Effects of nasal cavity ventilation expansion techniques on airlfow patterns of the upper airway / 中国耳鼻咽喉头颈外科

ABSTRACT

[ABSTRACT]OBJECTIVETo compare the aerodynamic differences before and after nasal cavity ventilation expansion techniques in patients with OSAHS. METHODSA total of 30 adult patients with OSAHS were included in this study. Pre-operative upper airway CT of each subject was acquired. Each subject underwent surgery. Postoperative upper airway CT was obtained at least 3 months later. By means of CFD simulation method, numerical simulation was performed to calculate the airflow dynamic indexes of the upper airway. The pre-and post-operative aerodynamic characteristics were compared. RESULTSAfter operation, post-operative negative pressure nephogram of the nasal cavity indicated more smooth variation of pressure gradient, post-operative velocity nephogram of nasal cavity indicated slower airflow velocity. Proper values of flow field indicated the volume of nasal cavity increased significantly (t=4.025,P<0.01), the total nasal airway resistance decreased significantly (t=-2.065,P<0.01). The total negative pressure of the upper airway decreased significantly (t=-2.659,P<0.01) after operation. However, the proper values of flow field increased in 5 patients. CONCLUSIONNasal cavity ventilation expansion effectively increase the volumes of nasal cavity, improve the nasal ventilation, and reduce the air flow velocity of both nasal cavity and pharynx in OSAHS patients, those reduce the pharyngeal negative pressure and the pharyngeal collapse. However, for patients with its narrowest segment at the velopharyngeal level, operation cannot do anything or even aggravate the pharyngeal collapse. Operation should be performed individually.