Evaluation of Nasal Oxygen Administration at Various Flow Rates and Concentrations in Conscious, Standing Adult Horses.
Authors: Gordon Danielle, Clark-Price Stuart, Keating Stephanie, Schaeffer David J, Lascola Kara M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Nasal Oxygen Delivery in Standing Horses Supplemental oxygen therapy is routinely used in equine practice, yet optimal delivery parameters for conscious, standing horses remain poorly characterised. This investigation examined how different combinations of flow rate (5, 15, or 30 L/min) and oxygen concentration (21%, 50%, or 100%) affected arterial oxygenation and the actual fraction of inspired oxygen reaching the distal trachea in six healthy adult horses via single nasal cannula. Both increasing flow rate and oxygen concentration significantly elevated blood oxygen levels (PaO2), though the inspired oxygen concentration measured at the trachea fell consistently short of the concentration measured at the nares—a dilution effect particularly pronounced at higher oxygen fractions. Notably, 50% oxygen at 15–30 L/min produced equivalent or superior tracheal oxygen delivery compared to 100% oxygen at lower flow rates, all whilst maintaining normal ventilation and acid–base status without adverse effects. For practitioners managing hypoxaemic horses, these findings suggest that 50% oxygen delivered at moderate flow rates offers an efficient, well-tolerated approach that avoids the potential complications of higher concentrations whilst still achieving clinically meaningful oxygenation improvements; however, the authors appropriately flag that further evaluation in horses with actual respiratory pathology is needed before definitive clinical protocols can be established.
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Practical Takeaways
- •50% oxygen delivered via nasal cannula at 15–30 L/min effectively raises arterial oxygen in conscious standing horses and is well tolerated—consider this as a practical in-field option before progressing to higher concentrations or flow rates
- •Expect lower oxygen delivery to the distal trachea than what you measure at the nares; account for this dilution when titrating therapy in hypoxemic patients
- •This technique produces no respiratory depression or CO2 retention, making it suitable for conscious patients requiring sustained oxygen support without sedation
Key Findings
- •FIO2 and PaO2 increased significantly with increasing flow rate and oxygen fraction (P < 0.0001), with no adverse reactions observed at any flow rate tested
- •Tracheal FIO2 was significantly lower than nasal FIO2 at 50% and 100% oxygen across all flow rates (P < 0.0001), indicating gas mixing loss distally
- •50% oxygen at 15–30 L/min produced comparable or superior PaO2 increases to 100% oxygen at lower flow rates, suggesting therapeutic efficiency
- •Respiratory rate, ETCO2, PaCO2, and pH remained unchanged across all treatments, indicating nasal cannula oxygen administration does not affect ventilation parameters