Assessment of the Feasibility of Cardiorespiratory Monitoring in the Juvenile Minipig Using a Noninvasive Jacketed Telemetry System

Abstract

Cardiorespiratory assessments may need to be included in nonrodent juvenile animal studies performed to support the development of pediatric first/only pharmaceutical candidates if initial toxicology studies are not undertaken in adult animals or they are target functions. Cardiorespiratory assessments in adult dogs and minipigs are well established but this is not the case for juveniles, especially prior to weaning. Whilst electrocardiograms (ECG) are feasible using traditional methodology, respiratory monitoring has relied on manual clicker counts. This pilot test assessed the feasibility of customizing a noninvasive jacketed system (DECRO from ETISENSE, France) developed for cardiorespiratory monitoring of small mammals for the juvenile minipig.

Two 20-day old Göttingen Minipig piglets were equipped with the modified stretch jacket with integrated plethysmography sensors and a Bluetooth emitter. External small ECG electrodes were placed under the jacket. The emitter was connected to an acquisition server which executed DECRO-LASA software to process and display the data recorded for one hour in one unrestrained piglet. The jackets were left on the piglets so their status could be assessed over a period of approximately 24 hours. Cardiorespiratory parameters were successfully recorded and initial ECG (PR, QRS and QT intervals), heart rate and respiratory rate values in beats or breaths per minute (bpm) obtained using the DECRO system were compared with those from 32-day old control piglets from a previous juvenile toxicology study using traditional (ECG) or manual (respiratory rate) methodology.

Both respiratory rate (87 bpm) and heart rate (170 bpm) were comparable with the reference data (ranges of 28 to 91 bpm and 100 to 180 bpm, respectively). Duration of PR, QRS and QT intervals was in the same order of magnitude as determined in the adult minipig by invasive telemetry. The physiological QT/RR relationship was also present in the 20-day old piglet. One of the two fitted jackets was still in place after the 24-hour period and the findings provided valuable information to further adapt the jacket to allow monitoring over such periods. These results were sufficiently encouraging to continue development of the DECRO system for cardiorespiratory monitoring in nonrodent juvenile animal models, starting with the minipig.