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Sleep Apnea/oxygen during sleep study


QUESTION: My husband has COPD and is on oxygen at night after an overnight pulse oxygen study.He recently did an overnight sleep study and was told that of the 242 minutes of sleep time he was at or below an 88% oxygen level for 136 minutes or 56% of his sleep time.They didn't seem too concerned and felt the CPAP would help. He was diagnosed with OSA with mild to moderate hypoxemia. I have 2 main questions. First if a person is on nightly oxygen shouldn't the sleep study have been done while he was using his oxygen? Secondly he needs to wait 3 weeks for a titration study and then another week for the data to be processed. Should we be concerned about this low level of oxygen for this long of a time? He probably won't even know if it's working for a month or two after he starts the machine therapy. Any thoughts or suggestions? Thank you.

ANSWER: Maureen:  before I can address your questions, please obtain a copy of your husband's sleep study report (a preliminary one will do fine if the final signed report is not available) so I can take a closer look at the situation.  I'm specifically interested in the AHI (Apnea-Hypopnea Index) and/or the RDI (Respiratory Disturbance Index) numbers and what if any breakdown they give on the report having to do with body position and numbers of disturbances in those body positions.

Do you by chance know the results of that overnight pulse oximetry study?  If so, if would help if I can learn of the data from that study.

Ill look forward to hearing back.  Hopefully I can help both you and your husband in some way...

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QUESTION: The overnight pulse ox test showed 18 min > 88%. This was the only info we received. (We felt that that was a underrepresentation as he didn't sleep much that night. That is when the Dr. felt he should continue using oxygen at night.  
On the overnight sleep study "Respiratory analysis demonstrated 2 obstructive apneas, 0 mixed apnea and 0 central apnea. The apnea index was 0.5. There were 57 hypopneas, with a total apnea index of of 14.6. The patient spent 0.4% of total sleep time in the supine position, with a supine AHI of 60.0 versus a non-supine AHI of 14.4.  The REM AHI was 44.0 versus a non-REM AHI of 4.9  Baseline oxygen saturation was 95%  The lowest saturation was 72% with 56.6 of sleep time spent at or below 88%.  There were 136.6 minutes of total sleep time spent at or below 88%.  There were 54 desaturations. Respiratory arousal index was 5.7. Mild to moderate intermittent snoring was noted." Hope this is the information you need.

Maureen: thanks for sharing the data and yes, that's what I needed.  The results you shared are indeed consistent with those seen in obstructive sleep apnea syndrome (OSAS) and are numerically in the mild to moderate range.  As to whether or not the diagnostic sleep study should have been done while your husband was on oxygen therapy, we try to complete sleep testing under baseline conditions whenever clinically appropriate.  It would appear from the pulse oximeter findings that your husband could do the study without supplemental oxygen that night but without reviewing a more thorough medical history and physical exam findings, I can't say with certainty that this is the case.  In any event, I infer from your comments that your husband is currently on oxygen therapy at night and that it has been determined to be sufficient to treat his present nocturnal oxygen desaturations.

Given your husband has demonstrated OSAS on his initial sleep study, a repeat sleep study with CPAP titration is indicated.  During that CPAP titration, it is expected that if your husband shows periods of oxygen desaturation not associated with obstructive events, he will most likely also be titrated on supplemental oxygen therapy to be given in line with the CPAP therapy.  This may sound complex but is not a big deal.  I say leave it to the specialists at the sleep lab to see to your husband's needs in this regard.

For now if your husband is on oxygen therapy and plans are underway to begin CPAP therapy for his OSAS, I feel he is on the right track.  If he has COPD, he has most likely been suffering from some degree of oxygen desaturation for years so several more weeks until CPAP is begun should not be of great concern.

Let me know if there is anything further I can do for you.

Sleep Apnea

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Dave Walsh RRT


Registered Respiratory Therapist and Licensed Respiratory Care Practitioner (IL). Thirty-five years in the field of Respiratory Care with the last twenty-five years spent concentrating in the area of sleep disordered breathing. Established the first hospital based compact multiphysiologic recording program for the diagnosis and treatment of obstructive sleep apnea syndrome (OSAS).


I'm proud to have built a comprehensive sleep disorders center in Chicago during the '80s and to then go on and build the first hospital based home sleep testing (HST) program in the country. I now own and operate Sleep Case Management, a Division of DRW&Associates Inc, providing sleep disorders case management services to physicians and their patients in northern IL along with providing home sleep testing and arrangements for in-lab sleep testing.

American Academy of Sleep Medicine, American Association for Respiratory Care

BSc (Biology), ASc (RT)

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