Forced inspiratory nasal flow-volume curves: A simple test of nasal airflow

Objective: To observe and describe normal and abnormal inspiratory nasal fl ow-volume patterns. Patients and Methods: In this observational case series, individuals with a nd without nasal symptoms underwent forced inspiratory nasal flow-volume (F INFV) curve measurements. The participants were volunteer adults from the s taff and patients of a pulmonary subspecialty private practice office. To e xamine the flow patterns from the FINFV curves, definitions of normal and a bnormal were established. Normal curves were defined as those from particip ants who had no nasal symptoms and a peak inspiratory nasal flow greater th an 2.5 L/s. Abnormal curves were defined as those from participants who had 1 or more nasal symptoms, a peak inspiratory nasal flow lower than 2.5 L/s , and normal oral inspiratory flow. Results: Study participants consisted o f 10 staff and 58 patients. Fourteen individuals (21%) met the definition o f normal and had FINFV curves that mimicked the shapes of normal oral flow- volume curves; 39 (57%) met the definition of abnormal and had FINFV curves that mimicked the patterns of abnormal oral flow-volume curves. The abnorm al curves showed both fixed (33/39 [85%]) and variable (6/39 [15%]) pattern s of obstruction. Fifteen participants (22%) did not meet either establishe d definition. Conclusions: Forced inspiratory nasal flow-volume curves are a potentially useful clinical tool to measure nasal airflow. Normal and abnormal flow pat terns are easily identifiable.