The new challenging pediatric patient.

The 'new' challenging pediatric patients are those who could be called 'the survivors' and neonates undergoing birth under materno-fetal circulation. Their anesthetic management is complex because their initial pathology was previously lethal: the physiologic, pharmacologic, and or technical aspect of their management is presently unknown or hypothetical. Some examples are described. Communication with the pediatrician in charge of the child is the key to safe and effective anesthetic care of these cases.