratory disease patients admitted in ICU reporting in our hospital to evaluate the relationship between arterial and venous blood gas parameters through Cross-sectional Study. The data we reviewed revealed us that venous blood gas analysis has the potential to be of great importance in the ICU setting in general as well as for patients presenting with different diagnosis. The association between Arterial and venous pH in which p-value of 0.85 which is not significant. The association between Arterial and venous pO2 in which the p-value of 0.001 which is highly significant. The association between Arterial and venous pCO2 in which p-value of 0.001 which is highly significant. The association between Arterial and venous HCO3 - in which p-value of 0.056 which is not significant. Correlation between arterial and venous parameters reveals all the correlation coefficient (r) is positive and only pH, pCO2 and HCO3 - are highly significant. The use of venous blood gas values has shown to be cost-effective and implementation of this procedure in the routine venous blood sampling will prove to be time and money saving as well, as it will reduce the risk factors for the patient and the health care worker. The venous blood gas values for pH and HCO3 - showed excellent association and correlation and can

A Case-control Study of Diphtheria in the High Incidence City of Hyderabad, India.

India accounts for approximately 72% of reported diphtheria cases globally, the majority of which occur in the state of Andhra Pradesh. The aim of this study is to better understand lack of knowledge on diphtheria vaccination and to determine factors associated with diphtheria and low knowledge and negative attitudes. We performed a 1:1 case-control study of hospitalized diphtheria cases in Hyderabad. Eligible case patients were 10 years of age or older, resided within the city of Hyderabad and were diagnosed with diphtheria per the case definition. Patients admitted to the hospital for nonrespiratory communicable diseases and residing in the same geographic region as that of cases were eligible for enrolment as controls : There were no statistical differences in disease outcome by gender, education, economic status and mean room per person sleeping in the house in case and control subjects. Not having heard of diphtheria (adjusted odds ratio: 3.56; 95% confidence intervals: 1.58-8.04] and not believing that vaccines can prevent people from getting diseases (adjusted odds ratio: 3.99; 95% confidence intervals: 1.18-13.45) remained significantly associated with diphtheria on multivariate analysis. To reduce the burden of diphtheria in India, further efforts to educate the public about diphtheria should be considered.

Respiratory Tract Infection Clinical Trials from 2007 to 2012. A Systematic Review of ClinicalTrials.gov.

Respiratory tract infections are highly prevalent and variable, and confer considerable morbidity and mortality. There is a growing need for new treatments for such infections, particularly in the setting of worsening antibacterial resistance. We analyzed data from ClinicalTrials.gov to summarize activity in respiratory infection trials, identify gaps in research activity, and inform efforts to address disparities between antimicrobial resistance and development of new antibacterial drugs. We examined 69,779 interventional trials registered with ClinicalTrials.gov from 2007 to 2012, focusing on study conditions and interventions to identify respiratory infection-related trials. Programmatic identification with manual confirmation yielded 6,253 infectious disease trials, 1,377 respiratory infection trials, and 270 lower respiratory tract infection trials for analysis. The 1,377 respiratory infection trials accounted for 2% of all trials and 22% of infectious diseases trials. Such trials (54.8%) were more likely than either nonrespiratory infectious diseases trials (48.1%) or noninfectious disease trials (42.8%) to receive industry funding. Stratification of respiratory infection trials by registration year demonstrated declining industry funding: 181 (64.9%) in 2007-2008 to 110 (46.0%) in 2011-2012. Respiratory infection trials more frequently evaluated vaccines (52.7 vs. 15.5% of nonrespiratory tract infection trials). Lower respiratory tract infection trials (excluding tuberculosis) focused primarily on bacterial pathogens (78.5%) followed by viral (12.6%), fungal (5.6%), and nontuberculous mycobacterial (3.0%) pathogens. Approximately 40% of 120 lower respiratory tract infection trials that were completed or terminated published results in the literature. On multivariable logistic regression analysis, a treatment focus was associated with decreased odds of publishing results (odds ratio, 0.28; 95% confidence interval, 0.10-0.82; P = 0.02). There were also generally low numbers of studies evaluating novel antimicrobial agents (community-acquired pneumonia, 15.9%; hospital-acquired pneumonia, 16.7%; ventilator-associated pneumonia, 5.3%). From 2007 to 2012, respiratory infection trials did not occur in numbers commensurate with global impact. The number of trials registered per year did not increase throughout the study period, partly due to declining industry support. There was a concerning reduction in prevention-oriented lower respiratory infection trials and an overall low number of such trials involving novel antimicrobials.

Casos clínicos de eficacia y seguridad del fentanilo intranasal con pectina en Oncología Médica

Cancer pain is a complex and highly important problem in daily clinical practice. Although cancer is usually painless in the early phases of its development, the prevalence of chronic pain is 30%-50% in cancer patients undergoing active treatment and 79%-90% in patients with advanced disease. The true prevalence of breakthrough cancer pain is unclear and varies widely across studies, ranging from 19% to 93%. Dyspnea is a highly frequent symptom that is common to many diseases, indicating its multisystemic origin. This symptom can occur in respiratory and non-respiratory diseases. Dyspnea is present in up to 78% of patients with lung cancer. We describe two clinical cases in which fentanyl pectin nasal spray was used in the management of both breakthrough cancer pain and dyspnea exacerbations, providing strong symptomatic relief in both patients.

A Cough of Unknown Origin: An Often Serious, Unmet Clinical Problem

Coughing is a common symptom present in primary care. Results of epidemiologic surveys suggest that only a small fraction of patients with a cough seek medical care for this symptom. Typically, symptoms that have no identified cause such as the cough of unknown origin (CUO) is a serious clinical problem in internal medicine and is all too often connected to allergy backgrounds. Coughing in itself is a problem regardless of either a causative condition identified as asthma, chronic obstructive pulmonary disease (COPD), or gastroesophageal reflux, or its origin remains unknown. This article reviews our current understanding of the pathogenesis of coughing that characterizes a number of respiratory and non-respiratory diseases. A more in-depth knowledge in this field of international medicine is a condition for a more targeted clinical approach to the patient with CUO and helps contain health care costs while providing unquestionable benefits to the community. Finally, it is reported the most recent approach for the CUO’s treatment.

Hospitalization Due to Co-Morbid Conditions is the Main Cost Driver Among Subjects With COPD–A Report From the Population-Based OLIN COPD Study

Background: Co-morbidities are common in COPD; however, there is a lack of population-based studies evaluating the health economic impact of co-morbid diseases for subjects with COPD. The main objective of this study was to estimate annual direct health-care costs, divided into costs due to non-respiratory and respiratory conditions, comparing subjects with and without COPD. Methods: Subjects with and without COPD derived from population-based cohorts in northern Sweden have been invited to annual examinations involving spirometry and structured interviews since 2005. This paper is based on data from 1472 subjects examined in 2006. COPD classification was based on spirometry. Results: Mean annual costs for both respiratory and non-respiratory conditions were significantly higher for subjects with COPD than non-COPD subjects, in total USD 2139 vs. USD 1276 (p = 0.026), and COPD remained significantly associated with higher costs also after adjustment for common confounders as age, smoking habits, BMI and sex. The mean total cost increased with COPD disease severity and was higher for all severity stages (GOLD) than for non-COPD subjects. Hospitalization due to non-respiratory diseases was the main cost driver in COPD, after adjustment for common confounders amounting to about 46% (unadjusted 62%) of the total COPD-costs. Conclusions: Costs were higher for COPD than non-COPD. In COPD, costs for co-morbid conditions were higher than those for respiratory conditions, and hospitalization due to co-morbid conditions was the main cost driver also when adjusted for common confounders.

Early-life risk factors for chronic nonrespiratory diseases.

We have witnessed a change in disease patterns contributing to the global burden of disease, with a shift from early childhood deaths due to the classic infectious communicable diseases to years lived with disability from chronic noncommunicable diseases. In both developing and developed countries, the years lived with disability attributable to chronic disease have increased: cardiovascular diseases by 17.7%; chronic respiratory disease by 8.5%; neurological conditions by 12.2%; diabetes by 30.0%; and mental and behavioural disorders by 5.0% over the past 20 years. Recognition of the contribution made by adverse environmental exposures in early life to noncommunicable diseases in later life is increasing. These early-life exposures appear to contribute to both chronic respiratory and chronic nonrespiratory diseases. In this State of the Art article, we aim to examine early-life environmental exposures that have an epidemiological association with chronic nonrespiratory diseases, such as obesity and type II diabetes, cardiovascular disease, and neurocognitive and behavioural problems. We will highlight the potential overlap in environmental risks with respiratory diseases, and point out knowledge gaps and research opportunities.

Emergence of serogroup 15 Streptococcus pneumoniae of diverse genetic backgrounds following the introduction of pneumococcal conjugate vaccines in Hong Kong

Serogroup 15 pneumococcal isolates from nasopharyngeal carriage of hospitalized children admitted to a teaching hospital in Hong Kong from April 2009 to September 2013 were characterized by pulse-field gel electrophoresis (PFGE), multilocus sequence typing, and antimicrobial non-susceptibility testing. The overall proportion of serogroup 15 isolates in the pre-PCV7 and post-PCV13 periods rose from 5.7% to 20.0%. The increase in trend for serotype 15B/C was statistically significant among children presented with pneumonia; bronchiolitis; upper respiratory tract infection; and febrile, non-respiratory diseases and for serotype 15A/F, among children with bronchiolitis and febrile, non-respiratory diseases. The predominant PFGE cluster of serotype 15B/C belonged to sequence type (ST) 199. Replacement of this more susceptible cluster (Ery and Tet non-susceptibilities of 32.2% and 25.4%) with the non-susceptible cluster, ST8859 (Ery and Tet non-susceptibilities of 91.7% and 87.5%) was noted. ST63 was the predominant serotype 15A cluster (Ery and Tet non-susceptibilities of 97.4% and 92.3%). Serogroup 15 subtypes have emerged in the post-PCV13 era, and these non-susceptible clusters warrant closer monitoring as candidates for incorporation to future pneumococcal vaccines.

Oxidative stress and free radicals in COPD--implications and relevance for treatment.

Oxidative stress occurs when free radicals and other reactive species overwhelm the availability of antioxidants. Reactive oxygen species (ROS), reactive nitrogen species, and their counterpart antioxidant agents are essential for physiological signaling and host defense, as well as for the evolution and persistence of inflammation. When their normal steady state is disturbed, imbalances between oxidants and antioxidants may provoke pathological reactions causing a range of nonrespiratory and respiratory diseases, particularly chronic obstructive pulmonary disease (COPD). In the respiratory system, ROS may be either exogenous from more or less inhalative gaseous or particulate agents such as air pollutants, cigarette smoke, ambient high-altitude hypoxia, and some occupational dusts, or endogenously generated in the context of defense mechanisms against such infectious pathogens as bacteria, viruses, or fungi. ROS may also damage body tissues depending on the amount and duration of exposure and may further act as triggers for enzymatically generated ROS released from respiratory, immune, and inflammatory cells. This paper focuses on the general relevance of free radicals for the development and progression of both COPD and pulmonary emphysema as well as novel perspectives on therapeutic options. Unfortunately, current treatment options do not suffice to prevent chronic airway inflammation and are not yet able to substantially alter the course of COPD. Effective therapeutic antioxidant measures are urgently needed to control and mitigate local as well as systemic oxygen bursts in COPD and other respiratory diseases. In addition to current therapeutic prospects and aspects of genomic medicine, trending research topics in COPD are presented.

Impact of 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) on childhood pneumonia hospitalizations in Brazil two years after introduction

IntroductionPneumococcal disease is a major public health problem worldwide. From March to September of 2010, 10-valent pneumococcal non-typeable Haemophilus influenzae protein conjugate vaccine (PHiD-CV) was introduced in the Brazilian childhood National Immunization Program (NIP) in all 27 Brazilian states. The aim of the present study is to report national time-trends in incidence of hospital admissions for childhood pneumonia in Brazil before and after two years of introduction of this new pneumococcal conjugate vaccine. MethodsAnalysis of hospitalization data of children aged 0–4 years in Brazilian public health system with an admission diagnosis of pneumonia from 2002 to 2012 was performed comparing pre (2002–2009) and post-vaccination periods (2011–2012). Hospital number of admission due to pneumonia and all non-respiratory diseases were obtained from DATASUS, the Brazilian government open-access public health database system. Incidence of pneumonia hospitalization was compared to incidence of all non-respiratory admissions. ResultsAdmission rates for pneumonia decreased steadily from 2010 to 2012. In children aged less than four years, incidence of pneumonia hospitalizations decreased 12.65% when pre (2002–2009) and post-vaccination introduction periods (2011–2012) were compared and adjusted for seasonality and secular-trend (p<0.001). On the other hand, non-respiratory admission rates remained stable comparing both periods (p=0.39). ConclusionChildhood pneumonia hospitalization rates were fluctuating prior to 2010 and decreased significantly in the two years after PHiD-CV introduction. Conversely, rate of non-respiratory admissions has shown no decrease. These data are an evidence of the effectiveness and public health impact of this new pneumococcal vaccine.

Chronic Domiciliary Oxygen Therapy–Year SEPAR

Oxygen was the “rst treatment shown to increase survival in patients with chronic obstructive pulmonary disease (COPD). Current recommendations for the prescription of continuous domiciliary oxygen therapy (CDO) are based on the results of 2 clinical trials published over 30 years ago: the Nocturnal Oxygen Therapy Trial (NOTT) and the Medical Research Council (MRC) study. 1,2 CDO is indicated in patients with COPD and resting PaO2 �55 mmHg or resting PaO2 between 56 and 59 mmHg with evidence of chronic pulmonary hypertension or polycythemia. Based on the hypothesis that the bene“cial effect of oxygen is a result of the correction of hypoxemia, irrespective of the cause, this indication has been extended by analogy to chronic respiratory failure caused by other respiratory (idiopathic pulmonary “brosis, cystic “brosis, etc.) and non-respiratory diseases (heart failure). However, the effectiveness of continuous oxygen therapy on survival in these other disease entities has not been demonstrated, and studies justifying indication in these cases are required. 3 In contrast with the results of the MRC or NOTT clinical trials, supplementary oxygen has not been shown to improve survival in patients with COPD and moderate hypoxemia. 4 However, these studies have been criticized for reporting a small number of patients, an inappropriately short study period and inadequate average daily administration of oxygen–approximately 13.5 h, clearly insuf“cient for showing effects on mortality. It is known, for example, that patients with COPD and chronic respiratory failure receiving CDO have a rebound effect, with pulmonary vascular resistance increasing when oxygen is suspended for periods as short as 3 h a day. Moreover, it is clear that the mortality rate in COPD patients with comorbidities is higher. Nevertheless, none of the studies analyzing the effects of CDO evaluate the in”uence of comorbidities in general or of cardiovascular disease in particular. It is currently unclear if continuous oxygen therapy reduces metabolic and/or cardiovascular death in hypoxemic COPD patients. Current guidelines do not provide any indications for “pure” patients (with no associated comorbidities), and the therapeutic effects of CDO are analyzed in groups that are poorly representative of COPD patients. 5

Continuous Home Oxygen Therapy

Oxygen therapy is defined as the therapeutic use of oxygen and consists of administering oxygen at higher concentrations than those found in room air, with the aim of treating or preventing hypoxia. This therapeutic intervention has been shown to increase survival in patients with chronic obstructive pulmonary disease (COPD) and respiratory failure. Although this concept has been extended by analogy to chronic respiratory failure caused by respiratory and non-respiratory diseases, continuous oxygen therapy has not been shown to be effective in other disorders. Oxygen therapy has not been shown to improve survival in patients with COPD and moderate hypoxaemia, nor is there consensus regarding its use during nocturnal desaturations in COPD or desaturations caused by effort. The choice of the oxygen source must be made on the basis of criteria such as technical issues, patient comfort and adaptability and cost. Flow must be adjusted to achieve appropriate transcutaneous oxyhaemoglobin saturation correction.

Oxigenoterapia continua domiciliaria

Oxygen therapy is defined as the therapeutic use of oxygen and consists of administering oxygen at higher concentrations than those found in room air, with the aim of treating or preventing hypoxia. This therapeutic intervention has been shown to increase survival in patients with chronic obstructive pulmonary disease (COPD) and respiratory failure. Although this concept has been extended by analogy to chronic respiratory failure caused by respiratory and non-respiratory diseases, continuous oxygen therapy has not been shown to be effective in other disorders. Oxygen therapy has not been shown to improve survival in patients with COPD and moderate hypoxaemia, nor is there consensus regarding its use during nocturnal desaturations in COPD or desaturations caused by effort. The choice of the oxygen source must be made on the basis of criteria such as technical issues, patient comfort and adaptability and cost. Flow must be adjusted to achieve appropriate transcutaneous oxyhaemoglobin saturation correction.