The dynamic nature of the prehospital environment poses a challenge for maintaining optimal storage conditions for medicines and other products. Failure to ensure adequate temperature control can impact drug efficacy, potentially compromising effective prehospital care. This study aims to monitor temperature variations in vehicles operated by a helicopter Emergency Medical Service (EMS) in the east of England to evaluate temperature variation and the potential exposure of therapeutic products to extreme temperatures.

This was a prospective observational study over a 12-month period (September 2022 through August 2023). ALTA Industrial Wireless temperature sensors were deployed across five Volvo XC90 rapid response vehicles (RRVs) and an AgustaWestland 169 (AW169) helicopter operated by Essex & Herts Air Ambulance (EHAAT). One RRV (RRV02) remained permanently outside for the period of observation. Sensors recorded at 30-minute intervals, triggering alerts if temperatures exceeded 25°C or dropped below 2°C. Ambient data were obtained from the Writtle Weather Station, via the Met Office Integrated Data Archive System (MIDAS). The study did not involve any patients and ethical board review was not required.

A total of 102,524 readings were recorded; temperatures ranged from −9°C to 46.8°C. The RRV02 recorded the lowest monthly mean (7.9°C) while the AW169 recorded the highest (24.9°C). Overall, daily maximum temperatures ranged from 17.7°C to 46.8°C, with the AW169 reaching 46.8°C in May. Daily minimum values ranged from −9°C to 19.6°C, with the RRV02 recording −9°C in December.

Temperatures inside the vehicles and aircraft frequently exceed recommended limits for environmental temperatures. Indoor RRV storage provides some protection from extreme temperatures, particularly mitigating against low temperatures. The AW169 aircraft demonstrated the poorest overall temperature control. These results can be used to guide effective storage protocols and climate control strategies to ensure the integrity of therapeutic products.