The history of long-term oxygen therapy.

Early investigators of oxygen therapy reported an overall clinical improvement in persons with chronic lung disease who received oxygen. Later American and British studies showed that oxygen therapy could decrease pulmonary vascular pressures and red cell mass in some patients with pulmonary hypertension and polycythemia secondary to severe hypoxemia. The British Research Council Study showed that survival rates were significantly higher in patients receiving 15 hours of oxygen than in those receiving no oxygen. The Nocturnal Oxygen Therapy Trial showed that survival rates for persons receiving continuous oxygen therapy has also been shown to improve exercise tolerance and neuropsychiatric function. Further advances in the administration of long-term oxygen therapy and studies in the criteria for its use are needed.     

Nonmedical hazards of long-term oxygen therapy.

Oxygen is neither explosive nor combustible, but because it does support combustion its potential fire hazards must be recognized. The principal fire hazards of long-term oxygen therapy are (1) the ignition potential of plastic delivery devices and (2) oxygen leaks (a) from high-pressure cylinders and cryogenic reservoirs into nearby combustible materials; (b) from oxygen concentrators, which are electrical devices; and (c) within piping systems. We found that with 100% oxygen a nasal cannula ignited and burned in about 2 minutes. With 60% oxygen the burning rate was slower, and with 40% the cannula did not ignite. We also studied various sizes of oxygen delivery tubing and found that tubing 3/16" or smaller with 40% oxygen flowing self-extinguished a flame. The safe use of oxygen in the home requires that patients and their families be knowledgeable about the hazards.     

Cost-effectiveness and efficacy in long-term oxygen therapy

Changes to the new home oxygen service have raised awareness among health professionals of the potential hazards and benefits of oxygen therapy. Annette Duck reviews the use of long-term oxygen therapy and highlights the importance of assessment in selecting both patients and suitable delivery systems.     

Historical highlights of long-term oxygen therapy

The story of the development of oxygen and its role in mitigating the ravages of chronic stable hypoxemia have been fascinating. Today, over one million Americans receive home oxygen each day, usually for COPD, from one of the three available systems. The future requires less expensive, highly portable, and practical devices for use during all activities of daily living.     

Patients' experiences of long-term oxygen therapy

The aim of this study, which was undertaken in patients' homes in Sweden, was to describe patients' experiences in the self-management of continuous oxygen therapy and their view of managing their chronic disease. A phenomenological approach was used. Data were collected in interviews and analysis produced four categories. The findings show that the patients need help with relief for different physiological and psychological difficulties and from social isolation. The patients had insufficient resources for daily life. They were restricted to their homes, had mobility problems and were dependent upon a continuous life rhythm. Dependence upon another family member is therefore an important factor. But even with the presence of a significant other, social isolation is prevalent.     

The demographics and economics of long-term oxygen therapy

Home oxygen therapy represents a scientifically validated and universally accepted therapeutic regimen for the treatment of chronic hypoxemia secondary to COPD. The clinical benefits of home oxygen, including a decrease in morbidity and often a concomitant increase in the quality of life have been repeatedly confirmed through rigorous worldwide trials, studies, and investigations. However, since home oxygen is an expensive treatment modality, important questions continue to be raised about the overall cost-benefit of the intervention. Such scrutiny is expected to continue, especially in the United States, as the entire issue of health care cost-containment remains atop the domestic political agenda. Providers of home oxygen therapy have traditionally realized quite favorable reimbursement for home oxygen equipment, especially for those patient-customers covered under the Medicare program. However, recent Medicare reimbursement reductions of more than 30% have raised serious questions about the ability of home oxygen providers, especially those with annual revenues less than $1 million, to sustain their historical high level of support services to home oxygen patient-customers. Of particular concern is the economic hardship of supplying portable oxygen, especially for those patient-customers with unusually high ambulatory needs. The use of oxygen-conserving devices is viewed by some as one strategy to better control the costs of supplying portable oxygen, although there are those who still question whether or not oxygen-conserving devices can effectively forestall arterial oxygen desaturation across the entire spectrum of ambulation. Given the evidence now being reported that compliance in using home oxygen as prescribed may well be much lower than originally believed, the time is probably right to revisit the role played by home oxygen providers in determining continuing need through the performance of periodic reassessments. Such reassessments, if designed according to prescribed and validated protocols and conducted by home respiratory therapists under orders of the prescribing physician, would be a valuable tool to ensure continued medical need and identifying noncompliance. This would help ensure that those needing and using home oxygen would continue to receive the benefit. At the same time, patient-customers who, for one reason or another, stop using their oxygen equipment despite repeated encouragement, would have the equipment removed. The net result would be that reimbursement dollars currently wasted on home oxygen equipment that is not being used could be reallocated for those patient-customers willing and able to use the equipment as prescribed.     

Delivery systems for long-term oxygen therapy

Table 5 summarizes my current perspective on home oxygen delivery systems in the United States. As I already indicated, scoring for cost and labor may be very different in other countries. As noted, all things considered, today the most reasonable system for home oxygen therapy is the concentrator. Problems with FIO2, liter flow, and portability are clearly overshadowed by cost, labor, ease of use, and lack of potential hazard, as well as potential for future innovation. I would expect with future development that the concentrator will score higher on FIO2, liter flow, and portability. As a result of the anticipated large number of patients worldwide expected to require home oxygen therapy, ongoing improvement in this technology will be evident in the next few years.     

A nationwide system of long-term oxygen therapy: the Polish experience

Poland's Institute of Tuberculosis and Lung Diseases oversees 49 provincial clinics, which provide and monitor LTOT for patients with COPD, interstitial pulmonary fibrosis, and other pulmonary conditions. Because of limited resources, eligibility for LTOT is fairly strictly defined, and LTOT equipment is distributed to and retained only by nonsmoking patients who continue to demonstrate need of the equipment (i.e., those who have ongoing hypoxemia that can benefit from LTOT). This national LTOT system provides a large, nonselected population suitable for LTOT research, and recent studies have produced important data regarding survival, pulmonary hemodynamics, and the effect of withdrawing LTOT from patients whose oxygenation has recovered to above the LTOT qualification level of PaO2 < or = 55 mm Hg.     

Effects of long-term oxygen therapy on mortality and morbidity

In general, based on the above studies of the effects of supplemental oxygen on reducing mortality and improving sleep and exercise function in certain patient groups, patients whose disease is stable on a full medical regimen with PaO2 < or = 55 mm Hg (SaO2 < or = 88%) should be considered for LTOT. Patients with PaO2 of 55-59 mm Hg with signs of tissue hypoxemia (i.e., cor pulmonale, polycythemia, impaired cognition) should also be considered for LTOT. Oxygen therapy should also be considered for those who desaturate during sleep or exercise. These guidelines have been adopted by Medicare as reimbursement criteria and have also been endorsed by the American Thoracic Society. Indications for LTOT endorsed by the American Thoracic Society and published in the "Standards for the Diagnosis and Care of Patients with COPD" are shown in Table 6. More research is required to investigate the use of supplemental oxygen in patients who suffer nocturnal desaturation but do not have signs of end organ dysfunction, those who have an improvement in dyspnea with supplemental oxygen, and in normoxemic patients with impaired exercise performance who improve while inspiring supplemental oxygen.     

Long-term oxygen therapy vs long-term ventilatory assistance

The use of positive-pressure nasal ventilation in combination with LTOT in stable COPD patients with hypercapnic respiratory failure controls hypoventilation and improves daytime ABGs, sleep, and quality of life. Nasal ventilation in COPD is unlikely to produce benefit unless used with supplemental oxygen therapy at night. The patients who show the greatest reduction in overnight PaCO2 with ventilation are the patients most likely to benefit from long-term ventilatory support. Although there is now evidence for short-term benefit from NPPV in hypercapnic COPD, large multicenter studies with survival, exacerbations, and hospital admissions as the primary end points are required to evaluate longer-term effects of this potentially important intervention.     

Surveillance system for nosocomial infections due to drug-resistant organisms in Japan and other countries

The national nosocomial infection surveillance systems in Japan as well as American-European countries were overlooked. The NNIS/CDC system, which started in 1970, is the only continuous surveillance system focusing on the improvement of prevention of nosocomial infection in US. Other surveillance systems being started in 1980's in European countries were prevalence studies, most of which studied prevalence of nosocomial infections and audited drug-resistance organisms. The Japanese nosocomial infection surveillance system, which started in 2000 by Ministry of Health and Welfare, is attempting to promote system improvement of prevention of nosocomial infection where a risk-adjusted outcome was used as an evaluation criteria.     

Clinical guidelines for tuberculosis of Japan compared with those of other countries

The Standards of Tuberculosis Treatment of Japan issued by the government and some related announcements by the Japanese Society of Tuberculosis are compared with the Recommendations of American Thoracic Society, CDC, and Infectious Diseases Society of America, and the Treatment Guidelines of WHO. International Standards of Tuberculosis Care by Tuberculosis Coalition for Technical Assistance is also referenced as appropriate. Although they are different in many ways in minor points, they share the basic principle of using the regimen of the initial phase with four drugs followed by the maintenance with two or three drugs including rifampicin and isoniazid for new cases. They also stress the importance of support of patients for treatment completion, but the ways to realize it are delicately different among them.     

Cognitive decline in patients with long-term domiciliary oxygen therapy

Cognitive and psycho-physiological condition in patients with long-term domiciliary oxygen therapy (DOT) remains uncertain. A cross sectional analysis was performed to investigate the age-related changes in cognitive and psycho-physiologic functions in patients with chronic respiratory failure receiving long-term DOT. Two expert practitioners visited the patient's home and examined them for analysis of cognitive function, emotional status, physical activity and degree of dyspneic sensation. One hundred and thirty-five patients completed the study. Control data from a cohort of 718 community dwellers were also included in this study. Male patients had significantly higher rates of chronic obstructive pulmonary disease (71% vs 47%, p = 0.001), lower values of forced expiratory volume in one second (FEV1.0) % (49.7 +/- 10.3 [standard deviation, S.D.] vs 66.0 +/- 7.5% predicted, p = 0.002) and higher Borg score, an indicator of dyspneic sensation, during daily exercise (3.2 +/- 0.8 [S.D.] vs 1.4 +/- 0.6, p = 0.01) compared with female patients. Linear regression analysis based on mean Mini-Mental State Examination scores, an indicator of cognitive function, showed that age-related cognitive decline was more pronounced in female patients than in female controls (-0.524/year, R2 = 0.426 vs -0.120/year, R2 = 0.027, p < 0.0001), while there was no significant difference between male patients and male controls (-0.156/year, R2 = 0.054, vs -0.077/year, R2 = 0.016, p = 0.231). These results demonstrate that age-related cognitive decline is more exaggerated in female patients receiving long-term DOT which should be taken into consideration in caring for patients with chronic respiratory failure.     

慢性呼吸衰竭患者长期家庭氧疗的护理随访研究

目的:评估慢性呼吸衰竭患者长期氧疗的依从性,分析影响患者依从性的因素.方法:对120例慢性呼吸衰竭患者长期氧疗依从性情况进行问卷调查并进行12个月的随访,分析依从性对患者的影响.结果:120例患者中,44例依从性较好,76例依从性差.氧疗时间、教育程度及噪声是其影响因素.结论:长期氧疗能减轻患者的二氧化碳潴留和肺部过度充气,改善患者的呼吸功能.