[Long-term oxygen therapy (LTOT)--what should physicians, homecare-providers and health insurance companies know?]

Long-Term Oxygen Therapy

BACKGROUND

Long-term oxygen therapy (LTOT) is an established treatment for patients with chronic hypoxemia. Its scientific basis is derived mainly from two trials from the early 1980s that showed a survival advantage for patients with chronic obstructive pulmonary disease (COPD) treated with LTOT. Robust data are not available for other diseases associated with hypoxemia.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed.

RESULTS

The use of LTOT for 15 to 16 hours per day (or, better, 24 hours per day) is recommended in current guidelines for patients with chronic hypoxemia (PaO2 ≤ 55 mm Hg) because this treatment was found to be associated with a lower mortality rate compared to no LTOT (33% vs. 55%, p <0.05) based on data from the early 1980s. In the short term, oxygen administration to a hypoxemic patient can improve oxygen saturation by nine percentage points and improve physical performance to a clinically relevant extent (6-minute walking test: + 37 m, p <0.001). The available data do not support the use of LTOT for normoxemic patients. LTOT should only be administered for strict indications, in accordance with the guidelines, and only in a form suitable for the individual patient. Skin burns can occur as a side effect of LTOT because of contact explosions with any type of fire.

CONCLUSION

The acquisition of further robust data would be desirable, particularly with respect to patient-relevant outcome parameters including quality of life, performance status, and mortality. Moreover, the German guidelines on oxygen therapy need to be updated.

Benefits of an oxygen reservoir cannula versus a conventional nasal cannula during exercise in hypoxemic COPD patients: a crossover trial

BACKGROUND

The Oxymizer® is a special nasal cannula that provides a higher luminal diameter in combination with an incorporated oxygen (O2) reservoir. It is assumed that a higher O2 concentration can be delivered breath by breath in order to increase oxygenation.

OBJECTIVE

We aimed to investigate the effects of the Oxymizer on endurance time in comparison to a conventional nasal cannula (CNC).

METHODS

Forty-three patients with severe chronic obstructive pulmonary disease (COPD, age 60 ± 9 years, FEV1 37 ± 16% pred.) and indications for LTOT were recruited during pulmonary rehabilitation for this cross-over study. After an initial maximal incremental cycle test, all patients performed 4 cycling endurance time tests at 70% of their peak work rate (twice with the Oxymizer and twice with a CNC, in reverse order).

RESULTS

The endurance time was significantly higher when patients cycled while using the Oxymizer in comparison to while using the CNC [858 ± 754 vs. 766 ± 652 s; between-group difference 92 s (95% confidence interval 32-152), p < 0.001]. In addition to a longer cycling duration, O2 saturation at isotime was significantly higher with the Oxymizer (93.5 ± 5.4 vs. 90.4 ± 5.3%; p = 0.027). Furthermore, there was a positive correlation (r = 0.427, p = 0.002) between the O2 flow rate and improvements in the constant work rate test, showing greater improvements in favor of the Oxymizer in patients with a higher demand for O2 (≥ 4 liters/min).

CONCLUSION

We show that O2 delivery via the Oxymizer is superior to a CNC with regard to endurance capacity and oxygenation during exercise in patients with severe COPD. It seems that patients with a higher demand for O2 (≥ 4 liters/min), in particular, may benefit more from the use of the Oxymizer.