Droplet Formation in Drugs During Extreme Temperature Conditions in the Emergency Medical Service, a Problem?

Area of Science:

• Emergency Medicine
• Pharmaceutical Science
• Aviation Medicine

Background:

• Helicopter emergency medical services (HEMS) frequently operate in cold environments, posing risks to stored medications.
• Drug emulsions like propofol and etomidate can degrade, forming lipid droplets, while amiodarone may crystallize, potentially causing adverse events.
• Understanding medication stability under cold exposure is critical for patient safety in prehospital care.

Purpose of the Study:

• To microscopically assess physical changes in common emergency drugs subjected to cold temperatures relevant to HEMS operations.
• To identify potential degradation pathways, such as lipid droplet formation or crystallization, under simulated HEMS conditions.

Main Methods:

• Drug samples were exposed to temperatures and durations mirroring real-world HEMS data from Switzerland.
• Exposure conditions included -2.3°C for 1 hour, 0.6°C to -3.6°C for 12 hours, and -22°C for 1 and 12 hours.
• Microscopic analysis was used to detect physical alterations in the drug formulations.

Main Results:

• No significant physical changes (lipid droplets or crystallization) were observed at -2.3°C.
• Lipid droplet formation was evident in propofol samples exposed to 0.6°C to -3.4°C for 12 hours and at -22°C for both 1 and 12 hours.

Conclusions:

• While common HEMS cold temperatures did not induce observable changes, prolonged exposure or deep freezing affected propofol stability.
• The formation of lipid droplets in propofol highlights the need for defined cold-exposure limits for prehospital medications.
• Further research is required to establish safe temperature thresholds for critical emergency drugs in austere environments.