Evaluation of respiratory function in freely moving Beagle dogs using implanted impedance technology

Area of Science:

• Pharmacology
• Physiology
• Biomedical Engineering

Background:

• Safety pharmacology guidelines (ICH S7A) require preclinical evaluation of drug effects on respiratory function.
• Current methods in rodents have limitations like restraint stress and sensitivity issues.
• There is a need for accurate methods to assess respiratory function in conscious, freely moving large animals.

Purpose of the Study:

• To evaluate a novel surgically implanted telemetry device with an impedance sensor for chronic respiratory parameter measurement.
• To assess the feasibility and accuracy of this device in conscious Beagle dogs.
• To compare impedance-derived respiratory data with pneumotachograph recordings.

Main Methods:

• A telemetry device with an added impedance sensor was surgically implanted in Beagle dogs.
• Respiratory parameters were measured chronically using the telemetry device.
• Data concordance was assessed against pneumotachograph recordings after intravenous doxapram administration.

Main Results:

• A high correlation (R(2) = 0.95) was observed between impedance-derived tidal volume and respiratory frequency and pneumotachograph measurements under restrained conditions.
• Similar volume changes were recorded during ambulatory collection post-doxapram administration.
• Individual and population-based calibrations adequately approximated mean respiratory variables.

Conclusions:

• The telemetry device enables accurate, continuous measurement of respiratory endpoints in both restrained and ambulatory settings.
• Concurrent assessment of multiple physiological parameters and population-based calibrations can optimize resources and shorten drug development timelines.