Objective diagnosis of alar fold collapse in active Standardbred trotting racehorses using nasopharyngeal airway pressure measurements.
Authors: Strand Eric, Vermedal Hanna, Olsen Hanna Margrethe Berg, Fjordbakk Cathrine Taule, Fretheim-Kelly Zoe Louise
Journal: Equine veterinary journal
Summary
# Editorial Summary: Objective Assessment of Alar Fold Collapse in Racing Standardbreds Currently, veterinary diagnosis of alar fold collapse relies on subjective observations of breathing improvement following temporary or permanent surgical correction—an approach that lacks precision and makes it difficult to quantify the severity of airway obstruction or objectively measure treatment success. Norwegian researchers addressed this gap by using nasopharyngeal airway pressure (NAP) measurements to objectively assess alar fold collapse in 21 actively racing Standardbreds, measuring peak inspiratory and expiratory pressures before and after temporary dorsal suturing of the alar folds, with post-operative measurements obtained in 13 horses. The key finding was that expiratory NAP decreased significantly (p <0.001) from a baseline mean of 35.8 cmH₂O to 20.1 cmH₂O following temporary suturing, and further to 13.3 cmH₂O after complete surgical resection, whereas inspiratory pressures showed no significant change—indicating that alar fold collapse creates a moderate to marked obstructive effect specifically during the exhalation phase of exercise. For equine practitioners, these results offer a quantifiable diagnostic tool that could standardise clinical decision-making around whether alar fold surgery is warranted and provide objective evidence of surgical efficacy, moving beyond the current reliance on owner-reported improvements in respiratory noise or subjective assessments of breathing ease.
Read the full abstract on PubMed
Practical Takeaways
- •NAP measurement during treadmill exercise at heart rate ≥200 bpm offers an objective diagnostic tool to confirm suspected alar fold collapse, moving away from subjective clinical assessment of breathing improvement
- •Expiratory pressure measurements are more diagnostically useful than inspiratory measurements for detecting alar fold collapse, suggesting the obstruction is primarily expiratory in nature
- •Post-operative NAP monitoring can precisely quantify surgical success and guide treatment decisions for horses with suspected alar fold collapse affecting racing performance
Key Findings
- •Nasopharyngeal airway pressure (NAP) measurements provide an objective method to diagnose alar fold collapse during exercise in Standardbred trotters
- •Temporary dorsal suturing of alar folds significantly reduced expiratory NAP from 35.8±8.81 cmH2O to 20.1±7.04 cmH2O (p<0.001), but did not affect inspiratory NAP
- •Complete surgical resection of alar folds further reduced expiratory NAP to 13.3±2.29 cmH2O in 13 horses available for post-operative testing
- •Alar fold collapse caused moderate to marked expiratory airway obstruction in many affected racing horses