Objective
Nebulizers are widely used to treat diseases of the nasal cavity and paranasal sinuses, but contamination of drug solutions by reflux has recently become a concern. In this study we used to assess the usefulness of an anti-reflux valve, a safety device designed to prevent contamination of ultrasonic nebulizers. (1) scintigraphy and (2) bacterial cultures.
Methods
Round filters 5mm in diameter soaked in 370MBq technetium phytate were applied to the anterior ends of the bilateral inferior nasal conchae of 10 healthy adults, and the subjects were asked to inhale through an ultrasonic nebulizer (UN-703, Alfresa Pharma Corporation) for 3 minutes. Each subject inhaled through the nose for 2 seconds and exhaled through the mouth for 3 seconds, and the total expired gas was collected in an expiration bag (Xenon-133VSS). The experiment was divided into 2 parts: the 1st part was performed without the anti-reflex valve, the 2nd part was performed with the valve placed between the nasal tube and corrugated tube (flexible hose). (1) On scintiscanning, images were acquired with an ECOM (Toshiba Corporation) for a scintigraphy camera and a low-energy high-resolution parallel collimator. A Toshiba Nuclear Medical Data Processing Computer GMS7700 was used for analysis. Radioactivity in the face before inhalation and the face, nasal tube, anti-reflux valve, corrugated tube, residual solution in the medication cup, expiration bag, lung, and stomach after inhalation was counted. (2) Bacterial cultures were performed on swabs of the nasal cavity before using the nebulizer, and of the nasal tube, anti-reflux valve, corrugated tube, and residual solution in the medication cup after using the nebulizer.
Results
(1) When the anti-reflux valve was inserted, no reflux (RI accumulation) was noted in the corrugated tube or lower regions of nebulizer in any of the 10 subjects. Without the anti-reflux valve, reflux into the corrugated tube (RI accumulation) was noted in 6 of the 10 subjects. (2) When the anti-reflux valve was inserted, bacterial cultures of the corrugated tube and lower regions of nebulizer were negative in all 10 subjects. Without the anti-reflux valve, the corrugated tube or residual solution in the medication cup was positive in 4 of the 10 subjects, and reflux was detected by RI counts in all 4 of these subjects.
Discussion
Anti-reflux valves are useful in preventing reflux-induced contamination of drug solutions when ultrasonic nebulizers are used.
