Reproducibility of airway responsiveness in horses using flowmetric plethysmography and histamine bronchoprovocation.
Authors: Nolen-Walston R D, Kuehn H, Boston R C, Mazan M R, Wilkins P A, Bruns S, Hoffman A M
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Flowmetric Plethysmography and Histamine Bronchoprovocation Reproducibility in Horses Inflammatory airway disease remains diagnostically challenging in equine practice despite its prevalence, making reliable measurement tools essential for consistent diagnosis and monitoring. Nolen-Walston and colleagues evaluated the reproducibility of flowmetric plethysmography with histamine bronchoprovocation (FP/HBP) testing across 29 healthy horses, measuring airway responsiveness via PC35 values (the histamine concentration required to increase airflow by 35%) at baseline, then again 1–4 weeks later and 3–12 months later. Short-term reproducibility was strong, with 85% of horses showing PC35 values within one doubling concentration of their baseline measurement (mean change 0.52 doubling concentrations), whilst long-term reproducibility remained acceptable at 73% within the same tolerance (mean change 0.81 doubling concentrations), with no significant difference between the two timeframes. These findings support FP/HBP as a reliable diagnostic and monitoring tool for assessing airway responsiveness over periods up to one year, though clinicians should account for potential measurement variation and note that ambient temperature conditions may influence results. The acceptable reproducibility validates this technique for tracking disease progression and treatment response in individual horses, provided practitioners maintain consistent testing conditions.
Read the full abstract on PubMed
Practical Takeaways
- •FP/HBP is a reliable diagnostic tool for assessing airway responsiveness in horses, with measurements remaining consistent enough for clinical decision-making over periods up to one year
- •When using PC35 as a diagnostic criterion, allow for variability of approximately ±1 doubling concentration between tests to avoid overinterpreting minor changes
- •Avoid testing horses during periods of extreme cold, as ambient air temperature appears to affect measurement reliability and comparability
Key Findings
- •85% of horses (23/27) had PC35 values within 1 doubling concentration at short-term retest (1-4 weeks), with mean change of 0.52 doubling concentrations
- •73% of horses (19/26) remained within 1 doubling concentration at long-term retest (3-12 months), with mean change of 0.81 doubling concentrations
- •No significant difference in reproducibility between short-term and long-term measurement periods
- •Flowmetric plethysmography with histamine bronchoprovocation shows acceptable reproducibility for airway responsiveness testing over up to 12 months, though ambient temperature effects warrant caution