Thoracoabdominal asynchrony failed to grade airway obstructions in foals.

This research aimed to understand if respiratory inductive plethysmography (RIP), a device to measure tidal volume, can accurately assess the degree of airway obstruction in foals based on thoracoabdominal asynchrony. The study found that although RIP variables did change significantly with obstruction, they were erratic and therefore not useful for accurately grading these obstructions.

Respiratory Inductive Plethysmography (RIP)

• RIP is a device that measures tidal volume, or the amount of air that moves in or out of the lungs during a single breath.
• It can also assess the relative contributions of the thorax and abdomen to ventilation.

Thoracoabdominal Asynchrony and Airway Obstruction

• Thoracoabdominal asynchrony, a discordance between the movement of the chest and abdomen during breathing, is a common symptom in patients with airway obstruction.
• However, the accuracy of using RIP to assess the severity of this obstruction based on thoracoabdominal asynchrony is uncertain.

Study Methodology

• Eight foals were used in the study as this species and age group are commonly afflicted with respiratory disease.
• These foals, under sedation, were subjected to randomly ordered resistive loads at the airway opening. On a separate day, they were also exposed to a histamine aerosol challenge.

Study Findings

• In the face of resistive loading, the phase angle and phase relation, characteristics of respiratory asynchrony, showed significant changes. However, the degree of these changes was found to be erratic and did not correlate consistently with the degree of change in the resistive load.
• Moreover, neither phase angle nor relation changed significantly with histamine challenge.
• The study concluded that although RIP could detect some changes associated with airway obstruction, the erratic nature of these changes rendered them inefficient as measurement tools for grading the severity of these obstructions.
• Additionally, RIP variables did not react significantly to histamine-induced bronchoconstriction, indicating their insensitivity to certain types of airway obstruction.