The Science Journal of the American Association for Respiratory Care

2000 OPEN FORUM Abstracts

NOCTURNAL OXYGEN DESATURATION OCCURS IN COPD PATIENTS RECEIVING SUPPLEMENTAL OXYGEN

Jonathan B. Waugh, PhD, RRT,* Becky Christian,** David Lain, PhD, RRT+ *University of Alabama at Birmingham, Birmingham, AL ** Heartland Home Care, Kennett, MO + Department of Clinical Programs, Respironics, Inc

Background: Supplemental O2 has been shown to increase O2 saturation in patients with chronic obstructive pulmonary disease. Oxygen has been used to reduce nocturnal O2 desaturation in the COPD population. Our clinical experience indicated patients with COPD were still at risk for hypoventilation and respiratory dysfunction during sleep in spite of supplemental O2 use. We measured nocturnal O2 saturation levels of COPD subjects receiving O2 to document desaturation periods and measure their significance.

Methods:
23 volunteer subjects were enrolled for analysis of data that was routinely observed as part of their normal home care protocol for monitoring the utility of prescribed O2 therapy. Oxygen saturation (SpO2) was monitored using a Respironics 920M pulse oximeter.

Results:
Descriptive data included mean O2 flow rate = 2.5 L/min, mean patient monitoring period = 438 min., high SpO2 group mean = 98%, low SpO2 group mean = 76%, and average SpO2 group mean = 93%. The group mean for the amount of time each individual spent at their lowest SpO2 was 19.7 min. and the average time spent at saturations below 88% (SpO288Min) was 73 min. A binomial test was performed on a dichotomous form of the SpO288Min data that yielded p<0.001. A SpO2<88% for a total of 60 min. or longer constituted an unacceptable therapeutic support event (equal to a value of 1, whereas SpO2<88% for less than 60 min. was assigned a value of zero.

Conclusions:
This group of subjects with COPD were at risk for nocturnal desaturation especially during REM sleep. Supplemental O2 sufficient for waking ventilation and maintaining an average SpO2>90% was not able to avert remarkable periods of nocturnal desaturation. Although supplemental O2 may reduce daily O2 desaturation by some degree in COPD patients, it may be inadequate to prevent serious nocturnal desaturation and sleep quality disturbance.
Sponsored by Respironics, Inc., Murrysville, PA

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