Improving the Accuracy of Constant Temperature Monitoring of Open-Air Stereo Stages

Abstract

Background: Temperature regulation and monitoring is critical in IVF laboratories. Constant temperature monitoring of open-air stereo stages has proven to be a difficult feat, as probes are exposed to ambient air, making readings irreflective of actual temperature within media. Aim: To determine the substrate that most accurately reflects the temperature of culture media on an open stereo-stage. Method: Media under oil was temperature logged on a stereo stage simultaneously with six different dish setups, each fitted with a temperature probe: empty dish, large steel spheres (5mm), small steel spheres (2mm), ultrasound gel, silicone mold and ceramic balls. The dish set up that most consistently reflected media temperature was further assessed to determine how closely it mimicked the warming rate of media, measured in 1-minute intervals over a 20-minute period. Results: The media logged an average temperature of 36.99°C with a tight range of 36.9°C−37.1°C. The commonly used empty dish recorded an average temperature of 35.44°C with a range of 35.06°C−35.81°C. The tested substrates, listed in ascending order of efficacy, measured as follows: ceramic balls −33.65°C (33.01°C−33.97°C), large steel spheres −33.16°C (35.03°C−35.31°C), silicone mold −35.67°C (35.40°C−36.01°C) and ultrasound gel −36.24°C (36.5°C−36.41°C). The small steel spheres replicated the media temperature most accurately, with an average temperature of 36.48°C and the least variation (36.38−36.60°C). When warmed from room temperature to 37.0°C, the small steel spheres were closely comparable to the warming rate of the media, with rates of 0.94°C per minute and 1.1°C per minute, respectively. Both reached range within 12-minutes. Conclusion: Small steel spheres can substitute for culture media during temperature monitoring, allowing accurate constant monitoring of open-air stage temperature, and are closely comparable to the warming rate of media.