How do chemically-induced comas work?
Deep sedation is used, with a variety of medications - usually
in an Intensive Care Unit (ICU). Pavulon is commonly used in order
to paralyze the muscles of respiration, and respiration is
accomplished for the patient via mechanical ventilation (e.g. the
patient is on a ventilator, with oxygen settings, respiratory rate
settings, inerposed sigh breaths, etc. ... with tubing running from
the ventilator into the patient who, by necessity, has an
endotracheal tube in place down to the trahea).
When the induced coma is no longer needed, ventilator settings
are gradually turned down, and then the patient is extubated (e.g.
the tube is removed from the patient).