Background: Historical wisdom has recommended up to 50 ft (15.24 m) of tubing based on the oxygen cylinder delivery system. Yet, many individuals may store their stationary systems in one area of the home and conduct their activities at distances by adding additional tubing. The aim of this study was to discriminate at what lengths clinically relevant decreases in flow greater than 20% occurred.
Methods: Plastic tubing was added at 25 ft (7.62 m) intervals connected via a swivel adapter up to 200 ft (60.96 m) to a cylinder, concentrator and liquid stationary oxygen system to simulate a home oxygen environment. Flows of 1-5 L/min were set then measured via the Timemeter 200 after each segment of additional tubing.
Results: Output from the cylinder with regulator/flowmeter was greatly diminished as tubing and flowrate was increased which resulted in clinically significant reductions in flow at 2 L/min for tubing lengths greater than 100 ft (30.48 m). The oxygen concentrator had little flow reduction at 1 or 2 L and more flow loss at higher tubing lengths with 3, 4 and 5 L/min. Liquid oxygen was only mildly reduced at 125 ft (38.10 m) of tubing and 4 or 5 L of flow. Neither the concentrator nor liquid oxygen delivery units had flow reductions greater than 13.5 and 4.0%, respectively, at 2 L/min with 200 ft (60.96 m) of tubing. SUMMARY AND RECOMMENDATIONS: Tubing length up to 200 ft (60.96 m) could be utilized for providing patient home oxygen with Puritan Bennett style liquid oxygen. We recommend consideration of tubing lengths up to 200 ft (60.96 m) and up to 3 L/min or 100 ft (30.48 m) at 4-5 L/min for Invacare 5 and similar oxygen concentrators; however flow delivery should be verified by the manufacturer. The cylinder regulator/flowmeter system suffered the greatest flow loss. Flows of 1-2 L/min can be clinically maintained with up to 100-ft (30.48 m) of tubing. This study brings clarity of when tubing can be lengthened which may enhance movement within the home and lessen constraints.