Flow interruption compared to forced oscillatory maneuvers and esophageal balloon/pneumotachography for measurement of respiratory resistance in the horse.

This research looked at ways to test the lung function in horses with asthma, specifically comparing the effectiveness of a new, non-invasive technique called flow interruption (FI) with the traditional, more complex methods of forced oscillatory mechanics (FOM) and esophageal balloon/pneumotachography (EBP). The study concluded that the FI method correlates well with the traditional approaches and could be a more accessible and straightforward option.

Objective and Methodology

• The researchers aimed to investigate a simpler, non-invasive alternative method for testing pulmonary function in horses, vital for diagnosing equine asthma. This condition represents a significant strain of respiratory diseases in horses, but its clinical diagnosis has been limited due to the complicated traditional methods (EBP and FOM).
• The alternative method they proposed is called flow interruption (FI), which involves a rapid halt of airflow, allowing the alveolar pressure to balance with proximal airway pressure.
• The idea is to compute the resistance (R) as the relationship between the difference in pressure at the nose before and after the interruption, and flow immediately ahead of interruption.

Pilot Study and Further Testing

• The researchers first conducted a pilot study using both EBP and FI on 5 healthy horses owned by a university and found a good correspondence between the two methods.
• They extended their study to two other groups of client-owned horses. In one group, FI and EBP were randomly assigned (n = 8), and the results showed a good correlation.
• In the second group, the horses were tested using FOM (n = 12). Again, the FI results correlated well, although they were consistently smaller than those obtained with FOM.

Results and Conclusion

• The research showed that the newly proposed technique (FI) was effective and comparable to the traditional methods of EBP and FOM in terms of accuracy and reliability.
• However, it is worth noting that when Histamine bronchoprovocation (HBP) was performed on a subset of the horses, FI classified a few horses as less reactive than did EBP and FOM.
• Overall, the study provides valuable insights into a potential alternative for diagnosing equine asthma by means of the flow interruption method, which is less invasive and more straightforward than the standard, more complex ways of testing.