[Sputum induction in children: Technical development]

Objective: To compare low and high flow nebulizers performance (total of samples) and its side effects on sputum induction in asthmatic children.

Patients and methods: Sputum induction was performed by inhalation of a hypertonic saline solution at increasing concentrations (3%, 4% and 5%) using low flow (OMRON NE-U07; flow rate 1ml/min), or high flow (OMRON NE-U12; flow rate 3ml/min, and DeVilbiss Ultraneb 3000; flow rate 2.5ml/min) ultrasonic nebulizers.

Results: We performed 49 inductions in 49 patients from 7 to 15 years old (in 15 children we used a low flow nebulizer (Omron NE-U07) and in 34 children a high flow nebulizer (OMRON NEU12, 6 patients, and DeVilbiss Ultraneb 3000, 28 patients). We obtained 37 samples of which 36 had less than 20% of squamous cells, and 26 had a viability > or =60%. The test performance was higher with high-flow nebulizers, obtaining 85.3% of samples compared to 53% (p=0.04). A total of 69% of samples obtained with the high flow nebulizer were valid, compared to 62.5% (p=0.7) with the low flow nebulizers. With high flow rate nebulizers the incidence of cough (17.6%, p=0.08) and itchy eyes (0%, p=0.02) decreased with the low flow nebulizer (47% and 20% respectively), but bad taste (82.3%, p <0.001) and salivation (14.7%, p=0.3) increased.

Conclusions: With high flow rate ultrasonic nebulizers we obtain a higher performance of the technique without an increase in significant side effects.