The Effects of Tropical Climate on the Stability of Emergency Drugs Used in Ambulances Under Real EMS Situations

Abstract

Objectives: Adrenaline (epinephrine), amiodarone, and atropine are included in the 2020 Advanced Cardiac Life Support guideline and are commonly used during cardiopulmonary resuscitation in both prehospital and in-hospital situations. The emergency drug boxes are often exposed to high ambient temperatures and very humid climates in the tropical regions. These accelerated conditions can significantly impact the drug stability. It is crucial to ensure that these medications maintain their potency to provide optimal patient care. Methods: Three medications, including adrenaline, amiodarone, and atropine, were packed into the emergency medical service (EMS) drug box in the resuscitation backpack. It was stored in a controlled storage environment during the non-operation periods. The resuscitation backpack was taken to the EMS operations, which were exposed to ambient temperature during the missions. All medications were divided into five batches, each of which was sent for analysis of the active ingredient every 3 months over a 12-month period using the High-Performance Liquid Chromatography method. The predicted concentrations of these three medications were analyzed using regression analysis. Results: During a 12-month period, there were a total of 450 prehospital missions. The average ambient temperature was 30.1 °C (SD 2.09 °C), and the average relative humidity was 72.18% (SD 14.96%). The temperature of the EMS drug box was 25.2 °C (SD 1.65 °C), while the relative humidity was 65.22% (SD 4.35%). The mean kinetic temperature, assessed at 3-month intervals, ranged from 25.0 °C to 25.8 °C. All medications contained active ingredient levels above the regulated standards, while maintaining the drug degradation below 10% over a 12-month period. Conclusions: In a hot and highly humid EMS climate with careful adherence to EMS medication storage protocol, adrenaline, amiodarone, and atropine maintained sufficient stability over a 12-month period when stored in a controlled environment during non-operating hours. Only atropine was predicted to degrade faster than the manufacturer’s recommended expiration period.