Development and clinical evaluation of a new sensor design for buccal pulse oximetry in horses.
Authors: Reiners J K, Rossdeutscher W, Hopster K, Kästner S B R
Journal: Equine veterinary journal
Summary
# Editorial Summary: Buccal Pulse Oximetry in Horses Conventional transmission pulse oximetry probes have proven unreliable in equine patients, limiting their clinical utility in monitoring oxygenation during anaesthesia and critical illness. Reiners and colleagues developed and tested a novel reflectance sensor design for placement on the buccal mucosa, integrating a standard Nonin 2000SL transmission probe into a new housing and evaluating three prototypes against arterial blood gas and invasive heart rate measurements in 13 anaesthetised horses during controlled desaturation (100–70% SpO₂). The most refined prototypes (N1 and N2b) achieved oxygen saturation accuracy comparable to the original sensor (root mean square deviation approximately 3.5%), though crucially this depended on obtaining reliable pulse signals—a limitation that becomes pronounced at heart rates ≤30 bpm, where readings were approximately double the actual rate. With these problematic measurements excluded, pulse rate accuracy matched the conventional sensor and Bland-Altman analysis showed acceptable limits of agreement. Whilst the buccal site offers practical advantages and SpO₂ accuracy appears promising when signal quality is adequate, clinicians should be aware that pulse rate readings require careful interpretation, particularly in bradycardic horses, and further refinement is needed before widespread clinical adoption. Future work validating performance in conscious horses and naturally occurring clinical scenarios will be essential for establishing this technology's reliability in practice.
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Practical Takeaways
- •A new buccal mucosa sensor design may offer a viable alternative to conventional transmission probes for monitoring oxygenation in anesthetized horses, addressing a significant limitation in equine anesthesia monitoring
- •Clinical validation in non-anesthetized and clinically diseased horses is still needed before adoption into general practice
- •Caution should be exercised with pulse rate readings at very low heart rates (≤30 bpm) as they may substantially overestimate the actual heart rate
Key Findings
- •New buccal reflectance pulse oximetry sensor achieved SpO2 accuracy comparable to conventional transmission sensors (Arms 3-3.6%) during desaturation protocols in anesthetized horses
- •Pulse frequency accuracy was problematic at heart rates ≤30 bpm with readings approximately twice the reference values
- •Bland-Altman analysis showed limits of agreement typical of clinical pulse oximeters when high-quality pulse signals were obtained
- •Pulse signal quality was the primary determinant of SpO2 reading accuracy