Breathing pattern and thoracoabdominal asynchrony in horses with chronic obstructive and inflammatory lung disease.

This research aimed to identify differences in breathing patterns between horses with healthy airways and horses with inflammatory airway disease (IAD) or recurrent airway obstruction (RAO). The study found that changes in thoracoabdominal asynchrony (TAA), in response to elevated CO2 levels, can serve as a useful marker for these conditions.

Research Methodology

• The study aimed to evaluate thoracoabdominal asynchrony (TAA), which quantifies the lack of synchronised movement between the thorax (upper body) and abdomen during respiration.
• This was done by comparing how the TAA changed between normal, calm breathing and hyperpnoea (a state of excessive breathing usually caused by hypoventilation or by exposure to excessive CO2), in healthy horses versus those diagnosed with recurrent airway obstruction (RAO) or inflammatory airway disease (IAD).
• The researchers used respiratory ultrasonic plethysmography (RUP), a non-invasive method of measuring respiration, to record the signals of the thoracic and abdominal movements.
• The synchrony between these two signals was quantified using Pearson’s correlation coefficient (PCC), which measures the degree of correlation between two variables. Here, the two variables were the movements of the horse’s thorax and abdomen during breathing. The quotient of the PCCs (PCCQ) during normal breathing and hyperpnoea was then calculated to express the changes in TAA.

Findings of the Research

• The researchers found that horses with RAO and IAD had significantly higher median PCCQ values compared to healthy horses.
• However, there was no statistically significant difference between the median PCCQ of horses with RAO and those with IAD, indicating that the degree of thoracoabdominal asynchrony was similar in both conditions.
• Horses diagnosed with a lung disorder displayed lower thoracoabdominal asynchrony compared to the healthy control group.

Conclusion of the Study

• This research provides insight into disease indicators in horses diagnosed with RAO and IAD. The findings highlight that TAA can serve as an effective parameter to differentiate these horses from healthy ones.
• Further, thoracoabdominal asynchrony could potentially be used as a non-invasive way to diagnose and monitor inflammatory airway disease and recurrent airway obstruction in horses.