Oxygen therapy in COPD and interstitial lung disease: navigating the knowns and unknowns

A Ramped Treadmill Protocol Exercise Test Identifies Higher Ambulatory Oxygen Needs in Idiopathic Pulmonary Fibrosis and Chronic Obstructive Pulmonary Disease

Rationale: In the United States, ambulatory oxygen is recommended for patients with idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) who experience symptomatic exertional hypoxemia. Ambulatory oxygen need is often determined by submaximal hall walk testing; however, this may fail to accurately characterize exertional hypoxemia in some patients. Objectives: Assess for differences in ambulatory oxygen needs between patients with IPF and COPD who completed a ramped treadmill protocol exercise test (RTPET) and correlate oxygen flow rates determined at highest-level (HL) exertion with lung function and exercise parameters. Oxygen need is defined as the flow rate needed to maintain oxygen saturation ⩾90% in patients who desaturate to ⩽88%. Methods: We conducted a retrospective review of RTPET results for patients with IPF and COPD who also recently completed spirometry. The RTPET has three phases: rest, submaximal usual pace (UP) walking at 0% treadmill grade for 3 minutes, and HL walking at the UP walk speed with increasing treadmill grade by 2% every 2 minutes. Patients with IPF were part of a clinical registry, whereas patients with COPD were identified based on diagnosis coding and spirometry (forced expiratory volume in 1 s/forced vital capacity < 0.70). The RTPET for both groups was completed based on a pulmonologist's referral. Results: We included 329 patients with IPF and 2,343 patients with COPD. A greater proportion of patients with IPF required ambulatory oxygen to maintain saturation ⩾90% at HL exertion. After adjusting for demographic covariates and exercise parameters, patients with IPF required higher ambulatory oxygen flow rates than subjects with COPD with similar diffusion capacity of carbon monoxide values. Of patients who did not require oxygen with submaximal UP testing, 49% with IPF and 24% with COPD required oxygen at HL exertion. Conclusions: The RTPET identified higher oxygen flow needs at HL exertion in patients with IPF versus patients with COPD; however, in both diseases, there was a significant proportion of patients who were only found to have exertional desaturation at HL exertion. Reliance on submaximal testing may fail to meet the needs of patients with IPF and COPD. Further studies are needed to determine if oxygen prescriptions targeting the highest level of desaturation improve clinical outcomes, symptoms, or quality of life.

Influence of home-based pulmonary rehabilitation program among people with interstitial lung disease: A pre-post study

INTRODUCTION

Access to interstitial lung disease programs may not be available in rural settings. Home-based pulmonary rehabilitation (PR) programs have been proposed as an alternative to hospital-based programs.

METHOD

Forty participants with ILD underwent a structured unsupervised home-based pulmonary rehabilitation program from September 2020 to September 2022. Quality of life was assessed using St. George Respiratory Questionnaire (SGRQ) and functional capacity using 6-minute walk test (6MWT). The outcome measures were assessed at baseline and 4 weeks post-unsupervised home-based PR program.

RESULT

We recruited 40 participants with ILD. There was statistically significant improvement in the 6-minute walk distance (353.8 m and 368 m, effect size - 0.5, p ≤ .001) and quality of life using SGRQ total score (38.6 and 42.35, effect size - 2.5, p ≤ .001) between before and after receiving home-based PR among all 40 participants with ILD.

CONCLUSION

Four weeks of home-based PR program, using minimal resources, deliver short-term improvements in functional exercise capacity and quality of life among ILD participants. Our home-based PR program resulted in a quarter percentage improvement in functional capacity, and we believe that if consistency is maintained, it will result in similar changes corresponding to the already established Minimal Clinically Important Difference (MCID) of 35 m.

The 1-min sit-to-stand test as a screening tool to assess exercise-induced oxygen desaturation in normoxemic people with interstitial lung disease

BACKGROUND

In patients with interstitial lung disease (ILD), exercise-induced desaturation during the 6-min walk test (6MWT), specifically nadir oxygen saturation (nSpO2) of ≤88 % is a negative prognostic marker. As the 6MWT is often impractical for ILD patients, the aim of this study is to compare the 1-min sit-to-stand test (1minSTS) with the 6MWT to detect exercise-induced desaturation.

METHODS

Participants were recruited from a tertiary referral clinic with both tests performed on the same day. Utilising Bland-Altman analysis, the relationship between nSpO2 on 1minSTS and 6MWT was determined. An area under the receiver operating characteristic curve (AUC) determined the ability of nSpO2 on 1minSTS test to predict SpO2 ≤88 % on 6MWT.

RESULTS

Fifty participants completed the study (idiopathic pulmonary fibrosis n = 24, 48 %; connective tissue disease associated ILD n = 20, 40 %; other ILD n = 6, 12 %). Mean (SD) FVC%pred was 73 ± 16 %, mean DLCO%pred 57 ± 16 % and resting SpO2 99 ± 1 %. The 1minSTS resulted in less exercise-induced oxygen desaturation, with a median IQR nSpO2 of 95 % (89-98) and 93 % (85-96) respectively (p < 0.001). Moderate agreement was determined between the nSpO2 on both tests, with a mean difference of 3.2 % [-14 to +3.0 %]. The 1minSTS test accurately identified participants with nSpO2 ≤88 % on 6MWT (AUC 0.96). Oxygen desaturation ≤94 % during the 1minSTS test provided 100 % sensitivity and 87 % specificity for oxygen desaturation ≤88 % at 6MWT.

CONCLUSION

This study demonstrates that exercise-induced oxygen desaturation during the 1minSTS test correlates with oxygen desaturation on 6MWT. The 1minSTS may be a practical screening tool for ILD patients who would benefit from further exercise testing.

Understanding facilitators and barriers to oxygen therapy for patients with interstitial lung disease

BACKGROUND

Interstitial lung disease (ILD) is comprised of a heterogeneous group of pulmonary diseases. Oxygen therapy is used in patients with advanced lung disease; however, there are challenges associated with initiation of oxygen therapy specific to individuals with ILD. The key objectives of this study were to create a common understanding of the facilitators and barriers to oxygen therapy for patients with ILD, and healthcare professionals (HCP) caring for patients with ILD.

METHODS

This qualitative study included 1 hour semistructured focus groups/interviews. An iterative and concurrent process was used for data collection and analysis to allow for supplementary development of themes and concepts generated. Data analysis used a three-phase approach: coding, categorising and development of themes.

RESULTS

A total of 20 patients and/or caregivers and 31 HCP took part in 34 focus groups/interviews held over 3 months (November 2022-January 2023). Facilitators to oxygen therapy were identified including support from HCP and support groups, the perseverance and self-advocacy of patients, a straightforward administrative process and vendors/private industry that expedite access to oxygen therapy. There were also several barriers to accessing oxygen therapy for patients with ILD. The themes identified include rural disparity, testing requirements and qualifying for funding and the need for ILD-specific evidence base for oxygen therapy.

CONCLUSION

Further research is needed to facilitate development of specific exertional oxygen criteria for patients with ILD, to create supports for oxygen use and monitoring and to enable providers to tailor therapy to patients. Oxygen therapy education for ILD should address the benefits and risks of oxygen therapy.

Lung toxicity induced by anti-HER2 antibody - drug conjugates for breast cancer

Human epidermal growth factor receptor 2 (HER2) serves as both a prognostic indicator and a therapeutic target for breast cancer. Therefore, anti-HER2 therapy plays a crucial role in the treatment of HER2-positive cancer. Antibody-drug conjugates (ADCs) are composed of a monoclonal antibody, a chemical linker and a payload, wherein their aim is to reduce the toxicity associated with chemotherapy drugs by utilizing specific antibodies. Among the anti-HER2 ADCs currently approved for clinical use, trastuzumab emtansine(T-DM1) and trastuzumab deruxtecan (T-Dxd) have demonstrated remarkable efficacy in treating HER2-positive breast cancer. However, it is essential to emphasize the occurrence of lung toxicity during the treatment process, which can be life-threatening. In this review, we provide an overview of the new epidemiological features associated with interstitial lung disease (ILD) related to anti-HER2 ADCs in breast cancer. We also summarize the potential pathogenesis and explore the diagnosis and treatment strategies within this field.

Illness Perceptions, Cognitions, and Beliefs on COPD Patients' Adherence to Treatment - A Systematic Review

Background

Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory lung disease characterized by persistent respiratory symptoms and airflow limitation. Besides its irreversibility, COPD is a treatable condition, and patients would strongly benefit from being adherent to their treatments. However, almost half of them are non-adherent, and, according to several recent studies, the way the patient perceives the disease might influence this variable.

Aim

This systematic review provided a synthesis of studies about the relationships between illness perceptions (IP), cognitions, beliefs, and adherence in COPD.

Methods

English language publications were searched in PubMed, Medline, Scopus, ResearchGate, PsycINFO, and Cochrane Library databases from November 2022 to February 2023, following PRISMA guidelines. The reference lists of eligible studies were also searched. Data extraction and critical appraisal were undertaken by two reviewers working independently.

Results

A total of 14 studies were included. Adherence to treatment in COPD is confirmed to be low, using both self-report questionnaires and objective assessment systems. Most studies concluded that COPD is perceived as a moderate threat destined to last forever, even if many participants referred to little disease knowledge. This perception did not change between adherent and non-adherent groups. Those who considered more necessary to take their medicines and had a caregiver were more adherent and less concerned about their future. On the other side, forgetfulness, lack of trust in medications, and difficulties in understanding how to take them were perceived as the main causes of non-adherence. Other predictors of non-adherence, like depression, low self-efficacy, and severity of disease were confirmed.

Conclusion

The systematic review highlights the variability of the relationship between IP, cognitions and beliefs, and COPD treatment adherence. A new level of awareness of the relationship between patients' subjective point of view and treatment adherence may inform future treatment options and promote a more personalized intervention.

Progressive pulmonary fibrosis: an expert group consensus statement

This expert group consensus statement emphasises the need for standardising the definition of progressive fibrosing interstitial lung diseases (F-ILDs), with an accurate initial diagnosis being of paramount importance in ensuring appropriate initial management. Equally, case-by-case decisions on monitoring and management are essential, given the varying presentations of F-ILDs and the varying rates of progression. The value of diagnostic tests in risk stratification at presentation and, separately, the importance of a logical monitoring strategy, tailored to manage the risk of progression, are also stressed. The term "progressive pulmonary fibrosis" (PPF) exactly describes the entity that clinicians often face in practice. The importance of using antifibrotic therapy early in PPF (once initial management has failed to prevent progression) is increasingly supported by evidence. Artificial intelligence software for high-resolution computed tomography analysis, although an exciting tool for the future, awaits validation. Guidance is provided on pulmonary rehabilitation, oxygen and the use of non-invasive ventilation focused specifically on the needs of ILD patients with progressive disease. PPF should be differentiated from acute deterioration due to drug-induced lung toxicity or other forms of acute exacerbations. Referral criteria for a lung transplant are discussed and applied to patient needs in severe diseases where transplantation is not realistic, either due to access limitations or transplantation contraindications. In conclusion, expert group consensus guidance is provided on the diagnosis, treatment and monitoring of F-ILDs with specific focus on the recognition of PPF and the management of pulmonary fibrosis progressing despite initial management.

2022 Brazilian Thoracic Association recommendations for long-term home oxygen therapy

Some chronic respiratory diseases can cause hypoxemia and, in such cases, long-term home oxygen therapy (LTOT) is indicated as a treatment option primarily to improve patient quality of life and life expectancy. Home oxygen has been used for more than 70 years, and support for LTOT is based on two studies from the 1980s that demonstrated that oxygen use improves survival in patients with COPD. There is evidence that LTOT has other beneficial effects such as improved cognitive function, improved exercise capacity, and reduced hospitalizations. LTOT is indicated in other respiratory diseases that cause hypoxemia, on the basis of the same criteria as those used for COPD. There has been an increase in the use of LTOT, probably because of increased life expectancy and a higher prevalence of chronic respiratory diseases, as well as greater availability of LTOT in the health care system. The first Brazilian Thoracic Association consensus statement on LTOT was published in 2000. Twenty-two years later, we present this updated version. This document is a nonsystematic review of the literature, conducted by pulmonologists who evaluated scientific evidence and international guidelines on LTOT in the various diseases that cause hypoxemia and in specific situations (i.e., exercise, sleep, and air travel). These recommendations, produced with a view to clinical practice, contain several charts with information on indications for LTOT, oxygen sources, accessories, strategies for improved efficiency and effectiveness, and recommendations for the safe use of LTOT, as well as a LTOT prescribing model.

Multidisciplinary Care and Prognosis in Patients With COPD and Interstitial Lung Disease Prescribed Long-Term Oxygen Therapy

BACKGROUND

Home oxygen therapy is prescribed for patients with advanced lung disease based on the criteria established in landmark trials in subjects with COPD. In clinical practice, its use has been extrapolated to other diseases, including interstitial lung disease (ILD). Patients with COPD and ILD experience a high symptom burden and require access to specialized multidisciplinary care. We aimed to evaluate the health-related outcomes and supportive care needs of patients with COPD and ILD receiving home oxygen therapy.

METHODS

This was a retrospective cohort study using the oxygen database of a quaternary metropolitan teaching hospital. Patients with a diagnosis of COPD or ILD who were prescribed home oxygen therapy between January 2012-December 2018 were identified. Demographic information, results of physiologic testing, comorbidities, hospitalizations, and mortality data were collected.

RESULTS

Three hundred and eighty-four subjects were included for analysis, of whom 56% were male. The median age was 75 y. The majority (59%) had a diagnosis of COPD. Long-term oxygen therapy (LTOT) was prescribed for 187 (48.7%), with no significant demographic differences between those with COPD or ILD. Another 187 were prescribed ambulatory oxygen alone, with 55 transitioning to LTOT during the study period. Most subjects (65.4%) were referred for pulmonary rehabilitation; however, palliative care referrals were generally low (22.9%). Referrals to other medical specialties and allied health were common (82%). Transplant-free survival after commencement of LTOT was poor, with 38% of subjects surviving at 5 y. The 5-y survival of subjects with ILD after commencing on LTOT was 10% compared to 52% for those with COPD. Multivariable Cox regression analyses showed that the only predictor of survival after commencing LTOT was the principal respiratory diagnosis.

CONCLUSIONS

This study found that subjects prescribed LTOT had poor transplant-free survival after initiation, which was significantly worse for those with ILD compared to those with COPD. Despite their poor overall survival, worse than many cancers, only a minority were referred for palliative care input. Referrals to pulmonary rehabilitation were also suboptimal. This patient population had complex care needs requiring multidisciplinary management. Appropriate and early referrals to palliative care and improved care coordination for this complex group of patients are key areas for improvement in clinical practice.

Management of musculoskeletal pain in patients with idiopathic pulmonary fibrosis: a review

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic, and fatal interstitial lung disease (ILD) of unknown etiology that primarily affects the elderly. Patients with IPF suffer from a heavy symptom burden and usually have a poor quality of life. Dyspnea and dry cough are predominant symptoms of IPF. Although pain is not considered one of the main symptoms of IPF, it can occur for a variety of reasons, such as hypoxia, coughing, muscle and nerve damage, deconditioning, and steroid use. The prevalence of pain in IPF patients varies greatly, ranging from around 30 to 80%, with the prevalence being estimated mostly among patients in the end-of-life period. It manifests itself in the form of muscle pain, joint discomfort, or back and chest pain. Approaches to the treatment of chronic musculoskeletal pain in patients with IPF include pharmacological and non-pharmacological measures that are also important to optimize the treatment of other symptoms (dyspnea and cough) and the optimal treatment of comorbidities. Given the scarcity of data on this symptom in the literature, this article summarizes what is currently known about the etiology and treatment of musculoskeletal pain in IPF.

Evaluation of respiratory rate monitoring performance using a home oxygen monitoring device among patients with interstitial lung disease and chronic obstructive pulmonary disease

Background

Home monitoring devices have been developed to measure adherence to home oxygen therapy. In this study, we evaluated the performance of TeleOx^®, a commercially available remote monitoring device, in comparison with polysomnography (PSG) in patients with interstitial lung disease (ILD) and chronic obstructive pulmonary disease (COPD) and the factors that affected TeleOx^® correct use.

Methods

TeleOx^® was connected on the patient or concentrator side. The oxygen flow rates were set at 1, 3, and 5 L/min. Intraclass correlation coefficient (ICC) (2,1) was used to determine the agreement between respiratory rate measured using TeleOx^® and that measured using PSG, and the minimum acceptable level of reliability was >0.7.

Results

In total, 22 patients (16 with ILD and 6 with COPD) were assessed. In patients with ILD, the detection rate of patients' respiration assessed using TeleOx^® did not change according to the device's position. It increased from 53.5% to 79.0% by changing the position from the concentrator to the patient side in patients with COPD. The ICC (2,1) value indicated that TeleOx^® had acceptable reliability at oxygen flow rates of 1 and 3 L/min regardless of the device's position in patients with ILD (the concentrator side: 0.9 and 0.82, respectively; the patient side: 0.95 and 0.82, respectively), whereas that did only at the oxygen flow rate of 1 L/min and in connecting TeleOx^® on the patient side in patients with COPD (0.73).

Conclusion

The monitoring performance of TeleOx^® differed according to its position, oxygen flow rates, and patients' diseases.

Effects of Supplemental Oxygen on Cardiovascular and Respiratory Interactions by Extended Partial Directed Coherence in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and restrictive disease characterized by fibrosis and inflammatory changes in lung tissue producing a reduction in diffusion capacity and leading to exertional chronic arterial hypoxemia and dyspnea. Furthermore, clinically, supplemental oxygen (SupplO₂) has been prescribed to IPF patients to improve symptoms. However, the evidence about the benefits or disadvantages of oxygen supplementation is not conclusive. In addition, the impact of SupplO₂ on the autonomic nervous system (ANS) regulation in respiratory diseases needs to be evaluated. In this study the interactions between cardiovascular and respiratory systems in IPF patients, during ambient air (AA) and SupplO₂ breathing, are compared to those from a matched healthy group. Interactions were estimated by time series of successive beat-to-beat intervals (BBI), respiratory amplitude (RESP) at BBI onset, arterial systolic (SYS) and diastolic (DIA) blood pressures. The paper explores the Granger causality (GC) between systems in the frequency domain by the extended partial directed coherence (ePDC), considering instantaneous effects. Also, traditional linear and nonlinear markers as power in low (LF) and high frequency (HF) bands, symbolic dynamic indices as well as arterial baroreflex, were calculated. The results showed that for IPF during AA phase: 1) mean BBI and power of BBI-HF band, as well as mean respiratory frequency were significantly lower (p < 0.05) and higher (p < 0.001), respectively, indicating a strong sympathetic influence, and 2) the RESP → SYS interaction was characterized by Mayer waves and diminished RESP → BBI, i.e., decreased respiratory sinus arrhythmia. In contrast, during short-term SupplO₂ phase: 1) oxygen might produce a negative influence on the systolic blood pressure variability, 2) the arterial baroreflex reduced significantly (p < 0.01) and 3) reduction of RSA reflected by RESP → BBI with simultaneous increase of Traube-Hering waves in RESP → SYS (p < 0.001), reflected increased sympathetic modulation to the vessels. The results gathered in this study may be helpful in the management of the administration of SupplO₂.

Characteristics of COVID-19 Pneumonia Survivors With Resting Normoxemia and Exercise-Induced Desaturation

BACKGROUND

Survivors of coronavirus disease 2019 (COVID-19) associated pneumonia may show exercise-induced desaturation. We wondered whether these individuals show physiologic and symptom characteristics similar to individuals with chronic respiratory diseases with exercise-induced desaturation, namely COPD or interstitial lung diseases (ILD). We evaluated lung function, exercise capacity, and symptoms in these individuals compared with individuals with COPD or ILD and exercise-induced desaturation.

METHODS

Survivors of COVID-19 associated pneumonia (study individuals), normoxemic at rest with exercise-induced desaturation, underwent assessment of dyspnea, dynamic lung volumes, carbon monoxide diffusion capacity, and the 6-min walk test. Data of individuals with COPD or with ILD and exercise-induced desaturation were also retrospectively analyzed.

RESULTS

FVC was lower in individuals with COVID-19 or ILD than in those with COPD. Individuals who had COVID-19 walked < 70% of predicted and, as a whole, had a 6-min walk test performance similar to individuals with ILD but walked significantly less, showed more severe leg fatigue and dyspnea during exercise, and more exercise-induced desaturation than individuals with COPD.

CONCLUSIONS

Survivors of COVID-19 associated pneumonia, who were normoxemic at rest with exercise-induced desaturation, had alterations in lung function, exercise capacity, and symptoms similar to individuals with ILD but more severe than individuals with COPD and exercise-induced desaturation.

Acute effect of oxygen therapy on exercise tolerance and dyspnea perception in ILD patients

Ambulatory oxygen therapy (AOT) is commonly prescribed in Interstitial Lung Disease (ILD) patients, with the aim of reducing dyspnea and increasing exercise tolerance. Despite its frequent use and a reasonable physiological rationale, there is a lack of evidence supporting the effect of AOT on improving dyspnea during exercise. Moreover, dyspnea encompasses distinct sensory (intensity, quality) and affective (anxiety, fear) components with different underlying neurophysiological mechanisms. The aim of this study was to evaluate the effect of oxygen supplementation on exercise tolerance and dyspnea in ILD patients with exercise induced hypoxia (EIH). Forty-seven ILD patients performed a six minute walk test (6MWT) on room air (RA) and with oxygen supplementation (Ox). The 6MWT distance (6MWD) was significantly greater with oxygen supplementation (RA: 242±143 m vs Ox: 345±106 m p<0,01). With oxygen supplementation, the overall dyspnea and anxiety significantly decreased both at rest (1,1±1,4 Borg Unit (BU) vs 0,4±0,9BU , p.<0.01, and 1,1±1,6BU vs 0,5±1,3 BU, p.<0.05, respectively) and at the end of exercise (5,1±2,6 BU vs 3,7±2,5 BU, p.<0.001 and 3,4 ±2,9 vs 2,5 ±2,8, p.<0.01, respectively) despite a greater walked distance. In ILD patients with EIH, oxygen supplementation increases the exercise tolerance and reduces overall dyspnea perception and the anxiety component of breathlessness.

Management of Connective Tissue Disease-Associated Interstitial Lung Disease

The presence of interstitial lung disease (ILD) negatively affects prognosis among patients with an underlying connective tissue disease (CTD). The initial approach to care should determine whether the CTD-ILD needs pharmacologic treatment or not. There is little direct evidence to guide who and how to treat. At present, any severe, active, and/or progressive ILD should be pharmacologically treated. Immunosuppressants and/or corticosteroids are the mainstay of pharmacologic therapy for all CTD-ILDs, whereas antifibrotics may be beneficial in some scenarios. A comprehensive and multidisciplinary approach to management is also an important aspect of patient care.

Differences in cerebral oxygenation during exercise in patients with idiopathic pulmonary fibrosis with and without exertional hypoxemia: does exercise intensity matter?

INTRODUCTION AND OBJECTIVES

Patients with idiopathic pulmonary fibrosis (IPF) present respiratory derangements at rest and during exercise, accompanied by exercise intolerance. Some patients may develop profound exertional desaturation even without resting hypoxemia. Evidence suggests the involvement of reduced cerebral-oxygenation in exercise intolerance. We aimed to examine (i) differences in cerebral-oxygenation during exercise between IPF patients with and without isolated exertional desaturation, (ii) whether the impairments in cerebral-oxygenation are detected at similar exercise intensity, and (iii) correlations between cerebral-oxygenation indices, disease severity, and 6-min walk test (6MWT).

MATERIALS AND METHODS

Patients with IPF (n = 24; 62.1 ± 9.3 years) without resting hypoxemia underwent cardiopulmonary exercise testing (CPET) with cerebral-oxygenation monitoring via near-infrared-spectroscopy (NIRS). Βased on their pulse-oxymetry saturation (SpO₂) during CPET, patients were divided into the "exertional-desaturators" group (SpO_2nadir≤89% and ≥6% drop in SpO₂) and the "non-exertional-desaturators" group (SpO_2nadir≥90% and ≤5% drop).

RESULTS

During CPET, the "exertional-desaturators" group exhibited lower oxygenated-hemoglobin (-0.67 ± 1.48 vs. 0.69 ± 1.75 μmol/l; p < 0.05) and higher deoxygenated-hemoglobin (1.67 ± 1.13 vs. 0.17 ± 0.62 μmol/l; p < 0.001) than the "non-exertional-desaturators" group. A different pattern (p < 0.01) in cerebral-oxygenation responses was observed in the two groups. In exertional-desaturators oxygenated-hemoglobin declined below baseline even at low/moderate-intensity exercise (p < 0.05), whereas, in non-exertional-desaturators cerebral-oxygenation declined (p < 0.05) at high-intensity exercise. Cerebral-NIRS indices correlated (p < 0.05) with CPET-duration, dyspnea, diffusion capacity, and 6MWT.

CONCLUSIONS

During incremental exercise, patients with IPF and exertional desaturation present a significant decline in cerebral-oxygenation even during low-intensity exercise. Our findings support the implementation of longer-duration rehabilitation programs in IPF so that lower intensity exercise can be applied at the initial stages. (NCT03683082).

Nocturnal hypoxaemia in interstitial lung disease: a systematic review

BACKGROUND

Patients with interstitial lung disease (ILD) are at risk of developing nocturnal hypoxaemia due to ventilatory restriction and impaired gas exchange that worsen with supine posture and reduced ventilatory drive during sleep. This systematic review synthesised literature on the diagnostic evaluation, epidemiology, associations, management and prognosis of nocturnal hypoxaemia in ILD.

METHODS

Ovid MEDLINE, Embase and CENTRAL databases were searched for eligible studies. Meta-analyses with subgroup analyses were conducted, where possible.

RESULTS

Fifty-three studies were included (total participant number=2590). The most common definition for clinically significant nocturnal hypoxaemia was ≥10% of total sleep time with oxyhaemoglobin saturation <90%, with pooled prevalence of 37%. There were no significant differences in pooled prevalence according to ILD subtype and comorbid obstructive sleep apnoea status. Study heterogeneity precluded meta-analysis of associations and prognosis. Diffusing capacity for carbon monoxide (DLCO) and echocardiographic features for pulmonary hypertension were consistently associated with nocturnal hypoxaemia. There were inconsistent associations between nocturnal hypoxaemia with ILD subtype and severity. Multivariable analyses in most studies demonstrated significant associations of nocturnal hypoxaemia with survival. Two small short-term intervention studies demonstrated that supplemental oxygen of 1-3 L/min corrected nocturnal hypoxaemia, with improved heart rate control during in-laboratory observation and increased serum antioxidant levels after 1 month of therapy.

CONCLUSION

Nocturnal hypoxaemia is common, associated with DLCO impairment and markers suggestive of pulmonary hypertension, and a potential prognostic factor in patients in ILD. There is a need to establish a consensus definition of nocturnal hypoxaemia and evaluate long-term effects of nocturnal supplemental oxygen in ILD.

Portable Oxygen Therapy: Is the 6-Minute Walking Test Overestimating the Actual Oxygen Needs?

The appropriate titration for the personalized oxygen needs of patients with chronic obstructive pulmonary disease (COPD) and severe hypoxemia is a determining factor in the success of long-term oxygen therapy. There are no standardized procedures to assist in determining the patient’s needs during the physical activities of daily life. Despite that effort tests are a wide broad approach, further research concerning the development of protocols to titrate O₂ therapy is needed. The main objective of this study was to assess whether the level of oxygen titrated through the 6-minute walking test (6MWT) for patients with COPD and exertional hypoxemia is adequate to meet the patients’ demand during their activities of daily living. Physiological and subjective variables were estimated for a study population during two walking tests: a 6MWT and a 20-minute walking circuit (20MWC), designed ad-hoc to reproduce daily physical activities more truthfully. The results indicate that in a significant proportion of patients, the 6MWT might not accurately predict their oxygen needs at a domiciliary environment. Therefore, the titration of the portable O₂ therapy could not be optimal in these cases, with the detrimental impact on the patient’s health (hyperoxia episodes), the autonomy of the oxygen device, and the decrease of time out of the home.

Oxygen for interstitial lung diseases

PURPOSE OF REVIEW

Supplemental oxygen therapy is prescribed for management of hypoxaemia in patients with interstitial lung disease (ILD). This review summarizes current evidence and implications of the use of supplemental oxygen therapy at home and during exercise training in ILD.

RECENT FINDINGS

Despite the significance of hypoxaemia in patients with ILD, there is a lack of high-quality evidence to guide the use of oxygen therapy in this population. Recent studies suggest that ambulatory oxygen may improve symptoms and health-related quality of life in patients with ILD. Long-term oxygen therapy for resting hypoxaemia in ILD is recommended by international guidelines. Supplemental oxygen during exercise may augment training effects, whereas therapeutic effects of nocturnal oxygen therapy are yet to be evaluated in patients with ILD. Nevertheless, it is important to consider the potential burden imposed by oxygen therapy on patients' daily activities of living.

SUMMARY

Ambulatory oxygen may be considered in ILD patients with exertional hypoxaemia, with long-term oxygen therapy being a standard care for resting hypoxaemia. Trials are currently underway to clarify therapeutic potentials of supplemental oxygen for exertional hypoxaemia and during exercise training in ILD patients, with additional research needed for the evaluation of nocturnal oxygen therapy.

Hemodynamic response to low-flow acute supplemental oxygen in idiopathic pulmonary fibrosis and elderly healthy subjects

BACKGROUND

Hemodynamic response to supplemental oxygen in idiopathic pulmonary fibrosis (IPF) is still not well known.

OBJECTIVE

To determine and compare the effect of low-flow acute supplemental oxygen on the hemodynamics of IPF patients and matched healthy subjects.

METHODS

Descriptive and comparative study in 20 IPF-patients and 19 Control-subjects, (60-80 years old) breathing ambient air followed by acute nasal low-flow (3 L/min) supplemental oxygen. Non-invasive methods were used during the supine position to evaluate oxygen saturation, heart rate, stroke volume index, cardiac output index, total peripheral resistance and arterial blood pressure.

RESULTS

Breathing ambient air, IPF (vs. Control) presented lower values in stroke volume index (38.7 [29.4-43.2] vs. 45.4 [38.4-50.9] mL•kg-1•m²; p=0.009) and cardiac output index (2.484 [2.268 - 2.946] vs. 2.857 [2.628 - 3.054] L•min^-1•m^-2; p=0.028), with higher total peripheral resistance (1644 [1559-2076] vs. 1505 [1366-1784] dyne•s•cm^-5; p=0.017). During supplemental oxygen (vs. ambient air), both groups increased oxygen saturation above 94% (p<0.001) while heart rate decreased about 6 to 8% (p<0.001); stroke volume index increased around 7% in the Control-group (p=0.004) but only 1% in the IPF-group (p=0.017). In addition, IPF showed increments in total peripheral resistance (1644 [1559-2076] vs. 1706 [1554-2278] dyne•s•cm^-5; p=0.017) with subsequent decrements in cardiac output index (2.484 [2.268 - 2.946] vs. 2.362 [2.139 - 2.664] L•min^-1•m^-2; p<0.001).

CONCLUSION

Low-flow acute supplemental oxygen in IPF causes a meaningful decrement in cardiac output due to greater reduction in heart rate and increment in total peripheral resistance than matched healthy subjects. Knowing the hemodynamic profile of IPF patients may be helpful in determining their management with supplemental oxygen.

Outcome of Lung Transplantation as a Treatment of Patients With Chronic Obstructive Pulmonary Disease: A Single-Center Study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide. Lung transplantation (LTx) is often the only therapeutic option for patients with end-stage COPD. The aim of the study was to establish whether patients with end-stage COPD benefited from lung transplantation and assess the pulmonary function by the 6-Minute Walk Test (6MWT) and forced expiratory volume in 1 second (FEV1).

METHODS

A retrospective study was carried out in the group of 69 patients (40 recipients, 18 patients currently waiting, and 11 patients who died while waiting for a lung graft) diagnosed with end-stage COPD, referred to the Silesian Center for Heart Diseases' Lung Transplant Ward, and qualified to be treated by means of lung transplantation between 2006 and 2018. The beginning of the observation for all 69 patients was a qualification date.

RESULTS

Kaplan-Meier estimation determined that graft recipients noted 50% probability of survival at approximately 5.5 years, whereas patients from the other group had such parameters at about 1.4 years. The average results FEV1 obtained at qualification were 23.69% for single lung transplantation (SLT); and 22.06% for double lung transplantation (DLT). Average patient acquired 158.07m in the 6MWT. One year after procedure the average values of FEV1 were SLT, 55.83%; DLT, 79.54%; and 430.7 m in the 6MWT overall.

CONCLUSIONS

Qualified patients who underwent lung transplantation lived longer than those who did not undergo such a procedure. We observed a difference in SLT and DLT recipients.