Thoracic Society of Australia and New Zealand clinical practice guideline on adult home oxygen therapy

This Thoracic Society of Australia and New Zealand Guideline on the provision of home oxygen therapy in adults updates a previous Guideline from 2015. The Guideline is based upon a systematic review and meta-analysis of literature to September 2022 and the strength of recommendations is based on GRADE methodology. Long-term oxygen therapy (LTOT) is recommended for its mortality benefit for patients with COPD and other chronic respiratory diseases who have consistent evidence of significant hypoxaemia at rest (PaO2 ≤ 55 mm Hg or PaO2 ≤59 mm Hg in the presence of hypoxaemic sequalae) while in a stable state. Evidence does not support the use of LTOT for patients with COPD who have moderate hypoxaemia or isolated nocturnal hypoxaemia. In the absence of hypoxaemia, there is no evidence that oxygen provides greater palliation of breathlessness than air. Evidence does not support the use of supplemental oxygen therapy during pulmonary rehabilitation in those with COPD and exertional desaturation but normal resting arterial blood gases. Both positive and negative effects of LTOT have been described, including on quality of life. Education about how and when to use oxygen therapy in order to maximize its benefits, including the use of different delivery devices, expectations and limitations of therapy and information about hazards and risks associated with its use are key when embarking upon this treatment.

How to take arms against central apneas in heart failure

Introduction Despite being a risk mediator in several observational studies, central apneas are currently orphan of treatment in heart failure. After the neutral effects on survival of two randomized controlled trials (RCTs) based on the use of positive airway pressure (the CANPAP and SERVE-HF trials), two alternative hypotheses have been formulated: 1) Periodic breathing/Cheyne-Stokes respiration (PB/CSR) in HF is protective. Indeed, the Naughton's hypothesis assumes that hyperventilation leads to increased cardiac output, lung volume, oxygen storage and reduced muscle sympathetic nerve activity, while central apnea to respiratory muscle rest and hypoxia-induced erythropoiesis. 2) The use of positive airway pressure is just a wrong treatment for PB/CSR. If this is the case, the search for novel potential alternative treatment approaches is mandatory in HF. Areas covered This review will focus on the crucial issue of whether PB/CSR should be treated or not in HF, first by outlining the ideal design of pathophysiological studies to test the Naughton's hypothesis and second by summarizing the treatment strategies so far proposed for PB/CSR in HF and identifying the most promising options to be tested in future RCTs. Expert commentary It is likely that PB/CSR may be compensatory in some cases, but after a certain threshold (to be defined) it becomes maladaptive with negative prognostic meaning in HF. The development of a pathophysiologically based treatment targeting feedback resetting and neurohormonal activation underlying PB/CSR is likely to be the best option to obtain survival benefits in HF.

Management of Sleep Apnea Syndromes in Heart Failure

Central sleep apnea (CSA) and obstructive sleep apnea (OSA) are prevalent in heart failure (HF) and associated with a worse prognosis. Nocturnal oxygen therapy may decrease CSA events, sympathetic tone, and improve left ventricular ejection fraction, although mortality benefit is unknown. Although treatment of OSA in patients with HF is recommended, therapy for CSA remains controversial. Continuous positive airway pressure use in HF-CSA may improve respiratory events, hemodynamics, and exercise capacity, but not mortality. Adaptive servo ventilation is contraindicated in patients with symptomatic HF with predominant central sleep-disordered events. The role of phrenic nerve stimulation in CSA therapy is promising.

Linkage of sleep-disordered breathing and acute aortic dissection with patent false lumen

Sleep-disordered breathing (SDB) is known as a cardiovascular risk factor and has high prevalence in hypertension, which is a major risk factor of aortic dissection (AD). However, the impact of SDB on AD has not been fully clarified. The aim of this study is to elucidate the impact of SDB on AD, especially on the type of false lumen in AD. We enrolled twenty-three consecutive patients with acute AD (mean age: 66 ± 13 years). All subjects were evaluated by an ambulatory polygraphic sleep monitoring within 1 month from the onset. AD was evaluated by axial images of computed tomography. We comparatively analyzed SDB and AD. 35 % of the subjects presented severe OSA (apnea-hypopnea index: AHI ≥30). The patent false lumen group showed significantly higher systolic and diastolic blood pressure (BP) on arrival and AHI, and lower percutaneous oxygen saturation (SaO2) compared with those in the thrombosed false lumen group. The prevalence of severe SDB was higher in the patent false lumen group (60 vs 15 %, p = 0.039). Systolic BP on arrival was significantly correlated with AHI (r = 0.457, p = 0.033) and the minimum SaO2 (r = -0.537, p = 0.010). The present study revealed close linkage between SDB and AD, and a high prevalence of SDB among AD patients. Severe SDB was related to the development of AD, especially for the patent false lumen type through highly elevated BP which might be easily evoked in the presence of severe SDB. Repetitive occurrence of intrathoracic negative pressure also might influence the repair or closure of false lumen of AD, although the present analysis did not reach statistical significance.

End-of-life care in patients with heart failure

Stage D heart failure (HF) is associated with poor prognosis, yet little consensus exists on the care of patients with HF approaching the end of life. Treatment options for end-stage HF range from continuation of guideline-directed medical therapy to device interventions and cardiac transplantation. However, patients approaching the end of life may elect to forego therapies or procedures perceived as burdensome, or to deactivate devices that were implanted earlier in the disease course. Although discussing end-of-life issues such as advance directives, palliative care, or hospice can be difficult, such conversations are critical to understanding patient and family expectations and to developing mutually agreed-on goals of care. Because patients with HF are at risk for rapid clinical deterioration or sudden cardiac death, end-of-life issues should be discussed early in the course of management. As patients progress to advanced HF, the need for such discussions increases, especially among patients who have declined, failed, or been deemed to be ineligible for advanced HF therapies. Communication to define goals of care for the individual patient and then to design therapy concordant with these goals is fundamental to patient-centered care. The objectives of this white paper are to highlight key end-of-life considerations in patients with HF, to provide direction for clinicians on strategies for addressing end-of-life issues and providing optimal patient care, and to draw attention to the need for more research focusing on end-of-life care for the HF population.

Questionnaire survey on the continuity of home oxygen therapy after a disaster with power outages

BACKGROUND

After the Great East Japan Earthquake, oxygen-dependent patients in areas experiencing power outages could not continue home oxygen therapy (HOT) without oxygen cylinders. The purpose of this study was to examine use of oxygen cylinders in areas experiencing power outages and the effects of HOT interruption on patients' health.

METHODS

Questionnaires were mailed to 1106 oxygen-dependent patients and HOT-prescribing physicians in Akita, near the disaster-stricken area. We investigated patients' actions when unable to use an oxygen concentrator and classified the patients based on oxygen cylinder use. Patients who experienced an interruption of or reduction in oxygen flow rate by their own judgment were assigned to the "interruption" and "reduction" groups, respectively; those who maintained their usual flow rate were assigned to the "continuation" group. Differences were tested using analysis of variance and the χ2 tests.

RESULTS

In total, 599 patients responded to the questionnaire. Oxygen cylinders were supplied to 574 patients (95.8%) before their oxygen cylinders were depleted. Comparison of the continuation (n=356), reduction (n=64), and interruption (n=154) groups showed significant differences in family structure (p=0.004), underlying disease (p=0.014), oxygen flow rate (p<0.001), situation regarding use (p<0.001), knowledge of HOT (p<0.001), and anxiety about oxygen supply (p<0.001). There were no differences in changes in physical condition.

CONCLUSIONS

Most patients could receive oxygen cylinders after the disaster. Some patients discontinued their usual oxygen therapy, but their overall health status was not affected.

Links between sleep disordered breathing, coronary atherosclerotic burden, and cardiac biomarkers in patients with stable coronary artery disease

BACKGROUND

Sleep disordered breathing (SDB) is highly prevalent in patients with cardiovascular disease, although it is not clear whether SDB has any link to coronary atherosclerotic burden in patients with stable coronary artery disease (CAD). This study sought to analyze the links between SDB, coronary atherosclerotic burden, and cardiac biomarkers in stable CAD patients.

METHODS AND RESULTS

We studied 83 consecutive patients who underwent coronary angiography or scheduled percutaneous coronary intervention. SDB was evaluated by an ambulatory polysomnographic monitoring device. Coronary atherosclerotic burden was evaluated by the Gensini score, and myocardial stress/injury were assessed by measuring plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high sensitivity troponin T (hs-TnT). Patients with an apnea hypopnea index (AHI)≧15 events/h (n=32) showed significantly higher Gensini score (35.7±38.0 vs 20.1±19.7, p=0.033) than those with AHI<15. The higher AHI group showed significantly higher NT-proBNP (275.8±402.6 pg/ml vs 131.9±146.3 pg/ml, p=0.047) and hs-TnT levels (0.011±0.005 ng/ml vs 0.008±0.003 ng/ml, p=0.015). Furthermore it was revealed that AHI significantly correlated with the Gensini score (r=0.253, p=0.036), NT-proBNP (r=0.266, p=0.027), and hs-TnT (r=0.274, p=0.023), and multiple stepwise linear regression analysis revealed that AHI (β=0.257, p=0.029) and history of smoking (β=0.244, p=0.038) were independently correlated with Gensini score among clinical and SDB-related parameters.

CONCLUSIONS

Severity of SDB has a significant link to the severity of coronary atherosclerotic burden, which also reflected elevated NT-proBNP and hs-TnT as silent myocardial ischemia and minute myocardial injury even in stable CAD patients.

Effectiveness of a portable device and the need for treatment of mild-to-moderate obstructive sleep-disordered breathing in patients with cardiovascular disease

BACKGROUND AND PURPOSE

In Japan, there are two sleep-disordered breathing (SDB)-related problems, which include diagnosing SDB using a portable device (PD) and treating mild-to-moderate SDB (mm-SDB) using continuous positive airway pressure (CPAP) for severe SDB (s-SDB) in obstructive sleep apnea (OSA) patients. Our aims were to evaluate the effectiveness of a PD in diagnosing SDB in patients with cardiovascular disease (CVD), and to assess the difference between mm-SDB [apnea-hypopnea index (AHI): 20-40h(-1)] and s-SDB (AHI: >40h(-1)) using brain natriuretic peptide (BNP) in OSA patients.

METHODS AND SUBJECTS

After their underlying CVD was treated, full-night sleep studies using polysomnography (PSG) and PD were performed on the same day.

RESULTS

Eighty-three patients underwent full-night PSG simultaneously with PD. The average duration of the sleep study was 8.6+/-6.2 days. There was a tendency for a higher AHI value obtained with PSG (PSG, 28.9+/-24.3h(-1); PD, 22.3+/-16.7h(-1); p=0.05). However, the specificity and sensitivity of diagnosing SDB using PD were 86% and 81%, respectively. Using PD, twenty-nine OSA patients had mm-SDB and eleven patients had s-SDB. The BNP value was higher in the mm-SDB patients (318+/-550pg/ml) than in the s-SDB patients (202+/-160pg/ml).

CONCLUSIONS

The PD was effective in diagnosing SDB in patients with CVD. The BNP value was higher in the mm-SDB patients. Therefore, they need to be treated with CPAP to treat underlying CVD.

Valve repair improves central sleep apnea in heart failure patients with valvular heart diseases

BACKGROUND

Recent studies suggest that treatment of heart failure (HF) could improve cardiac function and sleep apnea syndrome (SAS), but it is unknown how cardiac surgery may affect SAS in HF patients. Relationships between HF with valvular heart diseases and 2 types of SAS (obstructive sleep apnea (OSA) and central sleep apnea (CSA)) were examined. The effects of valve repair surgery on OSA and CSA was also investigated.

METHODS AND RESULTS

Polysomnography, echocardiography and right cardiac catheterization were used to study 150 severe HF patients with mitral valvular and/or aortic valvular diseases. Significant associations between SAS and age, gender, body mass index, or hypertension were observed. The value of the CSA-apnea index (AI) was significantly correlated with pulmonary capillary wedge pressure (PCWP) and mean pulmonary artery pressure (PAP). These associations were not identified for OSA-AI. Valve repair surgery was used to treat 74 patients with severe SAS. The treatment led to a significant improvement in PCWP and mean PAP, and CSA-AI, but not in OSA-AI.

CONCLUSIONS

These findings suggest close associations between CSA and cardiac function in HF patients with valvular heart diseases. Furthermore, improvement of cardiac function with valvular surgery reduces the severity of CSA in HF patients with valvular heart diseases.

[Management of central sleep apnea]

Central sleep apnea is highly prevalent in association with heart failure, some neurological diseases and chronic opioids use. There are two main categories of central sleep apnea respectively related with different underlying conditions. Some hypocapnic patients exhibit respiratory control system instability and central apnea occurs when PaCO(2) falls below the threshold for apnea during sleep. The other group are patients with chronic hypercapnia mainly in the context of neuromuscular disorders or obesity hypoventilation syndrome. All these patients should be assessed by recording blood gases, polysomnography and ventilatory responses to CO(2). Cardiologic assessment should include pro-brain natriuretic factor (pro-BNP) and cardiac echography whereas neurological examination requires brain imaging and/or electromyography. Ventilatory supports used for treating central sleep apnea are non-invasive ventilation and servo-assisted ventilation in hypercapnic and hypocapnic patients respectively.

Obstructive sleep apnea and cardiovascular disease

Over the past few decades, sleep apnea has emerged as an important potential etiologic factor in a broad range of cardiac and vascular diseases. These disease conditions include hypertension, coronary artery disease, myocardial infarction, heart failure, and stroke. Recognition of the role of sleep apnea in clinical cardiology is also increasing in Japan. Although sleep apnea has been strongly linked to obesity in Western populations, in Japanese and other Asian populations there is evidence to indicate that sleep apnea may be prevalent even at lower levels of obesity. In this review we address the epidemiology of sleep apnea. Since sleep apnea includes the combined stresses of hypoxemia, apnea, and disrupted sleep, we also review briefly the potential disease mechanisms that may be activated as a consequence of sleep apnea. We further examine the role of sleep apnea in the pathophysiology and management of specific cardiovascular conditions. Overall, while the evidence of sleep apnea as a causal mechanism in cardiovascular disease is strong and increasing, definitive evidence of the etiologic role of sleep apnea has yet to be obtained. The evidence is most clear in patients with hypertension. Also remaining to be established is whether the treatment of sleep apnea prevents cardiac and vascular events. With regard to this question, although the available data strongly suggest that continuous positive airway pressure treatment is beneficial, randomized control trials are needed in order to confirm this.

Improvement of quality of life with nocturnal oxygen therapy in heart failure patients with central sleep apnea

BACKGROUND

Previously, we reported the benefit of 12 weeks of home oxygen therapy (HOT) in patients with central sleep apnea (CSA) and heart failure (HF). In the present study, we attempted to confirm the sustained efficacy of HOT in the long term treatment.

METHODS AND RESULTS

In the present study, 51 patients with CSA and HF (New York Heart Association (NYHA) functional classes II-III) were assigned to receive either nocturnal oxygen (HOT group n=26) or usual breathing (control group n=25) for 52 weeks. In the HOT group, greater reduction in apnea and hypopnea and greater increase in nocturnal oxygen saturation were observed. These changes were associated with greater improvement in the Specific Activity Scale (0.82 +/-1.17 vs -0.11 +/-0.73 Mets, P=0.009) in NYHA functional class (P=0.007) and in ejection fraction (5.45 +/-11.94 vs 1.28 +/-9.77%). There were no significant differences in the cardiac event rates; however, the later divergence favored the HOT group.

CONCLUSIONS

The 52-week HOT was well tolerated and the benefit observed in the 12-week trial was sustained over a prolonged period of time. HOT was considered to be a valuable non-pharmacological therapeutic addition for HF patients with CSA.

Sleep-disordered breathing in patients with decompensated heart failure

Sleep-disordered breathing (SDB) has a higher prevalence in patients with heart failure than in the general middle-aged population. Obstructive sleep apnea (OSA), one of the forms of SBD, promotes poorly controlled hypertension, coronary events, and atrial fibrillation events that can lead to acutely decompensated heart failure (ADHF), and evidence suggests that untreated OSA increases mortality in patients with heart failure. Cheyne-Stokes respiration and central sleep apnea (CSA) have long been associated with heart failure and, in many patients, can coexist with OSA. In this article, we propose a systematic approach to diagnose and treat OSA in patients with ADHF based on current evidence.