Protective responses of the newborn to hypoxia.

In human infants, spontaneous recovery from sleep related apnea or positional asphyxia can occur early with or without behavioral and/or cortical arousal or later as a result of autoresuscitation from "asphyxial coma" by hypoxic gasping. Because it occurs when early defense mechanisms are absent or fail to resolve apnea or positional asphyxia, autoresuscitation serves as a backup mechanism and is considered to be the last operative mechanism used by mammals to ensure survival during exposure to severe hypoxia. In this short review, factors will be considered that influence the onset, duration and number of potential autoresuscitation producing gasps as well as the integrated physiology of successful autoresuscitation and pathophysiology of failed autoresuscitation from hypoxic-induced apnea.