THE ASSESSMENT TASK

The Assessment Task

The Assessment Task

Introduction

Long-term oxygen treatment (LTOT) prolongs life in patients with chronic obstructive pulmonary disease (COPD) and severe resting hypoxemia. Although this benefit is proven by clinical trials, scientific research has not provided definitive guidance regarding who should receive LTOT and how it should be delivered. Deficiencies in knowledge and in current research activity related to LTOT are especially striking in comparison to the importance of LTOT in the management of COPD and the associated costs (Nici & Donner et al. 2006: 1390). The National Heart, Lung, and Blood Institute, in collaboration with the Centers for Medicare and Medicaid Services, convened a working group to discuss research on LTOT.

Participants in this meeting identified specific areas in which further investigation would likely lead to improvements in the care of patients with COPD or reductions in the cost of their care (Mur-Veeman et al, 2004: 227). The group recommended four clinical trials in subjects with COPD: (1) efficacy of ambulatory O2 supplementation in subjects who experience oxyhemoglobin desaturation during physical activity but are not severely hypoxemic at rest; (2) efficacy of LTOT in subjects with severe COPD and only moderate hypoxemia; (3) efficacy of nocturnal O2 supplementation in subjects who show episodic desaturation during sleep that is not attributable to obstructive sleep apnea; and (4) effectiveness of an activity-dependent prescription for O2 flow rate that is based on clinical tests performed at rest, during exercise, and during sleep (Morgan & Singh, 2003).

Chronic obstructive pulmonary disease (COPD) kills approximately 120,000 Americans each year (1). Disease prevention by smoking cessation is critical for the control of COPD because there is no cure for established disease. Nonetheless, there are four interventions that likely prolong the survival of patients with serious COPD. Retrospective studies suggest that pneumococcal and influenza vaccinations reduce mortality (Koff & Jones et al 2009: 1031). Intensive management of those hospitalized for acute exacerbations of COPD probably averts death in many gravely ill patients. In particular, there is apparent benefit from noninvasive positive-pressure ventilation in those with respiratory failure. Lung volume reduction surgery improves survival in selected patients with severe emphysema. Finally, long-term oxygen treatment (LTOT) significantly reduces mortality in patients with COPD and severe resting arterial hypoxemia (Holman, 2000: 526). Of these interventions, LTOT has the greatest proven impact on public health. Prospective studies of immunizations are lacking, intensive care during hospitalization does nothing to diminish future risk of exacerbation, and lung volume reduction surgery is indicated for only a small minority of patients with COPD and is available at only a limited number of centers (Garcia-Aymerich et al. 2007: 1462). On the other hand, LTOT is indicated for many patients with severe disease, yields robust effects on survival, and is widely available through a national network of suppliers and a Medicare coverage policy that is consistent with existing clinical trial data.

Despite the importance of LTOT in the management of COPD, there are many deficits in our knowledge regarding its mechanisms of action, indications for prescription, ...