A retrospective study of infant chest CT scans using mathematical modelling and a number of assumptions suggests that neonatal CPR according to AAP/AHA guidelines of compressing to one third anteroposterior chest wall diameter should provide a superior ejection fraction to 1/4 depth and should generate less risk for over-compression than 1/2 AP compression depth.
Evaluation of the Neonatal Resuscitation Program’s recommended chest compression depth using computerized tomography imaging
Resuscitation. 2010 May;81(5):544-8
Compare their conclusions with those of the authors of this case series of arterial-line monitored cardiac arrests in infants with a median age of one month