Cryonics: Difference between revisions

Individuals enter cryonic suspension without any clothing. This is because clothing tends to bond to the skin at extremely low temperatures.<ref name="encyc1"/> Individuals who disregard this and enter cryo-sleep with clothing or bandages will often awake to find their skin blistered and raw.<ref>'''Halo: The Flood''', ''page 20''</ref> However, dedicated form-fitting full-body suits specifically designed for use in cryo can be worn without the ill effects of normal clothing, though the use of such suits is not very widespread within the UNSC military.<ref>'''Halo 4: Forward Unto Dawn'''</ref> [[Spartan]]s are also able to enter cryo with their [[Mjolnir armor]] on.<ref name="halolevel">'''Halo 3''', campaign level ''[[Halo (Halo 3 level)]]''</ref><ref>'''Halo 4''', campaign level ''[[Dawn]]''</ref>

The "put-down" cycle takes [[seven]] minutes.<ref name="encyc1"/> During the first four minutes anesthetic gas causes the subject to become drowsy. Then another gas reacts to form a [[bronchial surfactant]] when inhaled, coating the passages of the lungs to help ensure a smooth wake cycle.

[[Cytoprethaline]], a drug used by the UNSC during cryo-sleep, prevents damage to the occupants' cell membranes caused by ice crystal formation. It is recommended that a doctor administer the drug, but most of the time the shot is administered by a medic or by a pre-measured self-injector.<ref name="encyc1"/> Some humans, such as [[Thomas Lasky]], exhibit a rare allergic reaction to cytoprethaline. Due to the frequent use of cryosleep in the UNSC during interstellar voyages, severe instances of such condition are grounds for a medical discharge from UNSC service.<ref>[https://www.halowaypoint.com/en-us/universe/tech/cytoprethaline '''Halo Waypoint''': ''Cytoprethaline'']</ref> Spartan-IIs generally entered cryosleep without receiving cytoprethaline, but due to their augmentations, the Spartans likely did not need to receive such medication.<ref name="halolevel"/>

Once the subject is prepped, the chamber automatically proceeds to the freezing stage. The unit begins to rapidly cool the body and administers an electric current that precisely counters the normal wave across the heart muscle, stopping its rhythm. The unit reaches the optimal storage temperature in three minutes.<ref name="encyc1"/>

Once started, the wake cycle takes approximately fifteen minutes to complete. The subject is warmed in a controlled manner and an electric current is applied to stimulate the heart muscle. The lid of the chamber will open automatically when the cycle is completed, and the interior lighting increases to full brightness. Most sleepers do not awaken until this time.<ref name="encyc2"/>

When awakening, sleepers are required to sit erect in the chamber, take one breath, and cough. This first breath may be laborious to draw, but it is imperative to clear the lungs of surplus surfactant immediately.<ref name="encyc2"/> The surfactant is designed to be immediately swallowed in order to replace nutrients lost during the journey.<ref>'''[[Halo: The Fall of Reach]]'''</ref> Some UNSC personnel find the taste of the surfactant to be unpleasant.

If time is not of the essence, personnel may utilize the showers located adjacent to the cryo-bay deck. On military vessels, barracks and weapon lockers are often located near the cryo-deck so waking troops can be rapidly dressed and equipped for combat.<ref name="encyc2"/>

Accelerated waking, known as "flash thawing" is dangerous and has a high mortality rate, and is therefore only invoked in the most dire of emergencies. Emergency heating coils—coupled with a rapid infusion of stimulants, notably adrenaline—can bring a subject out of cryo-sleep in less than five minutes. In such cases, the subject's effectiveness is reduced for several hours and he or she is often disoriented.<ref name="encyc2"/>

[[SPARTAN-II program|SPARTAN-II's]] are augmented and specially trained to respond well to flash-thawing, and as a result suffer almost no ill effects.<ref name="encyc2"/>

If a subject fails to wake up, a medical resuscitation package is located at the end of each row of cryogenic chambers. All UNSC personnel are trained to use the device, which includes a heart stimulator and breathing mask. If the subject cannot be revived, the lid of the chamber should be closed, and the emergency freezing cycle activated. A physician should attend to the subject prior to subsequent reawakening.<ref name="encyc2"/> Another emergency action that cryonics can be used in is to prevent terminally-injured personnel from death, keeping them alive long enough to seek proper medical aid. The subject can be put under cryonics as long as they need until the necessary preparations have been made to resuscitate and perform surgery. [[Linda-058]], clinically dead because of injuries, was put into cryonics and eventually managed to survive when Catherine Halsey performed surgery on her by flash cloning kidneys and liver.<ref>''[[Halo: First Strike]]''</ref>

*Theoretically, no harm would come to subjects in suspension for hundreds of years or more, presuming no interruption occurred in the power supply to the chamber. However, there have been no instances where an individual was suspended for such a length of time.<ref name="encyc1"/>