Clinical death is the reversible transmission between life and biologic death. Clinical death is defined as the period of respiratory, circulatory and brain arrest during which initiation of resuscitation can lead to recovery. Clinical death begins with either the last agonal inhalation or the last cardiac contraction.
Signs indicating clinical death are
• The patient is without pulse or blood pressure and is completely unresponsive to the most painful stimulus.
• The pupils are widely dilated
• Some reflex reactions to external stimulation are preserved. For example, during intubations, respiration may be restored in response to stimulation of the receptors of the superior laryngeal nerve, the nucleus of which is located in the medulla oblongata near the respiratory center.
• Recovery can occur with resuscitation.
Biological death (sure sign of death), which sets in after clinical death, is an irreversible state of cellular destruction. It manifests with irreversible cessation of circulatory and respiratory functions, or irreversible cessation of all functions of the entire brain, including brain stem.However, one should notice that there are internationally accepted criteria to diagnose biological death.