Successful implantation of an abdominal aortic blood pressure transducer and radio-telemetry transmitter in guinea pigs: anaesthesia, analgesic management and surgical methods, and their influence on hemodynamic parameters and body temperature

Abstract

Introduction Guinea pigs (GPs) are a valuable cardiovascular pharmacology model. Implantation of a radio-telemetry system into GPs is, however, challenging and has been associated with a high failure rate in the past. We provide information on a novel procedure for implanting telemetry devices into GPs and we have measured the hemodynamics (arterial blood pressure, BP and heart rate, HR) and core body temperature (BT) in the 24 h after surgery. Methods Male Hartley GPs (Crl:HA, 350-400 g, 6.5 weeks, n = 16) were implanted with a radio transmitter abdominally and were then monitored continuously (HR, BP and BT) for 24 h after surgery. Results 13 of 16 GPs (81%) survived the surgery. Surgery duration was 94 min (min) (range: 76–112 min) and anaesthesia duration was 131 min (range: 107–158 min). GPs lost body weight until 2 days after surgery and then regained weight. Mean arterial BP increased from 33.7 mm Hg directly after surgery to 59.1 mm Hg after 24 h. HR increased from 206 bpm directly after surgery to 286 bpm at 8 h and fell to 251 bpm at 24 h after implantation. BT was 36 °C directly after surgery, fell to 35.4 °C until regaining of the righting reflex and then stabilized at 38.5 °C after 24 h. Discussion A high survival rate in telemetered GPs is possible. We achieved this through a procedure with minimal stress through habituation and planning, continuous warming during anaesthesia, an optimal anaesthetic and analgesic management, efficient surgical techniques and vitamin C supplementation