Temperature <35.5°C (95.9°F).
Degree of hypothermia is proportional to mortality
Bradycardia
Hypotension
Pericardial effusion
Hypoventilation, hypercapnia
There is often diaphragmatic dysfunction that causes worsening hypoventilation.  The dysfunction is reversed after thyroid hormone administration
Early respiratory support with intubation may be necessary to prevent respiratory collapse
Hypoxia
Pleural Effusion
Upper airway obstruction from glottic edema, vocal cord edema, and macroglossia can complicate intubation.
There is often diaphragmatic dysfunction that causes worsening hypoventilation.  The dysfunction is reversed after thyroid hormone administration
Early respiratory support with intubation may be necessary to prevent respiratory collapse
Altered mental status/Coma due to CO2 narcosis<unk>  is very rare
Pseudomyotonic "hung up" deep tendon reflexes
Particularly Achilles reflex
Relaxation phase of DTR twice as long as contraction phase
Neuropsychiatric symptoms 
Depression
Psychosis
Particularly Achilles reflex
Relaxation phase of DTR twice as long as contraction phase
Depression
Psychosis
Myxedema coma
Adrenal crisis
Spinal shock
CHF
Neurogenic shock
CVA
Heat stroke
Depression