The Effects of Noncontinuous Positive Airway Pressure Therapies on the Aerodynamic Characteristics of the Upper Airway of Obstructive Sleep Apnea Patients: A Systematic Review

Abstract

The effects of noncontinuous positive airway pressure (non-CPAP) therapies on the airflow in the upper airway in obstructive sleep apnea (OSA) patients are not completely clear yet. Therefore, the primary aim of this systematic review was to determine the effects of various non-CPAP therapies on the aerodynamic characteristics of the upper airway in OSA patients. A PICO (population or patient, intervention, comparison, outcome) search strategy, focusing on the effects of various non-CPAP therapies on the aerodynamic characteristics of the upper airway (ie, velocity, wall shear stress, wall static pressure, airway resistance, pressure drop, and pressure effort) of OSA patients, was conducted in the following databases: MEDLINE (PubMed), Embase (Excerpta Medica), and Web of Science. In this systematic review, the inclusion criteria were 1) adults diagnosed with OSA by polysomnography, 2) treatment outcome assessed by a second polysomnography, and 3) computational fluid dynamics (CFD) applied. Of 51 unique studies retrieved, 9 fulfilled the criteria for this systematic review. Seven studies were on maxillomandibular advancement (MMA) surgery, and 2 were on mandibular advancement device (MAD) therapy. The aerodynamic characteristics of the upper airway improved in OSA patients who underwent MMA surgery. However, the studies on MMA surgery included only responders to MMA surgery. In the responders to MAD therapy, the velocity, wall static pressure, and airway resistance of the upper airway decreased. In nonresponders to MAD therapy, the wall static pressure and airway resistance of the upper airway increased. This systematic review suggests that MMA surgery and MAD therapy may improve several aerodynamic characteristics of the upper airway in OSA patients by CFD analysis. However, because of limitations of the selected studies, there is not enough evidence yet to support CFD analysis as a routine tool to predict the treatment outcome in OSA patients.