Backgrounds and aims Wood Downes’s modified by Ferres score (WDF) was not designed for the bronchiolitis, but its use has been generalised to evaluate the severity. Our aim is to relate the length of stay and the bronchiolitis´s severity at admission, by WDF.

Patient and methods We included the acute bronchiolitis hospitalised during two epidemics (2011–2013). They were classified in mild (MiB; WDF <4), moderated (MB; WDF 4–7) or severe (SB; WDF > 7) according to the scale WDF realised at admission. The mild ones and to the patients without WDF at admission were excluded. The main variable was the length of stay. We registered: age, RSV, sex, previous and during treatment and UCIP’s need. Analysis with SPSS 17.0.

Results 208 hospitalised infants were included (mean age of 72,9 days (5–373). Positive RSV in 67,8%. 90,5% were MB and 9,5% SB. Both groups were homogeneous in demographics data and previous admission treatment (p > 0.05). The mean WDF at admission was 5,42 (4–10). During the hospitalisation, they received nebulised bronchodilator in 3% hypertonic saline solution (3%SSH) (65%) or 3%SSH (35%). 22% received corticoids and 8,2% antibiotics. Length of stay: 5,3 days (0–46). The MB had an mean length of stay of 4,8 days and the SB of 13,44 (p = 0.0001).

Conclusions WDF’s scale has demonstrated, in our sample, to be a good predictor of the length of stay in moderate and severe bronchiolitis. The SB had a statistically significant more length of stay than MB.