Thursday, August 22, 2013

Sleep Study Redux

Got the results back from my sleep study and all I can say is that I'm pretty darn confused:

Clinical Background:
34 year-old patient is now referred for an unattended diagnostic
sleep recording.

An ambulatory PSG with a digital sleep system for recording
respiratory effort, oximetry, body position, airflow, pulse rate,
and limb movement channels.

Total recording time was 253.1 minutes. The patient estimated a
total sleep time of 178.0 minutes. 

Respiratory Analysis demonstrated 5 obstructive apneas and 12
hypopneas, with an APNEA HYPOPNEA INDEX (AHI) of 5.7. The
patient spent 0.0% of total sleep time in the supine position,
with a supine AHI of 0.0, versus a non-supine AHI of 5.7, though
the body position cannot be verified. 

The lowest oxygen saturation was 89 %, and 0.0 % of the sleep
time was spent at saturations below 90 %.

The pulse rate was at 78 beats per minute.

The PLM Index was 50.9 events per hour. 

1. Sleep study findings are consistent with mild Obstructive
Sleep Apnea. The overall RDI was 5.7 events per hour of sleep. 
The lowest oxygen saturation was 89 %. This unattended study
likely under estimates the severity of the patient's sleep apnea
(as measured by the AHI) as frequent periods of flow limitation
in addition to the scored events were observed, but these could
not be scored as respiratory events due to lack of EEG channels
in this limited channel unattended sleep study.
2. Evidence of snoring was present.
3. There is also evidence of frequent periodic limb movements. 
Due to lack of EEG channels in this limited channel unattended
sleep study it cannot be determined whether these leg movements
were present during sleep and if they are associated with
significant cortical arousals and sleep fragmentation. 
4. Positive airway pressure therapy (CPAP) is usually the most
effective treatment option. Surgical treatment modalities are
alternative options. An oral appliance may be effective
treatment in mild cases. The patient should avoid sleeping in
supine position (i.e. side-sleeping or elevation of the head 30
degrees is preferred). Other non-specific adjunctive treatment
include significant weight loss, and avoidance of sleep
deprivation, alcohol and nicotine. 
5. It is recommended that the patient come-in to the sleep lab
for a full-night attended polysomnographic titration sleep study
to determine the optimal positive airway pressure therapy and
this attended sleep study recording is indicated for further
evaluation of periodic limb movements as well. He will be called
to schedule this study. 

Sleep study raw data was manually reviewed and the report
reviewed, edited, and electronically signed by me. Please feel
free to contact me if you have any questions.

I reported on the form exactly what I wrote in my previous blog entry. I'll reproduce the focus of my confusion:

I doubt there will be anything useful in the hour or less of sleep data that got recorded. I am unlikely to try this again.

I'm not confused about how much sleep I got during the study. I was very careful to write it down. I got less than 60 minutes of sleep. While that may not be entirely precise, I can guarantee I didn't get three hours of sleep. So I apparently have apnea events that I don't notice while I'm awake. I think I can explain the restless limb movements; I was using my limbs.

I am now more turned off toward this.

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