The peak flow nasal patency index.

The peak flow nasal patency index (NPI) is the ratio between the nasal and oral peak airflow. This index was found to be a good indicator of nasal patency present in 24 patients following septoplasty and indicated significant improvement postoperatively. The peak flow nasal patency index was also correlated to self-assessment scores of nasal function in each patient. In this latter study, a low index correlated to a high self-assessment score, both of which indicated poor nasal patency. Our studies have shown that the peak flow nasal patency index is a useful measure for determining nasal patency, particularly for defining the results of any applied therapies.