Short burst oxygen therapy after activities of daily living in the home in chronic obstructive pulmonary disease

Home Oxygen in Chronic Obstructive Pulmonary Disease

Two landmark trials conducted more than 35 years ago provided scientific evidence that, under very specific circumstances, long-term oxygen therapy (LTOT) may prolong life. These two trials enrolled 290 patients with chronic obstructive pulmonary disease and severe daytime hypoxemia documented by direct arterial blood gas measurement. From that time, LTOT became a standard of care, and the indications for oxygen therapy expanded to include nocturnal oxygen therapy for isolated nocturnal oxygen desaturation, ambulatory oxygen to correct exercise-induced desaturation, and short-burst oxygen to relieve dyspnea. In most cases, the rationale for broadening the indications for oxygen therapy is that, if hypoxemia exists, correcting it by increasing the Fi_O2 should help. However, with the exception of LTOT in severely hypoxemic patients with chronic obstructive pulmonary disease, randomized controlled trials of oxygen therapy have failed to demonstrate clinically significant benefits. Also, adherence to LTOT is usually suboptimal. Important areas for future research include improving understanding of the mechanisms of action of supplemental oxygen, the clinical and biochemical predictors of responsiveness to LTOT, the methods for measuring and enhancing adherence to LTOT, and the cost-effectiveness of oxygen therapy. A standardization of terminology to describe the use of supplemental oxygen at home is provided.

Home oxygen therapy: evidence versus reality

INTRODUCTION

LTOT is a well-established treatment option for hypoxemic patients. Scientific evidence for its benefits of LTOT dates back to the 1980s, when two randomized controlled trials showed prolonged survival in COPD-patients undergoing LTOT for at least 15 hours/day. In contrast, the potential benefits of LTOT in non-COPD-patients has not been well researched and the recommendations for its application are primarily extrapolated from trials on COPD-patients. Recently, a large trial confirmed that COPD-patients who don't meet classic indication criteria, and have moderate desaturation at rest or during exercise, do not benefit from oxygen therapy. Also the significant technical evolution of LTOT devices has improved its application. Areas covered: A literature research was performed in pubmed regarding home oxygen therapy (terms: LTOT, ambulatory oxygen therapy, short burst oxygen therapy, nocturnal oxygen therapy). Expert commentary: LTOT proved a survival benefit for COPD patients about 30 years ago. Whether the results of these trials are still valid for patients under modern treatment guidelines remains unknown. Nevertheless, the classic indication criteria for LTOT still persist in guidelines, since there is a lack of updated evidence for the effects of LTOT in more severe hypoxemic patients.

Oxygen therapy devices and portable ventilators for improved physical activity in daily life in patients with chronic respiratory disease

INTRODUCTION

Patients with hypoxemia and chronic respiratory failure may need to use oxygen therapy to correct hypoxemia and to use ventilatory support to augment alveolar ventilation, reverse abnormalities in blood gases (in particular hypercapnia) and reduce the work of breathing. Areas covered: This narrative review provides an overview on the use of oxygen therapy devices or portable ventilators for improved physical activity in daily life (PADL) as well as discusses the issue of lower mobility in daily life among stable patients with chronic respiratory disease who present indication for long-term oxygen therapy (LTOT) or home-based noninvasive ventilation (NIV). A literature review of these concepts was performed by using all related search terms. Expert commentary: Technological advances led to the development of light and small oxygen therapy devices and portable ventilators which aim to facilitate patients' mobility and ambulation. However, the day-by-day dependence of a device may reduce mobility and partially impair patients' PADL. Nocturnal NIV implementation in hypercapnic patients seems promising to improve PADL. The magnitude of their equipment-related physical inactivity is underexplored up to this moment and more long-term randomized clinical trials and meta-analysis examining the effects of ambulatory oxygen and NIV on PADL are required.

How do respiratory patients perceive oxygen therapy? A critical interpretative synthesis of the literature

Oxygen therapy is a common intervention in health care worldwide; yet, despite universal use, it is evident through poor practice that oxygen is often prescribed and administered injudiciously. It is proposed that possibly an influencing culture presides, whereby oxygen is often poorly understood and uncertainty regarding its use exists. It is unclear where the origins of this culture lie but exploring perceptions may enlighten the problem. A review of the literature was undertaken to establish what is already known about this elusive phenomenon. The paucity of any direct evidence regarding perceptions of oxygen directed the review to utilize a critical interpretative synthesis (CIS). The aim of this study was to explore how respiratory patients perceive oxygen therapy. A systematic search in Medline, Cinahl, Embase, British Nursing Index and PsychInfo yielded 1514 studies of which 42 were selected to consider the review question. The CIS allowed evidence from across studies to synthesize existing and new interpretations of data related to patients' perceptions of oxygen therapy. Synthetic constructs then informed the synthesizing arguments, namely positive - feeling safe, enabler and comforter; negative - fear, oxygen versus self, restriction and embarrassment; and impartiality - mixed blessings. The findings are divergent, and at times contradictory. There appears uncertainty among patients regarding the purpose and benefits of oxygen therapy, though an underlying faith in health-care professionals is apparent. This faith seems to foster acceptance of a life-changing therapy, despite the impact, burden and incomplete understanding. There is a clear need for further research regarding these elusive perceptions in order to improve clinical practice in respect of oxygen.

Long-term oxygen therapy

Long-term oxygen therapy (LTOT) has been shown to reduce pulmonary hypertension and improve survival in patients with chronic obstructive pulmonary disease and resting hypoxemia (reduced arterial partial pressure of oxygen ≤55 mmHg). However, the benefit of its use for chronic pulmonary diseases other than chronic obstructive pulmonary disease as well as for nonpulmonary conditions is debatable. Its role in patients with mild hypoxemia (reduced arterial partial pressure of oxygen >55 mmHg at rest) is presently being investigated in the LOTT. A meta-analysis of four controlled trials reporting the role of LTOT in patients with either nocturnal desaturation or daytime moderate hypoxemia found no difference in survival between patients on LTOT than those without. Advances in oxygen delivery and conservation devices have made domiciliary oxygen therapy more practical and popular for patients. There still remain concerns with the actual compliance of therapy among the needy patients.

A crossover study of short burst oxygen therapy (SBOT) for the relief of exercise-induced breathlessness in severe COPD

BACKGROUND

Previous small studies suggested SBOT may be ineffective in relieving breathlessness after exercise in COPD.

METHODS

34 COPD patients with FEV1 <40% predicted and resting oxygen saturation ≥93% undertook an exercise step test 4 times. After exercise, patients were given 4 l/min of oxygen from a simple face mask, 4 l/min air from a face mask (single blind), air from a fan or no intervention.

RESULTS

Average oxygen saturation fell from 95.0% to 91.3% after exercise. The mean time to subjective recovery was 3.3 minutes with no difference between treatments. The mean Borg breathlessness score was 1.5/10 at rest, rising to 5.1/10 at the end of exercise (No breathlessness = 0, worst possible breathlessness = 10). Oxygen therapy had no discernable effect on Borg scores even for 14 patients who desaturated below 90%. 15 patients had no preferred treatment, 7 preferred oxygen, 6 preferred the fan, 3 preferred air via a mask and 3 preferred room air.

CONCLUSIONS

This study provides no support for the idea that COPD patients who are not hypoxaemic at rest derive noticeable benefit from oxygen therapy after exercise. Use of air from a mask or from a fan had no apparent physiological or placebo effect.

Medical therapy for chronic obstructive pulmonary disease in 2007

Medical treatment for patients with stable chronic obstructive pulmonary disease (COPD) has evolved significantly over the past 2 decades. Current World Health Organization recommendations suggest a stepwise approach to therapy depending upon disease severity. As-needed use of short-acting bronchodilators is recommended for patients with mild disease. Scheduled dosing of bronchodilators is recommended for patients with more advanced disease. Inhaled beta-agonists and anti-cholinergic agents in combination have proved to be more effective than either agent alone. Long-acting preparations are associated with better disease control and have not been associated with tachyphylaxis. Inhaled corticosteroids are useful for reducing the frequency of exacerbations in patients who experience one or more episodes per year. Oxygen therapy is clearly beneficial in patients with advanced COPD and chronic respiratory failure, and its potential benefits in less severe disease are currently being studied. Pulmonary rehabilitation benefits patients with mild-to-severe disease, although the greatest benefits have been demonstrated in those with moderate COPD. New ultra-long-acting inhaled bronchodilators, phosphodiesterase inhibitors, protease inhibitors, and retinoids intended to promote tissue regeneration are currently being evaluated in clinical trials as future therapeutic agents.