Respiratory-inductive-plethysmography-derived flow can be a useful clinical tool to detect patients with obstructive sleep apnea syndrome

Background/PurposeObstructive sleep apnea (OSA) is a common disorder characterized by recurrent episodes of a complete or partial collapse of the upper airway during sleep. The disease is traditionally diagnosed by overnight polysomnography with detection flow limitation by nasal pressure cannulas. The aim of this study was to evaluate the accuracy of flow (X flow) from calibrated respiratory inductive plethysmography.MethodsWe studied 60 male and 26 female patients who came to our sleep center in 2007. All the participants received overnight polysomnography and data were graded blindly and randomly by two experienced technicians.ResultsPatients with OSA were predominantly male, with higher body mass index, higher percentage of snorers, and more events of oxygen desaturation and arousal than those without OSA. There was a good correlation of X flow and flow from nasal pressure cannulas, regardless of total apnea–hypopnea, apnea or hypopnea events. The correlation was especially strong in severe OSA patients. The sensitivity and specificity to find OSA (apnea–hypopnea index ≥5) from X flow versus standard polysomnography was 98% and 100%, respectively. Positive predictive value was 100% and negative predictive value was 97%.ConclusionX flow could be a good clinical tool to be used instead of flow from nasal pressure cannulas in OSA patients.