Combined cardiopulmonary assessments with implantable telemetry device in conscious freely moving cynomolgus monkeys

Female cynomolgus monkeys were surgically implanted with telemetry transmitters recording ECG (DII), arterial pressure, physical activity, body temperature, and tidal volume. Respiratory rate (RR) and tidal volume (TV) were monitored simultaneously with the telemetry transmitter using impedance. Impedance-based monitoring of RR and TV by telemetry correlated with controlled TV and with pneumotachometer (> 98%) in restrained animals. Control drugs with cardiovascular and respiratory effects, including saline, medetomidine (0.01, 0.02 and 0.04 mg/kg) and cocaine (0.5, 1.0 and 1.5 mg/kg) were administered intravenously. An averaging epoch of 5 min was used for analysis of respiratory data. Medetomidine induced significant respiratory depression with decrease in RR and TV in freely moving animals while cocaine increased TV, RR and minute ventilation (MV) with concomitant increase in heart rate when compared with time matched values from saline-treated animals. The onset, duration and magnitude of cardiovascular and respiratory changes were correlated. This highlights the dependency of the cardiovascular and respiratory systems. The use of cardiopulmonary monitoring can allow continuous monitoring including during night time when variability of respiratory parameters is lower. Monitoring of cardiovascular and respiratory parameters in the same animals could also help to decrease the number of animals used in research.