Abstract
BACKGROUND:
Respiratory inductance plethysmography (RIP) is a tool used during a polysomnogram (PSG), which serves as a surrogate of respiratory effort and can help detect inspiratory air-flow limitation. We hypothesize that RIP can improve the sensitivity and specificity of scoring hypopneas when compared with both the recommended and acceptable criteria of the American Academy of Sleep Medicine.
METHODS:
We retrospectively analyzed a cohort of 12 subjects who had no obstructive sleep apnea (OSA) or mild OSA on PSG when scored by the American Academy of Sleep Medicine acceptable criteria for hypopneas but had high clinical suspicion for a diagnosis of OSA. These subjects were rescored using the American Academy of Sleep Medicine recommended criteria as well as RIP. Hypopnea was scored when there was a 50% decrease in the amplitude of the RIP sum channel (which combined input from chest and abdominal belts). OSA was diagnosed if the subjects had >5 respiratory events/h of sleep. The subject's response to CPAP was assessed by using a short questionnaire called the post-PSG sleep assessment. which evaluated subjective sleep quality. A positive response was considered an improvement in the post-PSG sleep assessment score after CPAP use.
RESULTS:
When scored using the American Academy of Sleep Medicine acceptable criteria, 10 subjects had a negative study, and 2 subjects had mild OSA for a sensitivity of 11% and specificity of 50%. When scored using the recommended criteria, 10 subjects had OSA, and 2 were negative, for a sensitivity of 78% and specificity of 70%. By RIP scoring, all 12 subjects had >5 respiratory events/h for a sensitivity of 100% and specificity of 75%.
CONCLUSIONS:
This small retrospective pilot study showed improved sensitivity and specificity when scoring hypopneas by RIP sum channel.
Get full access to this article
View all access options for this article.