Stability of Blood Clotting Products Stored in Emergency Ambulances Under Real-World Conditions (STABLE-EMS)

Emergency medical service (EMS) medications and blood products are routinely exposed to varying environmental conditions during storage and transport. Seasonal temperature fluctuations, prolonged vehicle operation, and environmental influences may result in deviations from manufacturer-recommended storage conditions. While several studies have demonstrated the stability of commonly used emergency medications under real-world prehospital conditions, limited evidence is available regarding the stability of blood coagulation products stored in EMS vehicles.

Human fibrinogen concentrates and lyophilized human plasma (Octaplas LG AB) are increasingly available in prehospital emergency care for the early management of severe hemorrhage and trauma. Both products are subject to specific storage requirements defined by the manufacturer. Although these products are intended to be stored under controlled conditions, maintaining recommended storage environments continuously in operational EMS vehicles may be challenging, particularly during periods of elevated ambient temperatures. Data regarding the impact of such environmental exposure on product stability in the prehospital setting remain scarce.

The objective of this prospective observational longitudinal study is to evaluate the stability of fibrinogen concentrates and Octaplas LG AB when stored under routine operating conditions in a ground-based EMS ambulance in Graz, Austria. The study will be conducted during the summer months from July through September 2026, representing the period with the highest expected thermal stress on medical products stored in emergency vehicles.

At study initiation, reference samples of both products will be retained under manufacturer-recommended storage conditions. Additional study samples will be placed in the ambulance medication storage system and exposed to routine operational conditions throughout the observation period. Laboratory analyses will be performed at predefined monthly intervals to assess potential changes in product stability over time. All analyses will be conducted at the Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, using validated laboratory methods appropriate for each product. Product-specific stability parameters will be compared with baseline and reference samples stored according to manufacturer recommendations.

Environmental conditions will be continuously monitored throughout the study period. Temperature sensors will be installed both within the medication storage containers and inside the ambulance vehicle. Measurements will be recorded automatically at 10-minute intervals over the entire observation period. These data will be used to characterize environmental exposure profiles and to quantify the frequency, magnitude, and duration of deviations from recommended storage conditions.

The primary objective is to determine whether storage under real-world prehospital operating conditions results in measurable changes in the stability of fibrinogen concentrates and Octaplas LG AB over a three-month observation period. Secondary objectives are to characterize temperature conditions within EMS medication storage systems, assess compliance with manufacturer-recommended storage conditions, quantify environmental excursions outside recommended storage ranges, evaluate potential associations between environmental exposure and laboratory measures of product stability, and describe seasonal storage conditions encountered in a ground-based EMS system.

No patients will be enrolled, and no clinical interventions will be performed as part of this study. The investigation is limited to pharmaceutical product samples and environmental monitoring within an operational EMS vehicle. Consequently, no patient-related outcomes, safety endpoints, adverse events, or clinical efficacy outcomes will be assessed.

Descriptive statistics will be used to summarize environmental and laboratory data. Continuous variables will be reported as means with standard deviations or medians with interquartile ranges, as appropriate. Longitudinal changes in laboratory stability parameters will be assessed across repeated measurements obtained during the observation period. Associations between environmental variables, including temperature and laboratory indicators of product stability will be explored using correlation analyses and regression-based approaches where appropriate. Missing measurements, if encountered, will not be imputed and will be reported transparently.

The results of this study are expected to provide evidence regarding the suitability of current EMS storage practices for blood coagulation products under routine operating conditions. The findings may contribute to future recommendations for the storage, transport, and quality assurance of coagulation products used in prehospital emergency medicine.