OK, maybe that wouldn't be such a good method.
You could also throw in there whether or not you're using Medicare criteria, which insists on having a desat in order to label a hypopnea as such. That could really mess us some peoples' AHI. By their rules, you would then call airflow reductions of >30% without an associated desaturation of at least 4% a RERA (Respiratory Effort-Related Arousal) and include it in the RDI (Respiratory Disturbance Index) as opposed to the AHI.
Speaking of which, the acceptance of the definition of mild is also probably pushed by Medicare, who will authorize the use of CPAP at AHI 5-14 when additional symptoms are documented, like excessive daytime sleepiness, impaired cognition, mood disorders or insomnia, hypertension, ischemic heart disease or history of stroke.
If you were going to use a one-word summary to define the severity of OSA, this guy's hybrid isn't too bad, including AHI (however you want to define it), oxygen desaturation nadir and sleepiness:
SAGwhat'shisface wrote: Mild: An apnea-hypopnea index from 5 to 14. An oxygen saturation of at least 86%. Unwanted sleepiness or involuntary sleep episodes occur during activities that require little attention. Examples include sleepiness that is likely to occur while watching television, reading, or traveling as a passenger. Symptoms produce only minor impairment of social or occupational function.
Moderate: An index from 15 to 30. An oxygen saturation of 80% to 85%. Unwanted sleepiness or involuntary sleep episodes occur during activities that require some attention. Examples include uncontrollable sleepiness that is likely to occur while attending activities such as concerts, meetings or presentations. Symptoms produce moderate impairment of social or occupational function.
Severe: An index greater than 30. An oxygen saturation of 79% or less. Unwanted sleepiness or involuntary sleep episodes occur during activities that require more active attention. Examples include uncontrollable sleepiness while eating, during conversation, walking, or driving. Symptoms produce marked impairment in social or occupational function.
AHI and EDS references from:
Flemons WW. Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. Sleep 1999;22(5):667-89.
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CPAPopedia Keywords Contained In This Post (Click For Definition): medicare, Arousal, CPAP, AHI, RDI, Hypopnea
