A simplified pneumotachometer for the quantitative assessment of velopharyngeal incompetence

By applying pipe flow rate mechanics, the authors have developed a simple and inexpensive device that can measure oral and nasal airflow and pressure quantitatively. It allows clinicians to document objectively the degree of velopharyngeal incompetence and nasal airway obstruction. This device is a modified U-manometer with a Y-connector to a collection bag. This prototype is being used in the authors' cleft palate clinic and they have found it useful in documenting quantitatively the amount of nasal air escape from either nostril with the corresponding pressure and flow. The primary measurement, which is reproducible and reliable, is the product of a cross-sectional area of oronasal communication and the pressure differential between the oral and nasal cavity. With some modifications, this device can be adapted to estimate the size of the oronasal communication.