Response to nasopharyngeal oxygen administration in horses with lung disease.
Authors: Wilson D V, Schott H C, Robinson N E, Berney C E, Eberhart S W
Journal: Equine veterinary journal
Summary
# Editorial Summary: Nasopharyngeal Oxygen Administration in Equine Respiratory Disease Until recently, evidence-based guidelines for oxygen therapy in standing horses remained lacking, partly because earlier work produced inconsistent results regarding whether nasal oxygen delivery actually improved arterial oxygenation. Wilson and colleagues addressed this gap by administering oxygen at graduated flow rates (5–30 L/min) via nasal cannulae to six healthy horses and six animals experiencing acute recurrent airway obstruction (RAO), measuring both inspired oxygen concentration and arterial blood gas tensions throughout. Whilst all horses tolerated flow rates up to 20 L/min, nasal supplementation significantly increased arterial oxygen tension (PaO2) in both groups—though horses with RAO showed consistently lower values at every flow rate, reaching 264 ± 69 mmHg at maximum flow compared to 319 ± 31 mmHg in controls. Notably, RAO-affected animals demonstrated markedly increased alveolar dead space ventilation, explaining their blunted oxygen response despite improved inspired oxygen fractions. For practitioners managing horses with respiratory compromise, these findings provide practical dosing recommendations: 10–20 L/min via single cannulae represents an effective starting point, with dual cannulae deployment reserved for situations requiring higher flow rates, though clinicians should monitor closely for coughing or gagging at maximum flows.
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Practical Takeaways
- •Intranasal oxygen therapy is effective for improving blood oxygenation in horses with respiratory disease; use 10-20 l/min flows for best tolerance
- •Horses with RAO show lower oxygen uptake than healthy horses at equivalent delivery rates, so higher flows or dual cannulae may be needed therapeutically
- •Avoid 30 l/min single-cannula delivery due to adverse respiratory responses; use two cannulae if higher flow rates are clinically necessary
Key Findings
- •Nasal cannula oxygen administration significantly increased arterial oxygen tension (PaO2) at all flow rates in both control and RAO-affected horses (P < 0.001)
- •At 30 l/min flow, PaO2 reached 319 ± 31 mmHg in control horses and 264 ± 69 mmHg in RAO-affected horses
- •Fractional inspired oxygen concentration (FiO2) increased with flow rate but was significantly lower in RAO horses compared to controls at all rates
- •Oxygen flow rates up to 20 l/min were well tolerated; 30 l/min produced occasional coughing or gagging in horses