Impact of initial flow rate of high-flow nasal cannula on clinical outcomes in infants with bronchiolitis.

AIM: Bronchiolitis is a common condition in the paediatric population. Severe cases often receive respiratory support with high-flow nasal cannula (HFNC). Significant variation in the application of HFNC exists throughout Australia and internationally. This study aimed to determine if the flow rate used initially and when ceasing HFNC at the end of the illness alters clinical outcomes. METHODS: A retrospective analysis was conducted of 251 children less than 12 months of age when admitted to the Women's and Children's Hospital Adelaide with bronchiolitis requiring HFNC therapy between the period of April 2016 to April 2019. The primary outcome was to determine if commencing HFNC therapy at different rates (1 L/kg/min, 1.5 L/kg/min and 2 L/kg/min) affected length of stay or treatment failure (escalation in physiological parameters or respiratory support). RESULTS: Treatment failure occurred in 33%, 13% and 26% of those starting at 1 L/kg/min, 1.5 L/kg/min and 2 L/kg/min, respectively. Commencing HFNC therapy at 1 L/kg/min increased length of stay by an average of 30 h (P < 0.001) and the likelihood of treatment failure (P < 0.002) compared with starting at 1.5 L/kg/min. There was no statistical difference in outcomes between starting at 1.5 L/kg/min and 2 L/kg/min. There was no significant difference in the length of stay from the starting of weaning HFNC to time of discharge. CONCLUSIONS: The commencing flow rates of initial HFNC therapy impact individual patient's outcomes, including length of stay and rates of treatment failure. Clinicians should consider commencing HFNC at 1.5 L/kg/min or 2 L/kg/min in infants that have failed low-flow oxygen therapy.

Effects of estradiol supplementation on the brain transcriptome of old rhesus macaques maintained on an obesogenic diet.

Obesity, the cessation of ovarian steroids with menopause, and age are risk factors for mood disorders, dementia, and Alzheimer's disease (AD). However, immediate hormone therapy (HT) after menopause may have beneficial effects in different brain regions involved in memory and cognition. To more closely replicate the age, endocrine, and metabolic environment of obese postmenopausal women, either on or off HT, middle-aged female rhesus macaques were ovariectomized/hysterectomized (OvH) and maintained on a high-fat, high-sugar, obesogenic Western-style diet (WSD) for 30 months; half of the animals received HT immediately after OvH and half served as placebo controls. RNAseq of the occipital (OC) and prefrontal cortex (PFC), hippocampus (HIP), and amygdala (AMG) identified 293, 379, 505, and 4993 differentially expressed genes (DEGs), respectively. Pathway enrichment analysis identified an activation of neuroinflammation in OC and HIP, but an inhibition in the AMG with HT. Synaptogenesis, circadian rhythm, mitochondrial dysfunction, mTOR, glutamate, serotonin, GABA, dopamine, epinephrine/norepinephrine, glucocorticoid receptor signaling, neuronal NOS, and amyloid processing were exclusively enriched in AMG. As compared to the placebo control group, most of these signaling pathways are downregulated after HT, suggesting a protective effect of HT in OvH females under a WSD. Overall, our results suggest that a chronic obesogenic diet may induce a wide range of alterations in multiple signaling pathways that are linked to age-associated brain pathology and dementia. In these individuals, HT seems to have a protective effect against neuroinflammation, amyloid beta depositions, and tau tangle formation.