This study group (Sleep Vol 32 No 7 p939-948) created a questionnaire that required only information about a person's gender, body-mass index, snoring history (yes or no) and blood pressure. From this information a score out of 18 was obtained. Scores above 11 were increasingly predictive of the presence of occult obstructive sleep apnoea.
Why did I like this paper?
Firstly, there was no question about sleepiness. Realising that people in the community who have obstructive sleep apnoea may be differentiated from those who go to the doctor with the problem by the absence of sleepiness, this somewhat-nebulous symptom was left out of the mix.
Secondly, a neat combination of two investigations that fall short of a full sleep study was used to evaluate for the presence of obstructive sleep apnoea. A home monitoring device was used which measured only the usual respiratory channels that we measure in the sleep lab - air pressure changes at the nose, thoracic and abdominal elasticated bands as well as pulse oximetery But how did they know when the person was asleep? A wrist actigraph was worn. This is essentially a motion sensor, the size of a wrist watch. When motion stops, sleep is assumed. This sort of device is used in evaluation of people with problems such as shift work sleep disorder, as it is more objective then a sleep diary. The combination of actigraphy and respiratory monitoring is much more simple then a full sleep study. Together they constitute, I think, reasonable way to follow up a community screening questionnaire. There will probably be more of this sort of diagnostic evaluation performed here once medicare agrees to pay for such a test.
Finally, I think we could use something like this here. It should not be difficult to validate for local conditions (our at-risk BMI is likely to be higher than the Japanese). And that has got me thinking ....
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