Demographic and Clinical Characteristics
Children had a median age at culture collection of 2.8 years (IQR: 1.4-5.5, Table 1 ). Children were medically complex, with 30.7% having 7 or more CCCs. One quarter (26.1%) of children had comorbid BPD/CLDI. Two-thirds of cultures obtained (69.5%) were for children with current or previous chronic home ventilator use. Most cultures were obtained via sterile tracheal aspirate technique (61.4%) and collected during a hospital encounter (83.1%).
Cultures obtained with an accompanying ARI diagnosis were more frequent for children who were younger (2.3 years vs. 2.9 years, p<0.001), publicly insured (60.7% vs 53.5%, p<0.001), and without a diagnosis of BPD/CLDI (23.7% vs 27.0%, p<0.001) as compared with children with no ARI diagnosis (Table 1 ). Cultures obtained during ARI were also more frequent among children with 7+ CCCs (38.3% vs 28.0%, p<0.001). Differences in encounter and department at collection were observed, with cultures collected during ARI being less frequently obtained during an office visit, laboratory visit (i.e., specimen collection only visit), and in the bronchoscopy suite or post-anesthesia care unit (PACU). Cultures collected during ARI were much more frequently TA specimens (83.9%) versus BAL specimens, while cultures collected without ARI were only slightly more frequently TA specimens (53.6%, p<0.001, Table 1 ).
Most (77%) encounters with ARI diagnosis also met bARI diagnosis criteria (Table 1 ). Cultures obtained in children with bARI diagnosis were similar to those with ARI diagnosis, except that BPD/CLDI diagnosis was less frequent among with bARI (21.7%), PACU location was less frequent (1.6%), and TA specimen type was more frequent (90.2%,Table 1 ).