Alternatives to the standard method of diagnosing sleep apnea (SA) are
becoming increasingly popular due to the expense and/or, in some case
s, the limited availability of polysomnography (PSG). The most common
diagnostic alternatives have been clinical prediction rules and portab
le monitoring. Most portable monitors record one or more signals such
as oxygen saturation, heart rate, airflow, or ribcage and abdominal mo
vements. To date, most published studies of these monitors have had se
rious methodologic problems that have limited the acceptance of this t
echnology. We have developed a two-step diagnostic approach for SA bas
ed on a clinical prediction rule and the results from a simple, but re
liable and accurate, portable monitor that records oxygen saturation,
snoring, and body position. The preliminary results indicate that such
a strategy is very useful in a population of outpatients suspected of
having SA and would preclude the need for PSG to investigate for this
possibility in the majority of patients. However, before portable mon
itoring becomes widely adopted, each system should be more thoroughly
tested, and increased attention should be directed at the design of th
e study so that the results are more generalizeable to other sleep cli
nic populations.