Droplets Produced by Medical Nebulizers: Methods (Part 1)
The following products were assessed: Cadema nebulizer (Ca-dema Medical Products Inc., Middletown, NY) with compressed oxygen at 8 L/min; Up-Draft nebulizer (Hudson Up-Draft Oxygen Therapy Sales Co., Temecula, CA) with compressed oxygen at 8 U min; Up-Draft with Flatus Mk.V air compressor (Maymed, Anaesthetic Supplies Pty. Ltd, Sydney, Australia)—this system is equivalent to Tote-A-Neb, Hospitak Inc., Lindenhurst, NY (private communication, Laura Martinazzi); Up-Draft with Aerosol-One air compressor (Medical Industries America, Des Moines, I A); Mist-Oz-Gen ultrasonic nebulizer (Model EN143A, Timeter, PA).
These systems are representative of equipment used in the diagnosis of pulmonary embolism (Cadema nebulizer), non-isotonic challenge testing in asthma diagnosis (Mist-Oa-Gen) or for drug delivery in the treatment of various respiratory diseases (Up-Draft nebulizer, Up-Draft with Flatus Mk.V air compressor and Up-Draft with Aerosol-One air compressor). The flow rate produced by the Flatus Mk.V and the Aerosol-One air compressors through the UpDraft nebulizer containing 5 ml normal saline solution was found to be 6.3 and 5.0 L/min, respectively as measured by rotameter (Platon Ltd, Basingstoke, Harts, UK)
The change in temperature of each system was measured with an esophageal thermistor probe (YSI series 400, temperature recorder model 46TUC, Yellow Springs Instruments Co. Inc, Yellow Springs, OH) placed in the nebulizer solution, and the temperature was recorded at set times during aerosol generation until the temperature had reached a steady value (Ts). The initial volume of solution in the nebulizer was 5 ml (jet nebulizers) or 200 ml (ultrasonic nebulizer). The ambient temperatures varied between 23 and 24°C.