Comparative Evaluation of Apnoea Graph and Polysomnography in Sleep Disordered Breathing in an Urban Indian Population

Apnoea graph (AG) system is a new technology designed for evaluation of Sleep Disordered Breathing and more importantly the site of obstruction in Obstructive Sleep Apnoea (OSA). Apnoea Graph being a new modality of assessment needs to be evaluated with the time tested gold standard PolySomnoGraphy (PSG) along with its unique capability of establishing the level of obstruction. A prospective study of 30 patients of snoring and/or suspected for OSA was conducted in Sir Ganga Ram Hospital, New Delhi with recordings of both overnight sleep study and apnoea graph performed separately for each patient. The respiratory parameters of AG were compared with PSG. The percentage (%) of levels of obstruction identified by apnoea graph was calculated. We found that apnoea graph system was capable of diagnosing OSA and could also grade its severity. On comparing this new tool with PSG, we could deduce that there was comparability between the two tests with respect to pulse oximetry parameters with limitations with respect to Apnoea/ Hypopnoea Index (AHI) levels. The advantages and limitations of apnoea graph are highlighted. We conclude that Apnoea Graph is an innovative tool having the ability to diagnose the site of airway resistance and proves to be a valuable guide to the surgeon to select the most appropriate treatment in OSA.