Stability of Drugs Used in Helicopter Air Medical Emergency Services: An Exploratory Study

Objective Transportation by air exposes drugs used in emergency medical services to vibrations. The aim of the study was to determine whether or not vibrations caused by a helicopter induce the degradation of 5 drugs used in this setting. Methods A longitudinal study in an operating medical helicopter along with a worst case was conducted. The studied drugs were 3 drugs labeled for refrigeration (cisatracurium, lorazepam, and succinylcholine) and 2 albumin solutions (human albumin 4% and 20%). These drugs were stored for 4 months according to the following conditions: inside a helicopter, worst case with exposure to extreme vibrations, at room temperature, and according to manufacturers’ recommendations. Samples were analyzed with validated high-performance liquid chromatography assay methods. A drug was considered stable if the remaining drug content was above 90% of the label claim. Except for the albumin solutions, visual inspection was used to determine instability by the formation of aggregates. Results Only the samples stored at room temperature became unstable after 4 months. No difference in extreme foaming was observed in the albumin solutions. Conclusions These data suggest that the effect of degradation of drugs caused by vibrations is negligible. Temperature was observed as the main cause of drug degradation. The impact of temperature exposure on drug deterioration during ground transportation for the delivery of emergency medical services (EMS) has already been studied in real-world settings.1, 2 and 3 However, no studies were performed thus far to determine the impact of vibrations on drug stability in ground or in air medical transportation. Although the underlying mechanism remains unclear, vibrations may affect drug stability as a result of the initial rise in temperature caused by energy expenditure or as a result of interactions with surfaces (eg, vial-water interfaces).4, 5 and 6 Previous studies showed that cisatracurium, lorazepam, and succinylcholine, when exposed to prehospital conditions, became unstable in a few weeks or months, suggesting that these might also be susceptible to vibrations.2 and 3 Cisatracurium and succinylcholine are both muscle relaxants and are used to assist endotracheal intubation. Lorazepam is used to treat status epilepticus. Furthermore, it is described that most proteins, including albumin solutions, form precipitates by adsorption to solid surfaces when sufficient agitation or shear forces are introduced.5 Albumin 4% and 20%, both albumin solutions, are used as fluid resuscitation in patients with sepsis. Vibration is inherent to all transport vehicles, but it has been shown that air transfers are characterized by higher frequencies and higher lateral (side to side) and anterior-posterior (chest to back) accelerations; however, these are considered as more stable vibrations compared with ground transportation.7 The aim of this study is to determine whether vibrations caused by helicopter transport results in the degradation of these 5 essential drugs used in helicopter emergency medical services (HEMS).

Publication year:2016

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