CONTINUOUS MEASURES OF BREATHING AND PHASE ANGLE IN CONSCIOUS CYNOMOLGUS MONKEYS

Abstract

We evaluated an inductance plethysmography (IP) system in 3 allergic cynomolgus monkeys for measurement of breathing and phase angle (Φ) as a surrogate for airway resistance. Initial studies in anesthetized, intubated animals compared a standard pneumotachograph measure of ventilation with IP to estimate the accuracy of the measurement. Data showed excellent agreement between IP and the standard approach. 24 hours of baseline unanesthetized breathing was then recorded. After 24 hours, monkeys were re‐anesthetized, exposed to an aerosolized ascaris suum antigen and immediately returned to their cages. A subsequent 24 hours of recording provided data from each animal during and following a bronchoconstrictor response. Data indicate that ventilatory pattern is distinctly altered for a period of at least 60 minutes post challenge at which point breathing recovers to normal values. These data agree with our AUC measures in anesthetized animals after antigen exposure. The Φ for each breath was also calculated. During bronchoconstriction, a distinct different angle was measurable. Upon recovery, Φ returned to normal and remained stable, regardless breathing pattern. We conclude that this system is a useful tool to measure breathing in unencumbered, conscious animals for a long period and may be useful in evaluating bronchoconstrictor events.