Bronchial surfactant

Bronchial surfactant is an enzyme used by humans for use in cryo chambers. The cryo-inhalant is specifically designed to coat and protect the lungs when entering cryo-sleep, then be regurgitated and swallowed upon reawakening. The clear liquid replaces some vital bodily fluids, such as nutrients lost during deep sleep. A person using bronchial surfactant is theoretically able to sleep for extremely long periods of time, thus making it possible that it includes some sort of sedative. However, the exact specifications are not known. People have been observed in cryo-sleep for up to three weeks without using the fluid.

Most people didn't have a problem using the drug, but Jacob Keyes had a profound disgust for it, believing that no matter how the formula is changed, it always tasted like "lime-flavored mucus."

List of appearances

• Halo: The Fall of Reach (First appearance)
• Halo: Evolutions - Essential Tales of the Halo Universe
  • Dirt
• Halo 4: Forward Unto Dawn