Agonal respiration, gasping respiration or agonal breathing is an abnormal pattern of breathing and brainstem reflex characterized by gasping, labored breathing, accompanied by strange vocalizations and myoclonus. Possible causes include cerebral ischemia, extreme hypoxia or even anoxia. Agonal breathing is an extremely serious medical sign requiring immediate medical attention, as the condition generally progresses to complete apnea and heralds death. The duration of agonal respiration can be as brief as two breaths or last up to several hours. The term is sometimes (inaccurately) used to refer to labored, gasping breathing patterns accompanying organ failure (e.g. liver failure and  renal failure), SIRS, septic shock, and metabolic acidosis (see Kussmaul breathing, or in general any labored breathing, including Biot's respirations and ataxic respirations). Correct usage would restrict the term to the last breaths before death.