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Aim: Demand oxygen delivery systems (DODSs) were developed to secure the mobility of patients requiring oxygen therapy. The aim of the present study was to compare the efficacy of two currently available DODS with continuous oxygen administration (CONT).
Patients: Thirteen patients with COPD (mean [± SD] FEV^sub 1^, 28 ± 5.2% predicted; mean PO^sub 2^, 56.4 ± 8.1 mm Hg [breathing room air]).
Intervention: Treatment for 30 min with CONT at a flow rate of 2 L/min, with the DODSs Oxytron 3 (Weinmann; Hamburg, Germany) or DeVilbiss EX 3000 (Somerset, PA) in random sequence. Arterialized blood samples were obtained from a hyperaemized ear lobe after 15 and 30 min.
Results: After 15 min, no significant differences in PO^sub 2^ or arterial oxygen saturation (SaO^sub 2^) were observed. In comparison with CONT (mean PO^sub 2^, 70.5 ± 10.4 mm Hg; mean SaO^sub 2^, 94.8 ± 2.13%), oxygenation with the Oxytron 3 (mean PO^sub 2^, 66.3 ± 10.3 mm Hg; mean SaO^sub 2^, 93.5 ± 2.6%) was significantly less after 30 min when measured independently by blood gas analysis and pulse oximetry. The DeVilbiss EX 3000 (mean PO^sub 2^, 69.1 ± 12.0 mm Hg; mean SaO^sub 2^, 94.5 ± 3.2%) and CONT showed no differences.
Conclusions: PO^sub 2^ did not reach equilibrium after 15 min of treatment with the DODSs. The titration of a patient to a DODS is recommended, since simply accepting the manufacturer's information on oxygen equivalent does not guarantee an adequate supply of oxygen. (CHEST 2005; 128:2082-2087)
Key words: COPD; oxygen delivery and consumption; oxygen therapy
Abbreviations: CONT = continuous oxygen administration; DODS = demand oxygen delivery system; SaO^sub 2^ = arterial oxygen saturation
The basis for long-term oxygen therapy was provided by studies from the Nocturnal Oxygen Therapy Trial Group1 and the Medical Research Council Working Party,2 published in 1980 and 1981, respectively, which demonstrated that the duration of the daily application of oxygen is associated with a survival advantage for chronically hypoxemic COPD patients who were receiving long-term oxygen therapy.
With continuous long-term oxygen therapy via nasal prongs appreciably more oxygen is used up than is actually needed, since only a portion of the oxygen delivered reaches the patient's alveoli. In view of the widespread application of long-term oxygen therapy, oxygen...