RESULTS: 170 NIV patients were compared to 128 non-NIV patients (57% of the cohort was treated with NIV during PICU stay). Median initial inspiratory (IPAP) and expiratory (EPAP) pressures were 12 and 6 cmH2O respectively, while median peak IPAP and EPAP were 14 and 8. Maximum IPAP used in any patient was 26 while the maximum EPAP was 12. Baseline characteristics were similar between groups except NIV patients had higher asthma score at ICU admission [median (IQR) 7 (5,8) vs 6 (5,7); p=0.0116]. The number of adjunctive medications patients received was comparable [median (IQR) 1 (1,1) for both groups]; however, patients on NIV were more likely to receive ketamine [21% vs 2%, p<0.0001], aminophylline [8% vs 1%, p=0.0056], and Heliox [7% vs 1%, p=0.0086]. A total of 8 patients were intubated (2.7%), but only 3 were intubated after first being treated with NIV (1.8% of those on NIV). Only two patients had barotrauma: 1 (0.6%) NIV patient and 1 (0.8%) non-NIV patient. NIV patients did have a longer ICU LOS than non-NIV patients even when adjusting for initial asthma score and other potential confounders (adjusted mean ICU LOS 2.68 vs 1.74 days; p<0.0001). The strongest association with longer LOS was seen with invasive mechanical ventilation [risk ratio 2.63 (1.87, 3.71); p<0.0001].