A double-blind trial of nocturnal supplemental oxygen for sleep desaturation in patients with chronic obstructive pulmonary disease and a daytime PaO2 above 60 mm Hg. Effect of long-term oxygen therapy on survival in patients with chronic obstructive pulmonary disease with moderate hypoxaemia. Long-term oxygen therapy stops the natural decline of endurance in COPD patients with reversible hypercapnia. A randomized trial of nocturnal oxygen therapy in chronic obstructive pulmonary disease patients.
The efficacy of nasal oxygen during sleep was evaluated in patients with COPD, episodic rapid eye movement sleep desaturation, and a daytime PaO2 greater than 60 mm Hg. The double-blind, randomized 3-yr trial used nasal oxygen versus room air in two groups of nocturnal sleep desaturating subjects. The setting was the outpatient chest clinic of a Veterans Affairs Medical Center. There were 51 patients with moderate to severe COPD, daytime PaO2 greater than or equal to 60 mm Hg: 38 with proven REM sleep desaturation and 13 without desaturation. Nocturnal oxygen at 3 L/min was delivered by concentrator to 19 desaturating subjects, and room air at 3 L/min was delivered by defective concentrator to the remaining 19 desaturating subjects. There was no gas therapy for the 13 nondesaturating subjects. The nocturnal desaturator group who received supplemental oxygen during sleep over 36 months showed a significant downward trend in pulmonary artery pressure (-3.7 mm Hg) compared with desaturating patients treated with room air (+3.9 mm Hg). Nonvascular parameters of hypoxia, such as hemoglobin and red blood cell mass, did not differ between the sham- and oxygen-treated groups. Mortality was decidedly higher in the desaturating patients compared with non-desaturating subjects, but there was no significant difference between oxygen- and sham-treated desaturating subjects. We conclude that nasal supplemental oxygen used during sleep to reverse episodic desaturation in COPD patients whose daytime PaO2 is above 60 mm Hg has a beneficial effect in reducing pulmonary artery pressure.(ABSTRACT TRUNCATED AT 250 WORDS) To date only two controlled studies have been published on the effects of domiciliary oxygen treatment on survival in patients with chronic obstructive pulmonary disease (COPD) with advanced respiratory failure. The survival in such patients despite oxygen treatment remains poor. The prescription of long term oxygen therapy (LTOT) in less severe disease remains controversial. The aim of this study was to evaluate the rationale for prescribing oxygen to patients with COPD with moderate hypoxaemia.
                One hundred and thirty five patients with COPD, with PaO2 7.4-8.7 kPa (56-65 mmHg) and advanced airflow limitation (mean (SD) forced expiratory volume in one second (FEV1) 0.83 (0.28) 1), were randomly allocated to a control (n = 67) and LTOT (n = 68) group. The patients were followed every three months for at least three years or until death.
                The cumulative survival rate was 88% at one year, 77% at two years, and 66% at three years. No significant differences were found in survival rates between patients treated with LTOT and controls, nor did longer oxygen use (over 15 hours per day) improve survival. Younger age, better spirometric values, and higher body mass index predicted better survival.
                Domiciliary oxygen treatment does not prolong survival in patients with COPD with moderate hypoxaemia. Airway limitation seems to determine survival in this group of patients. Respiratory muscle weakness is one of the most important causes of hypercapnia in patients with COPD. There is evidence that stable hypercapnic patients will benefit from long-term oxygen therapy (LTOT).
                The prognostic role of reversible hypercapnia in COPD is still unclear. Early implementation of LTOT in these patients may influence endurance time and mortality.
                In this pilot study, we investigated 28 patients (26 males, 49-74 years) with COPD, advanced airflow limitation [forced expiratory volume in 1 s (percentage of predicted value) 40.8 +/- 10.2] and mild hypoxaemia (pO(2) 66.5 +/- 6.3 mm Hg). All patients had developed a moderate reversible hypercapnia during an acute exacerbation or during exercise testing (peak pCO(2) 48.0 +/- 2.5 mm Hg). Patients were allocated randomly to a control group (n = 14) or an LTOT group (n = 14). The two groups were well matched in terms of physiological data. Lung function, endurance time (cycle ergometer), dyspnoea score, blood gases and LTOT compliance were measured at baseline and every 6 months over a period of 3 years.
                Endurance time increased from 6.4 +/- 2.7 min at baseline to 7.1 +/- 2.7 min after 1 year in the LTOT group and decreased from 6.1 +/- 3.0 to 4.9 +/- 3.8 min in the controls (p < 0.05). After 1 year, the end-exercise dyspnoea score was significantly lower in the LTOT group (4.5 +/- 1.5) than in the controls (5.7 +/- 1.9).
                COPD patients with reversible hypercapnia and mild hypoxaemia benefit from LTOT in terms of endurance time and a reduction of exertional dyspnoea after 1 year.
                Copyright 2004 S. Karger AG, Basel The beneficial effects of nocturnal oxygen therapy (NOT) in chronic obstructive pulmonary disease (COPD) patients with mild-to-moderate daytime hypoxaemia (arterial oxygen tension (Pa,O2) in the range 7.4-9.2 kPa (56-69 mmHg)) and exhibiting sleep-related oxygen desaturation remains controversial. The effectiveness of NOT in that category of COPD patients was studied. The end points included pulmonary haemodynamic effects after 2 yrs of follow-up, survival and requirement for long-term oxygen therapy (LTOT). Seventy-six patients could be randomized, 41 were allocated to NOT and 35 to no NOT (control). The goal of NOT was to achieve an arterial oxygen saturation of >90% throughout the night. All these patients underwent polysomnography to exclude an associated obstructive sleep apnoea syndrome. The two groups exhibited an identical meansD daytime Pa,O2 of 8.4+/-0.4 kPa (63+/-3 mmHg) at baseline. Twenty-two patients (12 in the NOT group and 10 in the control group, p=0.98) required LTOT during the whole follow-up (35+/-14 months). Sixteen patients died, nine in the NOT group and seven in the control group (p=0.84). Forty-six patients were able to undergo pulmonary haemodynamic re-evaluation after 2 yrs, 24 in the NOT and 22 in the control group. In the control group, mean resting pulmonary artery pressure increased from 19.8+/-5.6 to 20.5+6.5 mmHg, which was not different from the change in mean pulmonary artery pressure in the NOT group, from 18.3+/-4.7 to 19.5+/-5.3 mmHg (p= 0.79). Nocturnal oxygen therapy did not modify the evolution of pulmonary haemodynamics and did not allow delay in the prescription of long-term oxygen therapy. No effect of NOT on survival was observed, but the small number of deaths precluded any firm conclusion. These results suggest that the prescription of nocturnal oxygen therapy in isolation is probably not justified in chronic obstructive pulmonary disease patients.
Long-term home oxygen therapy improved survival in a selected group of COPD patients with severe hypoxaemia (arterial PaO2 less than 55 mm Hg (8.0 kPa)). Home oxygen therapy did not appear to improve survival in patients with mild to moderate hypoxaemia or in those with only arterial desaturation at night.