Aim Characteristics of children with bronchiolitis requiring PICU, causative organisms, PICU length of stay and outcome.

Methods Case control study of all patients <2 years who were admitted with bronchiolitis (SIGN guidelines) between 01/2014– 05/2016 to a tertiary level PICU.

Results 80 children were admitted with the following demographics: Median age 2 months, IQR: 4.5 months. 59/80 (74%) admissions matched seasonal distribution (November–March). 37/80 (46%) patients had comorbidities (prematurity, cardiac, immunodeficiency). Level of respiratory support: non-invasive ventilation: 5% (4/80), conventional ventilation: 72.5% (58/80), high frequency oscillation ventilation (HFOV): 21% (17/80) and one ECMO case. Comorbidity was a risk factor for HFOV in 65% (11/17). Indication for intubation was: apnoea 27/76 (36%), respiratory acidosis 49/76 (64%). Nasopharyngeal aspirate (NPA) was positive in 64/80: 31 RSV A, 14 RSV B, 8 Parainfluenza, 3 Rhinovirus, 3 CMV, 2 Metapneumovirus, 2 Adenovirus, and 1 Influenza A.

Total RSV positive NPA: 45/80 (56%). 6/31 RSV A positive patients had non-typeable Haemophilus Influenzae (NTHi) with sightly longer median ventilation days (5.5 vs 4 days). RSV infection accounted for majority of HFOV children 59% (10/17), and was responsible for 59.3% (16/27) intubation for apnoea, 59.2% (29/49) for respiratory acidosis. Comorbidities group had longer ventilation days and PICU length of stay compared with patients with no associated morbidities (6 days vs 4 days, p<0.16), and (10 days vs 5 days, p<0.006) respectively. Post extubation: 20/35 patients with comorbidities required high level of O2 support (NIV, HFNC) compared with 12/41 patients without comorbidities (57% vs 29%, OR:3.04). Mortality was significant in the comorbidities cohort (2 preterm, 2 immunocompromised) compared with none in the group with no comorbidities (11% vs 0%).

Conclusions Bronchiolitis remains a common cause for seasonal admission to PICU with significant length of stay, morbidity, and mortality for those with comorbidities. Concern about its associated cost is still a major challenge. Respiratory acidosis was twice as common cause for intubation. RSV was the most common encountered pathogen (56%) despite palivizumab introduction in 2010. We noticed unclear association of NTHi with RSV A infection. It is interesting to review preterm children who had palivizumab to see if they are underrepresented in PICU and consider its use in immunocompromised children as they have a high mortality.