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Airway inflammation is highly prevalent in horses, with the majority of non-infectious cases being defined as equine asthma. Currently, cytological analysis of airway derived samples is the principal method of assessing lower airway inflammation. Samples can be obtained by tracheal wash (TW) or by lavage of the lower respiratory tract (bronchoalveolar lavage (BAL) fluid; BALF). Although BALF cytology carries significant diagnostic advantages over TW cytology for the diagnosis of equine asthma, sample acquisition is invasive, making it prohibitive for routine and sequential screening of airway health. However, recent technological advances in sample collection and processing have made it possible to determine whether a wider range of analyses might be applied to TW samples. Considering that TW samples are relatively simple to collect, minimally invasive and readily available in the horse, it was considered appropriate to investigate whether, equine tracheal secretions represent a rich source of cells and both transcriptomic and proteomic data. Similar approaches have already been applied to a comparable sample set in humans; namely, induced sputum. Sputum represents a readily available source of airway biofluids enriched in proteins, changes in the expression of which may reveal novel mechanisms in the pathogenesis of respiratory diseases, such as asthma and chronic obstructive pulmonary disease. The aim of this study was to establish a robust protocol to isolate macrophages, protein and RNA for molecular characterization of TW samples and demonstrate the applicability of sample handling to rodent and human pediatric bronchoalveolar lavage fluid isolates. TW samples provided a good quality and yield of both RNA and protein for downstream transcriptomic/proteomic analyses. The sample handling methodologies were successfully applicable to BALF for rodent and human research. TW samples represent a rich source of airway cells, and molecular analysis to facilitate and study airway inflammation, based on both transcriptomic and proteomic analysis. This study provides a necessary methodological platform for future transcriptomic and/or proteomic studies on equine lower respiratory tract secretions and BALF samples from humans and mice.

Airway inflammation is highly prevalent in horses, with the majority of non-infectious cases being defined as equine asthma. Currently, cytological analysis of airway derived samples is the principal method of assessing lower airway inflammation. Samples can be obtained by tracheal wash (TW) or by lavage of the lower respiratory tract (bronchoalveolar lavage fluid; BALF). Although BALF cytology carries significant diagnostic advantages over TW cytology, sample acquisition is invasive, making it prohibitive for routine and sequential-screening of airway health. The aim of this study was to establish a robust protocol to isolate macrophages, protein and RNA for molecular characterisation of TW samples and demonstrate the applicability of sample handling to rodent and human pediatric bronchoalveolar lavage fluid isolates. TW samples provided a good quality and yield of both RNA and protein for downstream transcriptomic/proteomic analyses. The sample handling methodologies were successfully applicable to BALF for rodent and human research. TW samples represent a rich source of airway cells, and molecular analysis to facilitate and study airway inflammation, based on both transcriptomic and proteomic analysis. This study provides a necessary methodological platform for future transcriptomic and/or proteomic studies on equine lower respiratory tract secretions and BALF samples from humans and mice.

Aims Assessing the potential effect of three discharge oxygen saturation (SpO2) targets ( 90%, 94% and 94%) on length of hospital admission in children with wheeze. Methods and patients: Children (1 16 years (y)) admitted with wheeze and oxygen requirement for SpO2 (£92%), had SpO2 in air assessed 4 hourly. Time from admission for SpO2 to become stable for at least 4 hours (h) at 90%, 92% and 94% was recorded. Results 243 children were admitted with wheeze (n=14 excluded due to inadequate demographic data or observation). Fourty eight children did not require oxygen and 39 children reached discharge criteria prior to the specified time ( 4 hour) at SpO2 targets. The median time to discharge was 23 hour (IQR 17 39) for all children admitted with wheeze (n=229), 27 hour (17 40) for children requiring supplemental oxygen (n=181) and 30 hour (IQR 17 40) for children requiring oxygen supplementation and a full data set (n=142). Data on the latter patients (median age 2.8y) were further assessed. Five children were admitted to high dependency. Seventy percent (99/142) had a viral or bacterial agent identified. Time from admission to a stable SpO2 for 4 hour was 8 hour (IQR 5 20) for SpO2 90% in air, 17 hour (IQR 7 30) for SpO2 target of 92%, and 21 hour (IQR 21 30) for SpO2 target of 94%. A time lag was observed in 61 (43%) children between SpO2 targets of 90% and 92% and in 75 (53%) children between targets of 90% and 94%. Presence of any infective agent was not associated with time to stable oxygen at any threshold, except for RSV. RSV was statistically significantly (p Conclusions Reducing SpO2 target levels to 90% in children with acute wheeze could potentially reduce length of stay. This target level has been shown to be safe in infants with bronchiolitis, while it can be postulated that the same would be true for older children with wheeze, a randomised control trial to assess the safety and effect on clinical status is warranted.