<unk>  is caused by apnea (cessation of breathing) or<unk>  dysfunction severe enough it will not sustain the body (such as agonal breathing). Prolonged apnea refers to a patient who has stopped breathing for a long period of time. If the heart muscle contraction is intact, the condition is known as<unk> . An abrupt stop of pulmonary gas exchange lasting for more than five minutes may damage vital organs especially the brain, possibly permanently. Lack of oxygen to the brain causes loss of consciousness. Brain injury is likely if<unk>  goes untreated for more than three minutes, and death is almost certain if more than five minutes. Damage may be reversible if treated early enough.<unk>  is a life-threatening medical emergency that requires immediate medical attention and management. To save a patient suffering from<unk> , the goal is to restore adequate ventilation and prevent further damage. Management interventions include supplying oxygen, opening the airway, and means of artificial ventilation. In some instances, an impending<unk>  could be predetermined by signs the patient is showing, such as the increased work of breathing.<unk>  will ensue once the patient depletes their oxygen reserves and loses the effort to breathe.<unk>  should be distinguished from<unk>  failure. The former refers to the complete cessation of breathing, while<unk>  failure is the inability to provide adequate ventilation for the body's requirements. Without intervention, both may lead to decreased oxygen in the blood (hypoxemia), elevated carbon dioxide level in the blood (hypercapnia), inadequate oxygen perfusion to tissue (hypoxia), and may be fatal.<unk>  is also different from cardiac arrest, the failure of heart muscle contraction. If untreated, one may lead to the other.
Respiratory arrest
Cardiac arrest
Sleep paralysis
Syncope 
Expiratory apnea
Spinal shock
Permissive hypotension
Inert gas asphyxiation