The results of designing a new prototype device and algorithm in closed method intraperitoneal hyperthermia model in rats.

Background: There is currently no standard medical device and method available for hyperthermic intraperitoneal therapy studies in rats. In this study, we present our designed device and algorithm that operates based on our own protocol for hyperthermic intraperitoneal treatment in rats. The aim was to demonstrate the effectiveness of the designed device, algorithm, and hyperthermia protocol by showing that the device can achieve the desired temperature inside the rat's abdomen, does not cause rat loss due to complications, operates autonomously, and provides warnings to the operator in case of emergencies.

Methods: A closed method for intraperitoneal hyperthermia protocol was established for 6 female 8-week-old (280-310 g) albino Wistar rats. Fluid inlet and outlet tubes and a temperature probe were inserted through a 1 cm vertical incision between the xiphoid and bladder in the rat's abdomen, and the skin was sutured in a circular manner. A protocol for intraperitoneal hyperthermic treat-ment was established using a saline solution at a flow rate of 100 mL/min for 60 min, maintaining a temperature of 41°C±0.5 inside the rat's abdomen.

Results: During the study, a temperature of 41°C±0.5 was successfully achieved in the abdomen of all rats at a flow rate of 100 mL/min±5 for 60 min. Due to three rats reaching a rectal temperature above 38.5°C during the hyperthermia protocol, external cooling was applied to the rat's tail base using ice. There were no losses until the postoperative 72nd h, and the study was successfully completed.

Conclusion: Our designed device and algorithm, which prioritize animal welfare, operate rapidly, safely, and with high accuracy sensitivity, have been successful in hyperthermic intraperitoneal treatment studies in rats. We believe that they can be used as a stan-dard method and approach in hyperthermic intraperitoneal studies in rats.